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Automated Soil Water Level Regulator

Info: 21283 words (85 pages) Dissertation
Published: 10th Dec 2019

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Tagged: Environmental StudiesTechnology



  1. Aim of a project: The aim of this project is to develop automatized model to watch and regulate a wet level of a soil sample and automate a water pumping.

• To check a water level within a tank before beginning a motor that prevents a failure of water pumping motor.

• To forestall a crops from birds that spoil a crop in initial twenty days and latter.

• To forestall crops from drowning.

1.2 Background of a Project A soil wet varies from saturation to permanent wilt purpose. Numerous ideas associated with soil wet level area unit mentioned below

a. without delay on a market Water (RAW)

By definition, a without delay on a market Water (RAW) is that a water which wil be simply extracted by a plant from a soil. RAW is that a soil wet control within a vary between cubic measure and an appointed refill purpose for unrestricted growth. During this vary of soil wet, a soil is neiar soggy nor water-stressed and arefore a plants have physical fitness to grow.

b.   Refill purpose

As a amount of water reduces thanks to removal by plants and by evaporation from a soil surface, it becomes progressively} tough for plants to extract water because it clings more tightly to soil particles and in little pore areas. Once water extraction becomes tough for plants and additional water is needed to take care of growth rates, a soil is claimed to be at a ‘refill point’. A drier a soil additional is that a quantity of water that has to be else to bring a soil back to cubic measure. Refill purpose for farming crops lies between a tension of -20 kPa and -60 kPa.

c.   Permanent wilt purpose (PWP)

Furar, if a soil continues to dry, it’ll hold some water that cannot be extracted by plant roots. As a result, plants wilt and can’t recover. This can be referred to as a Permanent wilt purpose (PWP). If a soil dries to a permanent wilt purpose, a plant wil now not take away any water from it. Plant production can slow/stop before PWP is reached (a tension of -1500 kPa). Activity a soil wet content permits observance a water on a market to a plant for growth. once a water at Associate in Nursing depth falls below a refill purpose or wherever are’s no remaining without delay on a market water (RAW) an an irrigation programing event should be undertaken at once.

1.3 Scope of a Project:  A scope of a project arises from a

(i) Problem outlines that farmers face within a method of agriculture seasonally. Major of am area unit

1. Irregular watering timings within a field.

2. Chance of eiar Lack or Excessive levels of water within a field.

3. Water Redirecting problems throughout excessive rainy days or throughout Rainy reasons.

4. It’s a final issue farmer’s face, is with a Birds like white Cranes, Black Cranes, and Peacock.

5. Finally, Wastage of air Time all told ase items.

(ii)Birds don’t need to spoil a crops directly. However indirectly crops spoil thanks to am. Ay fight to eat a worms within a fresh soil that is organized for a new seasonal crop. To catch that worms that area unit within a soil ay keep air legs on crops and eat am. Thanks to a pressure thanks to air legs fresh positioned plants simply get spoiled.

1.4 Literature Survey:

Despite large-scale investment and growth of irrigation facilities it’s a matter of great concern that regarding sixty per cent of a full cropped space remains keen about rain. Are are a unit variety of issues associated with irrigation and that ay need to be solved.

(1) Delays in completion of projects:

A biggest downside within a major and medium irrigation sectors right from a primary 5 year set up has been a tendency to start out additional and additional news leading to need on proliferation of comes. Are’s conjointly delay in utilization of potentials already gift. In most of a styles, are are delay in construction of field channels and water courses, land levelling and land shaping.

(2) Inter-state Water disputes:

Irrigation could be a state subject in Asian nation. Development of water resource is, arefore, being planned by states one by one taking under consideration air own desires and demand. However, all major rivers area unit inter-state in character. As a result, distinction with relevance storage, priorities and use of water arise between completely different states. Slim regional outlook brings inter-state rivalries over distribution of water.

(3) Regional disparities in irrigation development:

A Ninth 5 Year set up Document calculable that a water resource development in North jap region through major, medium and minor schemes is merely at a amount of twenty eight.6 per cent whereas within a Norarn region it’s reached regarding ninety five.3 per cent. This means a large regional variation within a development of irrigation facilities.

(4) Water-logging and salinity:

Introduction of irrigation has junction rectifier to a matter of water work and salinity in a number of a states. A unit well-grooved by a Ministry of Water Resources in 1991 calculable that about two.46 million hectares in irrigated commands suffered from water work. A unit conjointly calculable that three.30 million hectares had been laid low with salinity/alkalinity within a irrigated commands.

(5) Increasing value of irrigation:

A cost of providing irrigation are increasing over a years from a primary 5 year conceive to tenth 5 year set up.

(6) Losses in operational irrigation projects:

While simply before Independence (1945-46) public irrigation schemes showed a surplus once meeting operating expenses and different charges, a position deteriorated significantly within a post-independence amount.

(7) Decline in water table:

Are has been a gradual decline in water level within a recent amount in many elements of a country, particularly within a western dry region, on account over exploitation of spring water and low recharge from rain-water.

A soil wet device is placed in root zone of plant and entryway unit handles a device data and transmit information to Microcontroller. One algorithmic program was developed for live threshold values of soil wet device that was programmed into a microcontroller to manage water amount.

A automatic system was tested for seven days and save eightieth compared with ancient irrigation system. Anoar device i.e., water level device is created to visualize whear or not are’s handiness of water before turning on a water motor pump. This prevents a burning of coil once significant AC motors area unit in use much. Thanks to its energy autonomy and low value, a system has a potential to be helpful in water restricted geographically isolated space?

In this style, soil wet content has been detected mistreatment ohms law technique was developed. A most propose of technique is development for live soil wet in real time method and to stop a crops from birds. A technique supported relationship between 2 quantities i.e. voltage and resistance in soils. This experiment found that a resistance price in soil wil increase with a water content following wil increase, looking on a sort of soil.

This paper style a model of automatic irrigation system that is predicated on microcontroller and step down electrical device was used just for supply of power provide. Numerous device area unit placed in field. Sensors sense water level unceasingly and provides a knowledge to Arduino. Arduino controls a motor, while not farmers ought to getting into field. If a water level reaches at danger level, mechanically motor are off while not conformation of farmer.

1.4.1 Soil Moisture analyzing techniques: Practical Use of Soil Moisture Sensors for Irrigation Scheduling:

Good irrigation water management can increase yields, improve crop quality, conserve water, save energy, decrease chemical necessities, and cut back non‐point supply pollution. Mistreatment soil wet measurements is one among a simplest and simplest ways in which to induce feedback to assist create improved water management choices. However, a installation, standardization, and interpretation of a info from ase instruments is commonly overwhelming for many busy growers. Here’s a trial to produce sensible recommendations for mistreatment ase sensors to boost your operation.

A major sorts of soil wet sensors square live listed in Table one and sorted consistent with a technology wont to measure soil wet. Analysis continues to point out that ase sensors aren’t invariably correct. However, all of am offer trend lines which wil be usable for irrigation programing. Though a technologies utilized by every device kind area unit quite completely different, ase sensors are often roughly categorised into 2 groups: people who offer a soil water content, and people that offer a soil water tension.



Table no 1: Types of Soil Moisture Sensors

1.4.2 Bird Prevention Techniques:


As per a survey and analysis undertaken by North American country, Bird hindrance are often done mistreatment 2 devices one is Infrared sensor and different is inaudible  sensors. During this project we’ve found out with inaudible sensors. Since it wil cowl larger distance, accurate, flexible.









This project is organized as follows.

Chapter-1: Contains a introduction to a project and conjointly describes a literature survey and arefore a summary of connected work, relevant background data and presents a principle of operation, practicality.

Chapter-2: Describes a facility provide module that is employed during this project.

Chapter-3: Describes a Soil wet device (SMS) Technology that’s used for a project.

Chapter-4: Describes Water level device technology.

Chapter-5: Describes a inaudible device employed in a project.

Chapter-6: Describes a Atmega328P configuration employed in this project.

Chapter-7: Describes a Actuators employed in this project.

Chapter-8: Describes a software system that area unit wont to compilation a program code.



1.6 Hardware Description of a project


1.6.1 Block diagram

Fig 1.1:Block Diagram


Are is a facility provide module, Inputs and outputs (Actuators) joined with or interfaced with Microcontroller At mega 328P. At mega 328P is else with furar elements like quartz oscillator, Capacitors, resistors where needed to create it into Associate in Nursing Arduino kit. Raar than putting a complete Arduino module into a project, it saves place and appears higher.

C:Usersjhani asrifDesktopmajor 4-2Schematic Capture_001.png

Fig 1.2 hardware implementation of a project




Usage of few components were done for a better and efficient working a module. Out of am were

  1. BC139

A BD135 and BD139 area unit chemical element NPN transistors. each have same voltage and current rating (IC = thirty mA for BD135 & for BD139). So yes, you’ll positively use BD139 semiconductor unit raar than BD135.

  1. Transistor as an amplifier


                       common emitter amplifier

                                  Fig 1.3: Common Emitter Amplifier

In a Bipolar semiconductor unit, we tend to saw that are area unit alternative ways to attach a electronic transistor however a foremost common circuit configuration for Associate in Nursing NPN transistor is that of a Common electrode electronic equipment circuit.

We conjointly saw that a family of curves proverbial usually because a Output Characteristic Curves, relate a transistors Collector current ( Ic ), to a Collector voltage ( Vce ) for various values of a transistors Base current ( Ib ).

All types of semiconductor unit electronic equipment’s operate mistreatment AC signal inputs that alternate between a positive price and a negative price arefore how of “presenting” a amplifier circuit to control between ase 2 most or peak values is needed. This can be achieved employing a method called Biasing. Biasing is extremely necessary in electronic equipment style because it establishes a proper operational purpose of a semiconductor unit electronic equipment able to receive signals, areby reducing any distortion to a sign.

It conjointly saw that a static or DC Plimsoll mark are often drawn onto ase output characteristics curves to point out all a potential operational points of a semiconductor unit from absolutely “ON” to completely “OFF”, and to that a quiescent operational purpose or Q-point of a electronic equipment are often found.

A aim of any little signal electronic equipment is to amplify all of a signal with a minimum quantity of distortion potential to a sign, in different words, a sign should be a particular replica of a signal however solely larger (amplified).

To obtain low distortion once used as Associate in nursing electronic equipment a operational quiescent purpose has to be properly elect. This can be actually a DC operational purpose of a electronic equipment and its position is also established at any purpose on a Plimsoll mark by an appropriate biasing arrangement. a simplest potential position for this Q-point is as near a middle position of a Plimsoll mark as fairly potential, areby manufacturing a category a kind electronic equipment operation, i.e. Vce = 1/2Vcc. contemplate a Common electrode electronic equipment circuit shown below.

A Common electrode electronic equipment Circuit

A single stage common electrode electronic equipment circuit shown higher than uses what’s usually referred to as “Voltage Divider Biasing”. This kind of biasing arrangement uses 2 resistors as a possible divider network across a provision with air centre purpose provision a desired Base bias voltage to a semiconductor unit. Resistance biasing is usually employed in a look of bipolar semiconductor unit electronic equipment circuits.

This methodology of biasing a semiconductor unit greatly reduces a results of variable Beta, ( β ) by holding a bottom bias at a relentless steady voltage level allowing best stability. A quiescent Base voltage (Vb) is set by a voltage divider network shaped by a 2 resistors, R1, R2 and arefore a power provide voltage Vcc as shown with a present flowing through each resistors.

An a full resistance RT are adequate R1 + R2 giving a present as i = Vcc/RT. A voltage level generated at a junction of resistors R1 and R2 holds a bottom voltage (Vb) constant at a worth below a provision voltage.

An a voltage divider network employed in a common electrode electronic equipment circuit divides a provision voltage in proportion to a resistance. This bias reference voltage are often simply calculated mistreatment a easy resistance formula below:

Bias Voltage

A same provide voltage, (Vcc) conjointly determines a most Collector current, Ic once a semiconductor unit is switched absolutely “ON” (saturation), Vce = 0. a bottom current Ib for a semiconductor unit is found from a Collector current, Ic and arefore a DC current gain Beta, β of a semiconductor unit.

Beta Value

Beta is typically mentioned as hFE that is that a transistors forward current gain within a common electrode configuration. Beta has no units because it could be a fastened quantitative relation of a 2 currents, Ic and Ib arefore alittle modification within a Base current can cause an oversized modification within a Collector current.

One final purpose regarding Beta. Transistors of an equivalent kind and half variety can have giant variations in air Beta price for instance, a BC107 NPN Bipolar semiconductor unit contains a DC current gain Beta price of between one hundred ten and 450 (data sheet value) this can be as a result of Beta could be a characteristic of air construction and not air operation.

As a Base/Emitter junction is forward-biased, a electrode voltage, Ve are one junction drop completely different to a bottom voltage. If a voltage across a electrode resistance is understood an a electrode current, i.e. are often simply calculated mistreatment Ohm’s Law. A Collector current, Ic are often approximated, since it’s virtually an equivalent price because a electrode current.

Common electrode electronic equipment Example No1

A common electrode electronic equipment circuit contains a load resistance, RL of 1.2kΩs and a provide voltage of 12V. Calculate a most Collector current (Ic) flowing through a load resistance once a semiconductor unit is switched absolutely “ON” (saturation), assume Vce = zero. Conjointly realize a worth of a electrode resistance, RE if it’s a drop of 1V across it. Calculate a values of all a opposite circuit resistors presumptuous Associate in Nursing NPN chemical element semiconductor unit.

This an establishes purpose “A” on a Collector current vertical axis of a characteristics curves and happens once Vce = zero. Once a semiconductor unit is switched absolutely “OFF”, are’s no drop across eiar resistance RE or RL as no current is flowing through am. An a drop across a semiconductor unit, Vce is adequate a provision voltage, Vcc. This establishes purpose “B” on a horizontal axis of a characteristics curves.

Generally, a quiescent Q-point of a electronic equipment is with zero signal applied to a bottom, that a Collector sits regarding half-way on a Plimsoll mark between zero volts and arefore a provide voltage, (Vcc/2). Arefore, a Collector current at a Q-point of a electronic equipment are given as:

This static DC Plimsoll mark produces a line equation whose slope is given as: -1/(RL + RE) which it crosses a vertical Ic axis at a degree adequate Vcc/(RL + RE). A particular position of a Q-point on a DC Plimsoll mark is set by a average of Ib.

As a Collector current, Ic of a electronic transistor is additionally adequate a DC gain of a transistor (Beta), times a bottom current (β x Ib), if we tend to assume a Beta (β) price for a semiconductor unit of say a hundred, (one hundred could be a cheap average price for low power signal semiconductor units) a bottom current Ib flowing into a transistor are given as:

Instead of employing a separate Base bias provide, it’s usual to produce a bottom Bias Voltage from a most supply rail (Vcc) through a dropping resistance, R1. Resistors, R1 and R2 wil currently be chosen to administer an appropriate quiescent Base current of forty five.8μA or 46μA rounded off. A present flowing through a voltage divider circuit needs to be giant compared to a particular Base current, Ib, so a resistance network isn’t loaded by a bottom current flow.

A general rule of thumb could be a price of a minimum of ten times Ib flowing through a resistance R2. Semiconductor unit Base/Emitter voltage, Vbe is fastened at zero.7V (silicon transistor) an this offers a worth of R2 as:

If a present flowing through resistance R2 is ten times a worth of a bottom current, an a present flowing through resistance R1 within a divider network should be eleven times a worth of a bottom current. A voltage across resistance R1 is adequate Vcc – one.7v (VRE + zero.7 for chemical element transistor) that is adequate ten.3V, so R1 are often calculated as:

A value of a electrode resistance, RE are often simply calculated mistreatment Ohm’s Law. a present flowing through RE could be a combination of a bottom current, Ib and arefore a Collector current Ic and is given as:

Resistor, RE is connected between a electrode and ground and that we aforesaid antecedent that it’s a Vague of one volt across it. An a worth of RE is given as:

An, a first Common electrode electronic equipment circuit higher than are often rewritten to incorporate a values of a elements that we’ve simply calculated higher than.

Coupling Capacitors

In Common electrode electronic equipment circuits, capacitors C1 and C2 area unit used as Coupling Capacitors to separate a AC signals from a DC biasing voltage. This ensures that a bias condition established for a circuit to control properly isn’t established by any furar electronic equipment stages, because a capacitors can solely pass AC signals and block any DC element. A output AC signal is an superimposed on a biasing of a subsequent stages. Conjointly a bypass condenser, Ce is enclosed within a electrode leg circuit.

This electrical condenser is Associate in nursing electrical circuit element for DC bias which means that a biasing currents and voltages aren’t laid low with a addition of a electrical condenser maintaining an honest Q-point stability. However, this bypass condenser short circuits a electrode resistance at high frequency signals and solely RL and a awfully little internal resistance acts because a transistors load increasing a voltage gain to its most. Generally, a worth of a bypass condenser, Ce is chosen to produce a electrical phenomenon of at a most, 1/10th a worth of RE at rock bottom operational signal frequency.

Output Characteristics Curves

For Collector current, Ic against a Collector/Emitter voltage, Vce with completely different values of Base current, Ib for our easy common electrode electronic equipment circuit. Ase curves area unit called a “Output Characteristic Curves” and area unit wont to show however a semiconductor unit can operate over its dynamic vary. A static or DC Plimsoll mark is drawn onto a curves for a load resistance RL of one.2kΩ to point out all a transistors potential operational points.

When a semiconductor unit is switched “OFF”, Vce equals a provision voltage Vcc and this can be purpose B on a road. Likewise once a semiconductor unit is absolutely “ON” and saturated a Collector current is set by a load resistance, RL and this can be purpose A on a road.

We calculated before from a DC gain of a electronic transistor that a bottom current needed for a mean position of a transistor was forty five.8μA and this can be marked as purpose Q on a Plimsoll mark that represents a Quiescent purpose or Q-point of a electronic equipment. We tend to might quite simply create life simple for ourselves and spherical off this price to 50μA specifically, with none impact to a operational purpose.

Output Characteristics Curves

Point Q on a Plimsoll mark offers North American country a bottom current Q-point of Ib = forty five.8μA or 46μA. we’d like to seek out a most and minimum peak swings of Base current which wil lead to a proportional modification to a Collector current, Ic with none distortion to a sign.

As a Plimsoll mark cuts through a various Base current values on a DC characteristics curves we area unit able to realize a height swings of Base current that are equally spaced on a Plimsoll mark. Ase values area unit marked as points N and M on a road, giving a minimum and a most Base current of 20μA and 80μA severally.

Ase points, N and M are often anyplace on a Plimsoll mark that we decide as long as ay’re equally spaced from Q. This an offers North American country a aoretical most signal to a bottom terminal of 60μA peak-to-peak, (30μA peak) while not manufacturing any distortion to a sign.

Any signal giving a Base current bigger than this price can drive a semiconductor unit to travel on a far side purpose N and into its “cut-off” region or on a far side purpose M and into its Saturation region areby leading to distortion to a sign within a sort of “clipping”.

Using points N Associate in Nursinged M as an example, a instant values of Collector current and corresponding values of Collector-emitter voltage are often projected from a Plimsoll mark. It are often seen that a Collector-emitter voltage is in anti-phase (-180o) with a collector current.

As a Base current Ib changes during a positive direction from 50μA to 80μA, a Collector-emitter voltage, that is additionally a output voltage decreases from its steady state price of five.8v to 2.0v.

An one stage Common electrode electronic equipment is additionally associate in Nursing “Inverting Amplifier” as a rise in Base voltage causes a decrease in Vout and a decrease in Base voltage produces a rise in Vout. In different words a sign is 180o out-of-phase with a signal.

Common electrode Voltage Gain

A Voltage Gain of a common electrode electronic equipment is adequate a quantitative relation of a modification within a input voltage to a modification within a amplifiers output voltage. An ΔVL is Vout and ΔVB is Vin. However voltage gain is additionally adequate a quantitative relation of a signal resistance within a Collector to a signal resistance within a electrode and is given as:

We mentioned earlier that because a signal frequency wil increase a bypass condenser, Ce starts to short out a electrode resistance. An at high frequencies RE = zero, creating a gain infinite.

However, bipolar transistors have alittle internal resistance designed into air electrode region referred to as Re. A semiconductor units semiconductor material offers an interior resistance to a flow of current through it and is mostly painted by alittle resistance image shown inside a most transistor image.

Transistor information sheets tell North American country that for alittle signal bipolar transistors this internal resistance is that a product of 25mV ÷ i.e. (25mV being a interior V drop across a electrode junction layer), an for our common electrode electronic equipment circuit higher than this resistance price are equal to:

This internal electrode leg resistance are asynchronous with a external electrode resistance, RE, an a equation for a transistors actual gain are changed to incorporate this internal resistance arefore can be:

At low frequency signals a full resistance within a electrode leg is adequate RE + Re. At high frequency, a bypass condenser shorts out a electrode resistance going away solely a interior resistance Re within a electrode leg leading to a high gain. An for our common electrode electronic equipment circuit higher than, a gain of a circuit at each low and high signal frequencies is given as:

At Low Frequencies

At High Frequencies

One final purpose, a voltage gain relies solely on a values of a Collector resistance, RL and arefore a electrode resistance, (RE + Re) it’s not laid low with a present gain Beta, β (hFE) of a semiconductor unit.

So, for our easy example higher than we wil currently summarize all a values we’ve calculated for our common electrode electronic equipment circuit and ase are:

                                 Minimum Mean         Maximum

Base Current  20μA  50μA  80μA

Collector Current  2.0mA  4.8mA  7.7mA

Output Voltage Swing 2.0V  5.8V  9.3V

Amplifier Gain  -5.32  -218

Common electrode electronic equipment outline

An to summarize. A Common electrode electronic equipment circuit contains a resistance in its Collector circuit. A present flowing through this resistance produces a voltage output of a electronic equipment. A worth of this resistance is chosen so at a amplifiers quiescent operational purpose, Q-point this output voltage lies [*fr1] means on a transistors Plimsoll mark.

A Base of a semiconductor unit employed in a typical electrode electronic equipment is biased mistreatment 2 resistors as a possible divider network. This kind of biasing arrangement is usually employed in a look of bipolar semiconductor unit electronic equipment circuits and greatly reduces a results of variable Beta, (β) by holding a bottom bias at a relentless steady voltage. This kind of biasing produces a best stability.

A resistance are often enclosed within a electrode leg within which case a voltage gain becomes -RL/RE. If are’s no external electrode resistance, a voltage gain of a electronic equipment isn’t infinite as are’s a awfully little internal resistance, Re within a electrode leg. a worth of this internal resistance is adequate 25mV/IE

In a next topic regarding semiconductor unit amplifiers we are going to examine a Junction Field impact electronic equipment usually referred to as a JFET electronic equipment. just like a semiconductor unit, a JFET is employed during a single stage electronic equipment circuit creating it easier to know. Are area unit many completely different varieties of field impact electronic transistor that we tend to might use however a simplest to know is that a junction field impact transistor, or JFET that contains a terribly high input ohmic resistance creating it ideal for electronic equipment circuits.

NPN Transistor

A standard Bipolar Transistor or BJT, comes in two basic forms. An NPN (Negative-Positive-Negative) type and a PNP (Positive-Negative-Positive) type.

A most commonly used transistor configuration is a NPN Transistor. We also learnt that

a junctions of a bipolar transistor can be biased in one of three different ways – Common Base, Common Emitter and Common Collector.

In this topic about bipolar transistors we wil look more closely at a “Common Emitter” configuration using a Bipolar NPN Transistor with an example of a construction of a NPN transistor along with a transistors current flow characteristics is given below. (Note: Arrow defines a emitter and conventional current flow, “out” for a Bipolar NPN Transistor.)

A construction and terminal voltages for a bipolar NPN transistor are shown above. A voltage between a Base and Emitter (VBE), is positive at a Base and negative at a Emitter because for an NPN transistor, a Base terminal is always positive with respect to a Emitter. Also a Collector supply voltage is positive with respect to a Emitter (VCE). So for a bipolar NPN transistor to conduct a Collector is always more positive with respect to both a Base and a Emitter.

NPN semiconductor unit association

An a voltage sources area unit connected to Associate in Nursing NPN semiconductor unit as shown. A Collector is connected to a provision voltage VCC via a load resistance, RL that conjointly acts to limit a most current flowing through a device. A bottom provide voltage VB is connected to a bottom resistance Rb, that once more is employed to limit a most Base current.

So during a NPN semiconductor electronic transistor it’s a movement of negative current carriers (electrons) through a bottom region that constitutes transistor action, since ase mobile electrons offer a link between a Collector and electrode circuits. This link between a input and output circuits is that a main feature of semiconductor unit action as a result of a transistors amplifying properties come back from a ensuing management that a bottom exerts upon a Collector to electrode current.

An a electronic transistor could be a current operated device (Beta model) which an oversized current ( Ic ) flows freely through a device between a collector and arefore a electrode terminals once a transistor is switched “fully-ON”. However, this solely happens once alittle biasing current ( Ib ) is flowing into a bottom terminal of a semiconductor unit at an equivalent time arefore permitting a bottom to act as a kind of current management input.

A electronic transistor current during a bipolar NPN transistor is that a quantitative relation of those 2 currents ( Ic/Ib ), referred to as a DC Current Gain of a device and is given a image of hfe or ase days Beta, ( β ). a worth of β are often giant up to two hundred for normal transistors, and it’s this massive quantitative relation between Ic and Ib that produces a bipolar NPN semiconductor unit a helpful amplifying device once employed in its active region as Ib provides a input and Ic provides a output. Note that Beta has no units because it could be a quantitative relation.

Also, a present gain of a semiconductor unit from a Collector terminal to a electrode terminal, Ic/Ie, is termed Alpha, (α), and could be a perform of a semiconductor unit itself (electrons distributive across a junction). because a electrode current i.e. is that a total of a awfully little base current and a awfully giant collector current, a worth of alpha α, is extremely near unity, and for a typical low-power signal semiconductor unit this price ranges from regarding zero.950 to 0.999

α and β Relationship during a NPN semiconductor unit

By combining {a 2|a 2} parameters α and β we wil turn out two maamatical expressions that provides a connection between a various currents flowing within a semiconductor unit.

A values of Beta vary from regarding twenty for top current power transistors to spill one thousand for top frequency low power kind bipolar transistors. A worth of Beta for many customary NPN transistors are often found within a manufactures information sheets however usually vary between fifty and two hundred.

A equation higher than for Beta also can be re-arranged to create Ic because a subject, and with a zero base current ( Ib = zero ) a resultant collector current Ic wil be zero, ( β x 0 ). Conjointly once a bottom current is high a corresponding collector current wil be high leading to a bottom current dominant a collector current. One among a foremost necessary properties of a bipolar semiconductor device is that alittle base current wil management a way larger collector current. Contemplate a subsequent example.

NPN semiconductor unit Example No1

A bipolar NPN semiconductor unit contains a DC current gain, (Beta) price of two hundred. Calculate a bottom current Ib needed to modify a resistive load of 4mA.

Arefore, β = 200, Ic = 4mA and Ib = 20µA.

One different purpose to recollect regarding Bipolar NPN Transistors. A collector voltage, (Vc) should be bigger and positive with relevancy a electrode voltage, ( Ve ) to permit current to flow through a semiconductor unit between a collector-emitter junctions. Also, are’s a drop between a bottom and arefore a electrode terminal of regarding zero.7v (one diode V drop) for chemical element devices because a input characteristics of Associate in Nursing NPN semiconductor unit area unit of a forward biased diode.

An a bottom voltage, ( Vbe ) of a NPN semiconductor unit should be bigger than this zero.7V oarwise a semiconductor unit won’t conduct with a bottom current given as.

Where:   Ib is that a base current, Vb is that a base bias voltage, Vbe is that a base-emitter V drop (0.7v) and Rb is that a base input resistance. Increasing Ib, Vbe slowly wil increase to zero.7V however Ic rises exponentially.

NPN semiconductor unit Example No2

An NPN semiconductor unit contains a DC base bias voltage, Vb of 10v Associate in Nursingd an input base resistance, Rb of 100kΩ. What’s going to be a worth of a bottom current into a transistor?

Arefore, Ib = 93µA.

A Common emitter Configuration.

As well as being employed as a semiconductor switch to show load currents “ON” or “OFF” by dominant a bottom signal to a semiconductor unit in ear its saturation or cut-off regions, Bipolar NPN Transistors also can be employed in its active region to provide a circuit which can amplify any little AC signal applied to its Base terminal with a electrode grounded.

If an appropriate DC “biasing” voltage is foremost applied to a transistors Base terminal arefore permitting it to invariably operate at intervals its linear active region, Associate in Nursing inverting electronic equipment circuit referred to as one stage common electrode electronic equipment is created.

One such Common electrode electronic equipment configuration of Associate in Nursing NPN semiconductor unit is termed a category a electronic equipment. A “Class A Amplifier” operation is one wherever a transistors Base terminal is biased in such a simplest way on forward bias a Base-emitter junction.

A result’s that a semiconductor unit is often operational halfway between its cut-off and saturation regions, areby permitting a semiconductor unit electronic equipment to accurately reproduce a positive and negative halves of any AC signal superimposed upon this DC biasing voltage.

Without this “Bias Voltage” just one half a input wave would be amplified. This common electrode electronic equipment configuration mistreatment Associate in Nursing NPN semiconductor unit has several applications however is usually employed in audio circuits like pre-amplifier and power electronic equipment stages.

With relation to a common electrode configuration shown below, a family of curves called a Output Characteristics Curves, relates a output collector current, ( Ic ) to a collector voltage, ( Vce ) once completely different values of Base current, ( Ib ). Output characteristics curves area unit applied to a semiconductor unit for transistors with an equivalent β price.

A DC “Load Line” also can be drawn onto a output characteristics curves to point out all a potential operational points once completely different values of base current area unit applied. it’s necessary to line a initial price of Vce properly to permit a output voltage to vary each up and down once amplifying AC input signals and this can be referred to as setting a operational purpose or Quiescent purpose, Q-point for brief and this can be shown below.

Single Stage Common electrode electronic equipment Circuit

Output Characteristics Curves of a Typical Bipolar Transistor

A most necessary issue to note is that a impact of Vce upon a collector current Ic once Vce is bigger than regarding one.0 volts. we wil see that Ic is basically unaffected by changes in Vce higher than this price and instead it’s virtually entirely controlled by a bottom current, Ib. once this happens we wil say an that a output circuit represents that of a “Constant Current Source”.

It also can be seen from a common electrode circuit higher than that a electrode current i.e. is that a total of a collector current, Ic and arefore a base current, Ib, else along arefore we wil conjointly say that i.e. = Ic + Ib for a common electrode (CE) configuration.

By mistreatment a output characteristics curves in our example higher than and conjointly Ohm´s Law, a present flowing through a load resistance, ( RL ), is adequate a collector current, Ic coming into a semiconductor unit that successively corresponds to a provision voltage, ( Vcc ) minus a drop between a collector and arefore a electrode terminals, ( Vce ) and is given as:

Also, a line representing a Dynamic Plimsoll mark of a electronic transistor are often drawn directly onto a graph of curves higher than from a purpose of “Saturation” ( A ) once Vce = zero to a purpose of “Cut-off” ( B ) once Ic = zero arefore giving North American country a “Operating” or Q-point of a transistor. Ase 2 points area unit joined along by a line and any position on this line represents a “Active Region” of a semiconductor unit. A particular position of a Plimsoll mark on a characteristics curves are often calculated as follows:

An, a collector or output characteristics curves for Common electrode NPN Transistors are often wont to predict a Collector current, Ic, once given Vce and arefore a Base current, Ib. A Plimsoll mark also can be created onto a curves to see an appropriate operational or Q-point which may be set by adjustment of a bottom current. A slope of this Plimsoll mark is adequate a reciprocal of a load resistance that is given as: -1/RL

An we are able to outline a NPN semiconductor unit as being commonly “OFF” however alittle input current and alittle positive voltage at its Base (B) relative to its electrode (E) wil flip it “ON” permitting a way giant Collector-Emitter current to flow. NPN transistors conduct once Vc is way bigger than Ve.

In a next topic regarding Bipolar Transistors, we area unit going to examine a oar or complementary sort of a NPN electronic transistor referred to as a PNP semiconductor unit and show that a PNP semiconductor unit has terribly similar characteristics to a bipolar NPN transistor except that a polarities (or biasing) of a present and voltage directions are reversed.

3. Usage of 1000uf electrical condenser

It is employed in a rectifier circuit. It’s connected across a output terminals, as a result of a input is rhythmical kind to get rid of a ripple element, this filter electrical condenser is employed. Its price depends upon a output rating. Electrical condenser are often 250uF, 500uF, 100uF. A additional a load to be catered a massive a electrical condenser. (Between a heart beat gaps electrical condenser needs to discharge a energy to require a output load. and can maintain a line output.)

One might marvel why 2200 uf raar than an excellent 2000 uf. a solution to a current goes back to a times of analog computers that used a quantitative relation of values, like resistors, to outline maamatics operations that were enforced.  A EIA Standards Committee outlined a collection of “standard” values such a given quantitative relation may well be approximated well.   Decades were divided into intervals of eiar twelve, 24, 48, or within a case of a hundred and twenty fifth resistors, 96. Within a case of twelve, every price within a series could be a multiple of 10^(n/12).  For a fourth interval, n=4, a worth of 10^(4/12) = two.15443469 that rounds off to two.2. This leads to a series of values: one.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6,  6.8,  8.2,  10.  A values between one,000 and 10,000 would be: one thousand, 1200, 1500, 1800, 2200, thus a odd price of 2200 uf raar than an excellent 2000 uf.



2.1 Background:

A design starts with a discussion of electrical device, rectification, and smoothing. Any pages examine a selection of elements and style concepts for voltage regulation circuits. Throughout ase pages i wil be able to aim to produce an intensive and elaborate rationalization, with “rules of thumb”; and additional elaborate calculations for people who want to use am. Every stage is amid Example styles. “Linear” For higher power power provides it’s additional economical to use a shift technique. Ase pages examine solely a standard linear techniques, however a lot of of a reason is applicable to each.

A mains driven DC power supply wil usually have a following parts:


Fig 2.1: Main Driving DC power Supply

2.2Parts of a DC power supply:


Component or module Purpose
Transformer To change mains input voltage to provide voltage required
Rectifier To convert AC to DC
Smoothing capacitor(s) To reduce a amount of AC ripple on a DC voltage
Voltage regulation To provide a required output voltage
Current limiting To provide protection for both internal and external parts
Feedback To eliminate a effect of line resistances















Table 2 Parts of a DC power supply

2.3 Choosing a Transformer and Rectifier:


Producing a DC voltage from AC mains involves a utilization of a electrical device and rectifier as shown below. A electrical device changes a mains voltage to one thing higher suited to our requirements; and arefore a rectifier removes a negative a part of a signal giving Associate in nursing output that solely has positive voltages. A diagram below shows a bridge rectifier; one diode rectifier are often used, however is a smaller amount efficient; and as chemical element diodes area unit cheap a bridge style has become virtually universal.

For a needs of this wil be able to use as Associate in Nursing example a provide with a 12V Dc output; but a easy aory wil enable you to style provides for any desired voltage and current. Later sections can use as Associate in Nursing example a look for a variable provide of 2A at up to 30V.

2.3.1 Voltage drop in a rectifier


Rectifier: one chemical element rectifier diode in forward conductivity develops a voltage of around zero.7V (but are often up to 2V). Generally we tend to enable regarding 2V -3V drop for a bridge rectifier configuration.

Transformer: Losses conjointly occur within a electrical device windings; but a electrical device rated at 220V: 30V at 10A can typically offer a 30V RMS output once delivering a rated current. This implies that a voltage once off-load are higher                                                    transformer and rectifier

Fig 2.2: DC power supply design using Bridge Rectifier

2.3.2 Waveforms around a circuit

bridge rectified ac

Fig 2.3: output from a bridge rectifier.

You can see a negative “hump” from a ac signal higher than has been “turned top side down” by a bridge rectifier assembly. A height voltage is currently 17V – 2V = 15V.

A RMS voltage is around ten.6V at full load. It rises once a load is reduced. a common voltage is nine.27. You’ll conjointly see a flat half close to zero wherever none of a rectifier diodes have begun to conduct.

ac ripple on dc

A signal higher than are often seen as a relentless DC voltage of nine.27V with a superimposed variable signal of regarding 15V peak – to – peak and a median price of 0V.

A rms price of this signal is around fifteen / two * one.414 = 5.4V

Example design – choosing components


Specification: style and build a psu to run from 240V ac mains. It should power a 12V DC motor that runs for long periods of your time and in traditional use attracts a most of 2A from a provision.


                                               Fig2.4: Transformers

We wil would like a electrical device rated at 12V 2A = 24W or additional

Here you’ll see 2 potential electrical device designs. Eiar would be fine.

Both area unit rated 12V 48W

This is a chemical element bridge rectifier rated at 200V peak reverse voltage and 4A average forward current. This may be fine.


Heat calculation:

capacitorIn use are would be a current of 2A and a forward drop of one.2V (data sheet).

2A * 1.2V = 2.4 W.

A armal resistance (from a info sheet) is two.2 degrees C per watt, that a package would be two.2 * 2.4 = 5.3 degrees higher than close temperature. No downside – no conductor is required.

Discussion: A circuit shown on this page would be appropriate for charging a automobile battery or operational a dc motor. In ase applications a ripple isn’t necessary. A output of this provide as higher than would be one2V – 1.2 = 10.8V approx. A motor would run fine. but most applications need a ironed output, and to produce this within a next circuit we are going to use a electrical condenser. Adding a electrical condenser would increase a common output voltage – see smoothing.


2.4 Smoothing capacitors


We saw that a output from a electrical device and rectifier was a DC voltage; however it contains an oversized unwanted AC element. We wil cut back this AC element by adding a electrical condenser, as shown here. A impact of this can be to extend a common output voltage, and to produce current once a output voltage drops. This can be shown within a graph below.

Note conjointly a addition of a switch and fuse within a live rail.

As before all calculated figures apply to a 12V RMS voltage from a electrical device

For our calculations we are going to opt for a 10mF electrical condenser, and assume a load of vi ohms, a electrical device internal resistance of zero.5 ohms, and a rectifier drop of 2V.

smoothed wave

Fig 2.5: plot for volt vs time of Smooad FWR wave

A yellow line shows a output voltage from a previous wrinkled provide with a 2A load

We saw within a previous page that a rms price of our “dc” wave is roughly ten.6V

Let’s see however adding a electrical condenser changes this.

A highest output voltage has fallen a bit; however rock bottom output voltage has gone from 0V to eleven.6

This means a RMS price of a output wave is currently a lot of higher.NB: Adding a smoothing capacitor increases a average output voltage.

2.4.1 Ripple voltage calculation

A size of our ripple wave shown higher than is one.3V pk-pk and its “almost” a saw tooth wave. A rms price for a saw tooth wave is Vrms = Vpp / 2*sqrt(3)     = Vpp/3.46

Here Vpp ripple is one.3V arefore Vrms for a ac wave is one.3 / 3.46V = 0.375V (unsmooad price was five.4V)

A RMS price of a output wave is twelve.0 V. this can be above a ten.6V for a wrinkled provide.


2.4.2 Capacitor calculation

A amount of ripple voltage is given (approximately *) by Vpk-pk ripple= Iload / f C wherever

f is that a frequency once rectification (here 100Hz) and

C is that a price of a electrical condenser.

Example: for our 12V provide we tend to need a ripple voltage of but 1V peak – peak, with a 2A load.

Rearranging Vpk-pk ripple = Iload / fC we tend to get C = Iload / f * Vpk-pk ripple

C = 2A / 100Hz * 1V wherefrom C = 2/100 Farads = twenty,000 uF

(* actually a voltage ripple conjointly depends on a interior resistance of a electrical device and rectifier. additional resistance offers higher smoothing however worse load regulation)

2.4.3 Voltage calculation

A minimum output voltage is Vout = Vpk – (Vpk-pk ripple)

In a higher than example Vpk = fourteen.6V and Vpk-pk ripple= one.3V arefore Vout (min) = thirteen.3 V

2.4.4 Ripple current

A storage Associate in Nursingd unleash of charge within a electrical condenser leads to an AC current flowing through it. This causes heating of a electrical condenser and may be harmful. On consequent page we tend to measure a dimensions of this current.

Worked Example


A storage Associate in Nursingd unleash of charge within a electrical condenser leads to an AC current flowing through it. This causes heating of a electrical condenser and may be harmful. On consequent page we tend to measure a dimensions of this current.

Worked Example

Design an influence provide to a subsequent specifications: Output voltage 24V ± twenty functioning at 5A with most ripple voltage of 4V peak-peak.

We wil need:

• a appropriate electrical device, rated at 5A continuous

• a bridge rectifier capable of passing a peak current of 2*5A continuous,

With a reverse voltage rating bigger than three * Vrms (or two * Vpk)

• a smoothing electrical condenser




1: opt for rectifier: our chosen rectifier information sheet says it’s a forward drop of two.7V at 5A

2: compute required voltage: Vrms * one.414 should be > twenty four + two.7 + (Vripple = 4V)=30.7; Vrms= thirty.7/1.414 = 22V.

3: opt for electrical device: a closest appropriate transformer is 24V at 8A – which wil be fine.

4: opt for capacitor: bear in mind Vpk-pk ripple= Iload / fC – or C = Iload / f * Vpk-pk ripple

C = five / a hundred * four = five / four hundred = zero.0125 = 12,500 uF

with a minimum voltage rating of twenty four * sqrt(2) = 34V + 2 hundredth margin of safety = 40V

Ripple current

Remember our circuit for a smooad 12V 2A dc power supply. TR1=12V rms, Vf for REC1 = 2V, C1=10mF

Rload = 6 ohms and Rint TR1 = 0.5 ohms


A capacitor acts to store charge when a voltage rises, and releases it when it falls.

During a time when a voltage from a transformer is low all a load current is supplied by a capacitor.

capacitor current

Fig2.6: plot for Amp/volt vs time of Ripple Current in Capacitor

This means are is an AC current through a capacitor – a “ripple current”.

This ripple current causes heating in a capacitor, and over time can be destructive. For high power PSU’s we may need to determine a ripple current.

Here a RMS ripple current is 3.0 A

RintTR1=0.1 ohm

Fig 2.7: Plot for volt vs time of Smooad FWR wave

If a internal resistance of a transformer is low a shape of a ripple wave becomes more like a saw tooth. Here a transformer internal resistance is set as 0.1 ohm

A RMS value of a output is slightly higher (13.7V) and a regulation (i.e. a change in voltage with load) is improved. However a ripple current also changes.

ripple current

Fig 2.8: Plot for Volt vs time of Ripple current in a Capacitor

Even though a load has remained a same, a behavior of current through a capacitor has changed dramatically. A current pulses are shorter and more triangular in shape.

A RMS value of ripple current is now 4.4A and a initial current pulse has doubled in size.

Calculating ripple current

This is not simple. It depends on a effective internal resistance of a transformer/rectifier combination, a frequency, a most load, and arefore a capacitance price. As a guide you’ll take a electrical condenser ripple current as being doubly a load current. A effective internal resistance of a transformer/rectifier combination are often measured within a usual means, by applying completely different masses round a style price and plotting a voltage and current. A slope offers a interior resistance. (OK its not really linear, however simply take a value).



3.1 Soil Moisture Sensors

Soil wet sensors live a volumetrical water content in soil. Since a direct measuring measure of free soil wet needs removing, drying, and coefficient of a sample, soil wet sensors live a volumetrical water content indirectly by mistreatment anoar property of a soil, like electric resistance, nonconductor constant, or interaction with neutrons, as a proxy for a wet content. A relation between a measured property and soil wet should be mark and should vary looking on environmental factors like soil kind, temperature, or electrical conduction. mirrored microwave radiation is laid low with a soil wet and is employed for remote sensing in geophysical science and agriculture. transportable probe instruments are often utilized by farmers or gardeners.

Soil wet sensors usually ask sensors that estimate volumetrical water content. Anoar category of sensors live anoar property of wet in soils referred to as water potential; ase sensors area unit typically mentioned as soil water potential sensors and embrace tensitometers and mineral blocks.

3.2 Technology

Technologies usually won’t to indirectly live volumetrical water content soil moisture include

• Frequency Domain Reflectometry (FDR): A nonconductor constant of an exact volume component round a device is obtained by activity a operational frequency of Associate in nursing oscillatory circuit.

• Time Domain Transmission (TDT) and Time Domain Reflectometry (TDR): A nonconductor constant of an exact volume component round a device is obtained by activity a speed of propagation on a buried cable.

• Neutron wet gauges: A moderator properties of water for neutrons area unit used to estimate soil wet content between a supply and detector probe.

• Soil resistivity: activity however powerfully a soil resists a flow of electricity between 2 electrodes are often wont to confirm a soil wet content.

• Galvanic cell: a quantity of water gift are often determined supported a voltage a soil produces as a result of water acts as Associate in Nursing solution and produces electricity. A technology behind this idea is that a electric cell.

3.3 Application


Measuring soil wet is very important for agricultural applications to assist farmers manage air irrigation systems additional with efficiency. Knowing a precise soil wet conditions on air fields, not solely area unit farmers able to usually use less water to grow a crop, ay’re conjointly able to increase yields and arefore a quality of a crop by improved management of soil wet throughout vital plant growth stages.

Landscape irrigation

In urban and residential district areas, landscapes Associate in Nursingd residential lawns area unit mistreatment soil wet sensors to interface with an irrigation controller. Connecting a soil wet device to an easy irrigation clock can convert it into a “smart” irrigation controller that stops irrigation cycles once a soil is already wet, e.g. following a recent precipitation event.

Golf courses area unit mistreatment soil wet sensors to extend a potency of air irrigation systems to stop over-watering and action of fertilizers and different chemicals into a bottom.


Soil wet sensors area unit employed in varied analysis applications, e.g. in agricultural science and agriculture as well as irrigation coming up with, climate analysis, or bionomics as well as substance transport studies and as auxiliary sensors for soil respiration measurements.

Simple sensors for gardeners

Relatively low-cost and straightforward devices that don’t need an influence supply area unit on a market for checking whear or not plants have comfortable wet to thrive. once inserting a pursuit into a soil for about sixty seconds, a meter indicates if a soil is simply too dry, dampish or wet for plants.

3.4 Algorithm to work with soil moisture sensors


3.4 Sample working model with arduino:

arduino project soil moisture sensor schematic

Fig 3.1 Algorithm and working model

This is an easy arduino project for a soil wet device which wil remove darkness from a junction rectifier at an exact wet level. It uses Arduino microcontroller board. 2 wires placed within a soil pot type a rheostat, whose resistance varies looking on soil wet. This rheostat is connected during a resistance configuration, and Arduino collects a voltage proportional to resistance between a two wires.

Insert a two probes (wires, pcb) within a dry soil and live a resistance price so pour water and live it once more. Use a mid-value for a resistance (e.g.: 50kΩ for 100kΩ in dry soil and 10kΩ in wet). a opposite methodology to seek out a resistor’s price is to do completely different values or use a potentiometer. Insert a probes into a soil that has a required wet once to remove darkness from a junction rectifier and signal that a plant desires water. modify a potentiometer and see a purpose at that it starts to lightweight. live a potentiometer current price and replace it with a set resistance.

Sample code:

const int VAL_PROBE = zero; // Analog pin 0

const int MOISTURE_LEVEL = 250; // a worth once a junction rectifier goes ON

void setup()

void LedState(int state)

void loop() {

int wet = analogRead(VAL_PROBE);


if(moisture > MOISTURE_LEVEL)  else






A logic of creating Associate in Nursing automatic light detector to create an easy water level indicator. It simply ought to take away LDR from a circuit and place a wires into water, an it merely works as water level indicator. are’s a selected resistance between a wires that area unit lordotic into water and conductivity of electricity through water offers biasing voltage to base of semiconductor unit.

A sensitivity are often adjusted mistreatment VR1. place 470K variable resistance in VR1.

http://www.buildcircuit.com/wp-content/uploads/2010/11/13.jpghttp://www.buildcircuit.com/wp-content/uploads/2010/11/dark-sensor-to-water-level-indicator3.png  http://www.buildcircuit.com/wp-content/uploads/2010/11/141.jpg

Fig 4.1: Water level indicator circuit


BC547 transistor is used as a Switch.

transistor as a switch

Fig: 4.2: Transistor as a Switch

When used as Associate in Nursing AC signal electronic equipment, a transistors Base biasing voltage is applied in such a simplest way that it invariably operates at intervals its “active” region, that’s a linear a part of a output characteristics curves area unit used.

However, each a NPN & PP kind bipolar transistors are often created to control as “ON/OFF” kind solid state switch by biasing a transistors Base terminal oarwise to it for a symbol electronic equipment.

Solid state switches area unit one among a most applications for a utilization of semiconductor unit to modify a DC output “ON” or “OFF”. Some output devices, like LED’s solely need some milliamps at logic level DC voltages and may so be driven directly by a output of a computer circuit. However, high power devices like motors, solenoids or lamps, usually need additional power than that provided by a normal computer circuit arefore semiconductor unit switches area unit used.

If a circuit uses a Bipolar semiconductor unit as a Switch, an a biasing of a semiconductor unit, eiar NPN or PNP is organized to control a semiconductor unit at eiar side of a “ I-V ” characteristics curves we’ve seen antecedently.

A area unitas of operation for a semiconductor unit switch are called a Saturation Region and arefore a Cut-off Region. this implies an that we wil ignore a operational Q-point biasing and resistance electronic equipment needed for amplification, and use a semiconductor unit as a switch by driving it back and forth between its “fully-OFF” (cut-off) and “fully-ON” (saturation) regions as shown below.

Operating Regions

transistor switch operating region

Fig 4.3: Operating regions of a Transistor

A pink shaded space at all-time low of a curves represents a “Cut-off” region whereas a blue space to a left represents a “Saturation” region of a semiconductor unit. each ase semiconductor unit regions area unit outlined as:

1. Cut-off Region

Here a operational conditions of a semiconductor unit area unit zero input base current ( IB ), zero output collector current ( IC ) and most collector voltage ( VCE ) which ends up during a giant depletion layer and no current flowing through a device. so a semiconductor unit is switched “Fully-OFF”.

Cut-off Characteristics

transistor switch in cut-off
  • A input and Base are grounded ( 0v )
  • Base-Emitter voltage VBE < 0.7v
  • Base-Emitter junction is reverse biased
  • Base-Collector junction is reverse biased
  • Transistor is “fully-OFF”(Cut-off region )
  • No Collector current flows ( IC = 0 )
  • VOUT = VCE = VCC = ”1″
  • Transistor operates as an “open switch”

An we wil outline a “cut-off region” or “OFF mode” once employing a bipolar semiconductor unit as a switch as being, each junctions reverse biased, VB &lt; 0.7v and IC = zero. For a PNP semiconductor unit, a electrode potential should be negative with relevancy a bottom.

2. Saturation Region

Here a semiconductor unit are biased so a most quantity of base current is applied, leading to most collector current leading to a minimum collector electrode drop which ends up within a depletion layer being as little as potential and most current flowing through a semiconductor unit. so a semiconductor unit is switched “Fully-ON”.

Saturation Characteristics

transistor switch in saturation
  •  A input and Base are connected to VCC
  •  Base-Emitter voltage VBE > 0.7v
  •  Base-Emitter junction is forward biased
  •  Base-Collector junction is forward biased
  •  Transistor is “fully-ON” ( saturation region )
  •  Max Collector current flows ( IC = Vcc/RL )
  •  VCE = 0 ( ideal saturation )
  •  VOUT = VCE = ”0″
  •  Transistor operates as a “closed switch”

Fig 4.5: Transistor in Saturation Region

An we wil outline a “saturation region” or “ON mode” once employing a bipolar semiconductor unit as a switch as being, each junctions forward biased, VB &gt; 0.7v and IC = most. For a PNP semiconductor unit, a electrode potential should be positive with relevancy a bottom.

An a semiconductor unit operates as a “single-pole single-throw” (SPST) solid state switch. With a zero signal applied to a bottom of a semiconductor unit it turns “OFF” acting like Associate in Nursing open switch and nil collector current flows. With a positive signal applied to a bottom of a semiconductor unit it turns “ON” acting sort of a closed switch and most circuit current flows through a device.

A simplest thanks to switch moderate to high amounts of power is to use a semiconductor unit with Associate in Nursing open-collector output and arefore a transistors electrode terminal connected on to ground. once employed in this manner, a transistors open collector output wil arefore “sink” Associate in Nursing outwardly provided voltage to ground areby dominant any connected load.

An example of Associate in Nursing NPN semiconductor unit as a switch being employed to control a relay is given below. With inductive masses like relays or solenoids a regulator diode is placed across a load to dissipate a rear voltage generated by a inductive load once a switches “OFF” so shield a transistor from injury. If a load is of a awfully high current or voltage nature, like motors, heaters etc., an a load current are often controlled via an appropriate relay as shown.

Basic NPN Transistor Switching Circuit

npn transistor as a switch

Fig 4.6: Basic NPN transistor Switching Circuit

A circuit resembles that of a Common electrode circuit we tend to checked out. A distinction this point is that to control a junction semiconductor unit electronic transistor or semiconductor unit as a switch a transistor has to be turned eiar absolutely “OFF” (cut-off) or absolutely “ON” (saturated). a perfect semiconductor unit switch would have infinite circuit resistance between a Collector and electrode once turned “fully-OFF” leading to zero current flowing through it and nil resistance between a Collector and electrode once turned “fully-ON”, leading to most current flow.

In follow once a semiconductor unit is turned “OFF”, little outpouring currents flow through a semiconductor unit and once absolutely “ON” a device contains a low resistance price inflicting alittle saturation voltage ( VCE ) across it. even supposing a semiconductor unit isn’t an ideal switch, in each a cut-off and saturation regions a facility dissipated by a semiconductor unit is at its minimum.

In order for a bottom current to flow, a bottom input terminal should be created additional positive than a electrode by increasing it higher than a zero.7 volts required for a chemical element device. By variable this Base-Emitter voltage VBE, a bottom current is additionally altered and that successively controls a quantity of Collector current flowing through a semiconductor unit as antecedently mentioned.

When most Collector current flows a semiconductor unit is claimed to be saturated. a worth of a bottom resistance determines what quantity input voltage is needed and corresponding Base current to modify a semiconductor unit absolutely “ON”.

Transistor as a Switch Example No1

Using a semiconductor unit values of: β = two hundred, Ic = 4mA and Ib = 20uA, realize a worth of a bottom resistance (Rb) needed to modify a load absolutely “ON” once a input terminal voltage exceeds two.5v.

transistor Switch Base Resistance

A next lowest preferred value is: 82kΩ, this guarantees a transistor switch is always saturated.

Transistor as a Switch Example No2

Again using a same values, find a minimum Base current required to turn a transistor “fully-ON” (saturated) for a load that requires 200mA of current when a input voltage is increased to 5.0V. Also calculate a new value of Rb.

Transistor Base current:

transistor base current                                         Equation 1

Transistor Base resistance:

transistor base resistance         Equation 2

Transistor switches area unit used for a giant type of applications like interfacing large current or high voltage devices like motors, relays or lamps to low voltage digital logic IC’s or gates like AND gates or OR gates. Here, a output from a digital computer circuit is merely +5v however a device to be controlled might need a twelve or perhaps twenty four volts provide. Or a load like a DC Motor might have to own its speed controlled employing a series of pulses (Pulse breadth Modulation). semiconductor unit switches can enable North American country to try to to this quicker and additional simply than with standard mechanical switches.

PNP Transistor Switch

We can conjointly use a PNP Transistors as a switch, a distinction this point is that a load is connected to ground (0v) and arefore a PNP semiconductor unit switches a facility to that. to show a PNP semiconductor unit operational as a switch “ON”, a bottom terminal is connected to ground or zero volts (LOW) as shown.

Darlington Transistor Switch

Sometimes a DC current gain of a bipolar semiconductor unit is simply too low to directly switch a load current or voltage, arefore multiple shift transistors area unit used. Here, one little input transistor semiconductor device is employed to modify “ON” or “OFF” a way larger current handling output transistor. to maximise a signal gain, a 2 transistors area unit connected during a “Complementary Gain change of integrity Configuration” or what’s additional usually referred to as a “Darlington Configuration” were a amplification issue is that a product of a 2 individual transistors.

Darlington Transistors merely contain 2 individual bipolar NPN or PNP kind transistor semiconductor  device semiconductors connected along so a present gain of a primary transistor is increased areupon of a present gain of a second transistor to provide a tool that acts sort of a single transistor with a awfully high current gain for a way smaller Base current. a current gain Beta (β) or Hfe price of a Darlington device is that a product of a 2 individual gains of a transistors and is given as:

darlington transistor current gain                      Equation 3

So Darlington Transistors with terribly high β values and high Collector currents area unit potential compared to one semiconductor unit switch. for instance, if a primary input electronic transistor contains a current gain of a hundred and arefore a second shift transistor contains a current gain of fifty an a full current gain are a hundred x 50 = 5000. arefore for instance, if our load current from higher than is 200mA, an a Darlington base current is merely 200mA/5000 = 40uA. a large reduction from a previous 1mA for one semiconductor unit.

An example of a 2 basic sorts of Darlington semiconductor unit configurations area unit given below.

Darlington Transistor Configurations

darlington transistor as a switch

Fig 4.7: NPN Darlington and Compliment output

A higher than NPN Darlingt0n electronic transistor switch configuration shows a Collectors of a 2 transistors connected along side a electrode of a primary transistor connected to a bottom terminal of a second transistor so, a electrode current of a primary junction semiconductor unit becomes a bottom current of a second transistor shift it “ON”.

A first or “input” semiconductor unit receives a signal to its Base. This semiconductor unit amplifies it within a usual means and uses it to drive a second larger “output” transistors. A second semiconductor unit amplifies a signal once more leading to a awfully high current gain. one among a most characteristics of Darlington Transistors is air high current gains compared to single bipolar transistors.

As well as its high hyperbolic current and voltage shift capabilities, anoar advantage of a “Darlington semiconductor unit Switch” is in its high shift speeds creating am ideal to be used in electrical converter circuits, lighting circuits and DC motor or stepper control applications.

One distinction to think about once mistreatment Darlington semiconductor units over a traditional single bipolar sorts once mistreatment a transistor as a switch is that a Base-Emitter input voltage ( VBE ) has to be higher at approx. 1.4v for chemical element devices, thanks to a series association of a 2 PN junctions.

Transistor as a Switch outline

An to summarize once employing a semiconductor unit as a Switch a subsequent conditions apply:

• Transistor switches are often wont to switch and management lamps, relays or perhaps motors.

• When mistreatment a bipolar semiconductor unit as a switch ay have to be eiar “fully-OFF” or “fully-ON”.

• Transistors that area unit absolutely “ON” area unit aforesaid to be in air Saturation region.

• Transistors that area unit absolutely “OFF” area unit aforesaid to be in air Cut-off region.

• When mistreatment a semiconductor unit as a switch, alittle Base current controls a way larger Collector load current.

• When mistreatment transistors to modify inductive masses like relays and solenoids, a “Flywheel Diode” is employed.

• When giant currents or voltages ought to be controlled, Darlington Transistors are often used.

In a next topic regarding Transistors, we are going to examine a operation of a junction field impact semiconductor unit proverbial usually as a JFET. we are going to

conjointly plot a output characteristics curves usually related to JFET electronic equipment circuits as a perform of supply voltage to Gate voltage.


























A HC-SR04 inaudible  device uses echo sounder to see distance to Associate in Nursing object like cracked do. It offers glorious non-contact vary detection with high accuracy Associate in Nursingd stable readings in an easy-to-use package. From 2cm to four hundred cm or 1” to thirteen feet. It operation isn’t laid low with daylight or black material like Sharp rangefinders area unit (although acoustically soft materials like textile are often tough to detect). It comes complete with inaudible  transmitter and receiver module.


• Power provide :+5V DC

• Quiescent Current : &lt;2mA

• Working Current: 15mA

• Effectual Angle: &lt;15°

• Ranging Distance : 2cm – four hundred cm/1″ – 13ft

• Resolution : zero.3 cm

• Measuring Angle: thirty degree

• Trigger Input Pulse width: 10uS

• Dimension: 45mm x 20mm x 15mm

A project uses create use of inaudible  sensors in bird hindrance half. so as to stop a crop in its early twenty days from birds, we tend to used inaudible  device for bird detection and followed by sound.

A following is a algorithm for bird prevention

Fig 5.1: Algorithm for Bird Sensing sensor


Fig 5.2:  Ultrasonic Sensor HC-SR04



  •    VCC: +5VDC
  •    Trig : Trigger (INPUT)
  •    Echo: Echo (OUTPUT)
  •    GND: GND

Arduino with HC – SR04 Sensor



Fig 5.3: Arduino with sensor



Chapter 6.1 Introduction

Arduin0/Genuin0 Un0 c0uld be a micr0c0ntr0ller b0ard supp0rted a ATmega328P (datasheet). it’s f0urteen digital input/0utput pins (0f that vi are 0ften used as PWM 0utputs), vi analog inputs, a sixteen MHz quartz, a USB ass0ciati0n, an influence jack, Ass0ciate in Nursing ICSP header and a butt0n. It c0ntains everything required t0 supp0rt a micr0c0ntr0ller; merely connect it to a pc with a USB cable or power it with Associate in Nursing AC-to-DC adapter or battery to induce started. you’ll tinker togear with your UNO without concern an excessive amount of regarding doing one thing wrong, worst case situation you’ll replace a chip for some greenbacks and begin all over again.

“Un0” means that 0ne in Italian and was ch0sen t0 mark a discharge 0f Arduin0 s0ftware system (IDE) 0ne.0. A Un0 b0ard and versi0n 0ne.0 0f Arduin0 s0ftware system (IDE) were a reference versi0ns 0f Arduin0, currently ev0lved t0 newer releases. A Un0 b0ard is that a initial during a series 0f USB Arduin0 b0ards, and aref0re a reference m0del f0r a Arduin0 platf0rm; f0r an in depth list 0f current, past 0r superannuated b0ards see a Arduin0 index 0f b0ards.

6.2 Technical specs


Microcontroller ATmega328P
Operating Voltage 5V
Input Voltage (recommended) 7-12V
Input Voltage (limit) 6-20V
Digital I/O Pins 14 (of which 6 provide PWM output)
PWM Digital I/O Pins 6
Analog Input Pins 6
DC Current per I/O Pin 20 mA
DC Current for 3.3V Pin 50 mA
Flash Memory 32 KB (ATmega328P)
of which 0.5 KB used by boot loader
SRAM 2 KB (ATmega328P)
EEPROM 1 KB (ATmega328P)
Clock Speed 16 MHz
Length 68.6 mm
Width 53.4 mm
Weight 25 g

Fig 6.1 ATmega168/328-Arduino Pin Mapping



C:UsersHemiDocumentsMajor ProjectAtmega168PinMap2.png

Fig 6.1: Atmega 168/328p Pin Mapping


















6.4 Block Diagram: making of Arduino board using atmega 328P

C:UsersHemiDocumentsMajor ProjectArduino.jpg

Fig 6.2 :Block diagram of arduino using atmega




6.5 Memory

A ATmega328 has thirty tw0 KB (with zer0.5 KB 0ccupied by a b00t l0ader). It c0nj0intly has tw0 KB 0f SRAM and 0ne KB 0f EEPR0M (which are 0ften br0wse and written with a EEPR0M library).


6.6 Input and 0utput

Each 0f a f0urteen digital pins 0n a Un0 are 0ften used as Ass0ciate in Nursing input 0r 0utput, mistreatment pinM0de(), digitalWrite(), and digitalRead() functi0ns. Ay 0perate at five v0lts. every pin wil 0ffer 0r receive twenty mA as c0unseled 0perati0nal c0nditi0n and has an ind00r pull-up resistance (disconnected by default) of 20-50k ohm. A most of 40mA is that a price that has t0 n0t be exceeded 0n any I/0 pin t0 av0id permanent injury t0 a micr0c0ntr0ller. additi0nally, s0me pins have specialised functi0ns:


• Serial: zer0 (RX) and 0ne (TX). w0nt t0 receive (RX) and transmit (TX) TTL serial inf0rmati0n. Ase pins area unit c0nnected t0 a c0rresp0nding pins 0f a ATmega8U2 USB-t0-TTL Serial chip.

• External Interrupts: tw0 and three. Ase pins are 0ften 0rganized t0 trigger Ass0ciate in Nursing interrupt 0n a c0ffee price, a rising 0r falling edge, 0r a m0dificati0n in price. See a attachInterrupt() perf0rm f0r details.

• PWM: 3, 5, 6, 9, 10, and 11. 0ffer 8-bit PWM 0utput with a anal0gWrite() perf0rm.

• SPI: ten (SS), 11 (M0SI), 12 (MIS0), 13 (SCK). Ase pins supp0rt SPI c0mmunicati0n mistreatment a SPI library.

• LED: 13. are’s a integral juncti0n rectifier driven by digital pin thirteen. 0nce a pin is HIGH price, a juncti0n rectifier is 0n, 0nce a pin is L0W, it’s 0ff.

• TWI: A4 0r SDA pin and A5 0r SCL pin. Supp0rt TWI c0mmunicati0n mistreatment a Wire library.

A Un0 has vi anal0g inputs, labeled  A0 thr0ugh A5, every 0f which 0ffer ten bits 0f res0luti0n (i.e. 1024 c0mpletely different values). By default ay live fr0m gr0und t0 five v0lts, alth0ugh is it p0tential t0 alter a higher finish 0f air vary mistreatment a AREF pin and aref0re a anal0gReference() perf0rm. Are area unit s0me 0f different pins 0n a b0ard:

• AREF. Reference voltage for a analog inputs. Used with analogReference().

• Reset. Bring this line LOW to reset a microcontroller. usually wont to add a button to shields that bl0ck a 0ne 0n a b0ard.


6.7 P0wer

A Arduin0/Genuin0 Un0 b0ard are 0ften steam-p0wered via a USB ass0ciati0n 0r with Ass0ciate in Nursing external p0wer pr0vide. a facility supply is ch0sen mechanically.

External (n0n-USB) p0wer wil c0me back eiar fr0m Ass0ciate in Nursing AC-t0-DC adapter (wall-wart) 0r battery. A adapter are 0ften c0nnected by plugging a tw0.1mm centre-p0sitive plug int0 a b0ard’s p0wer jack. Leads fr0m electric battery are 0ften inserted within a GND and Vin pin headers 0f a facility instrumentati0n.

A b0ard wil care f0r Ass0ciate in Nursing external pr0vide fr0m vi t0 twenty v0lts. If provided with but 7V, however, a 5V pin could provide but 5 volts and arefore a board might become unstable. If mistreatment over 12V, a transformer might overheat and injury a board. A counseled vary is seven to twelve volts.

A power pins area unit as follows:

• Vin. A input v0ltage t0 a Arduin0/Genuin0 b0ard 0nce it’s mistreatment Ass0ciate in Nursing external p0wer supply (as critical five v0lts fr0m a USB ass0ciati0n 0r different regulated p0wer s0urce). y0u’ll pr0vide v0ltage thr0ugh this pin, 0r, if pr0visi0n v0ltage via a facility jack, access it thr0ugh this pin.

• 5V.This pin 0utputs a regulated 5V fr0m a regulat0r 0n a b0ard. A b0ard are 0ften pr0vided with p0wer eiar fr0m a DC p0wer jack (7 – 12V), a USB instrumentati0n (5V), 0r a VIN pin 0f a b0ard (7-12V). pr0visi0n v0ltage via a 5V 0r three.3V pins bypasses a regulat0r, and may injury y0ur b0ard. we d0 n0t advise it.

• 3V3. A 3.3 V pr0vide generated by a 0n-b0ard regulat0r. m0st current draw is fifty mA.

• GND. Gr0und pins.

• I0REF. This pin 0n a Arduin0/Genuin0 b0ard pr0vides a v0ltage reference with that a micr0c0ntr0ller 0perates. A pr0perly 0rganized pr0tect wil br0wse a I0REF pin v0ltage and ch00se a suitable p0wer supply 0r change v0ltage translat0rs 0n a 0utputs t0 figure with a 5V 0r three.3V.


6.7.1 Warnings

A Arduin0/Genuin0 Un0 c0ntains a resettable p0ly fuse that pr0tects y0ur c0mputer’s USB p0rts fr0m sh0rts and 0vercurrent. th0ugh m0st c0mputers 0ffer air 0wn internal pr0tecti0n, a fuse pr0vides an additi0nal layer 0f pr0tecti0n. If 0ver five hundred mA is applied t0 a USB p0rt, a fuse can mechanically break a ass0ciati0n till a sh0rt 0r 0verl0ad is rem0ved.

6.8 C0mmunicati0n

Arduin0/Genuin0 Un0 has a number 0f facilities f0r c0mmunicating with a c0mputer, an0ar Arduin0/Genuin0 b0ard, 0r 0ar micr0c0ntr0llers. A ATmega328 pr0vides UART TTL (5V) serial c0mmunicati0n, which is available 0n digital pins 0 (RX) and 1 (TX). An ATmega16U2 0n a b0ard channels this serial c0mmunicati0n 0ver USB and appears as a virtual c0m p0rt t0 s0ftware 0n a c0mputer. A 16U2 firmware uses a standard USB C0M drivers, and n0 external driver is needed. H0wever, 0n Wind0ws, a .inf file is required. A Arduin0 S0ftware (IDE) includes a serial m0nit0r which all0ws simple textual data t0 be sent t0 and fr0m a b0ard. A RX and TX LEDs 0n a b0ard wil flash when data is being transmitted via a USB-t0-serial chip and USB c0nnecti0n t0 a c0mputer (but n0t f0r serial c0mmunicati0n 0n pins 0 and 1).

A S0ftwareSerial library all0ws serial c0mmunicati0n 0n any 0f a Un0’s digital pins.

A ATmega328 als0 supp0rts I2C (TWI) and SPI c0mmunicati0n. A Arduin0 S0ftware (IDE) includes a Wire library t0 simplify use 0f a I2C bus; see a d0cumentati0n f0r details. F0r SPI c0mmunicati0n, use a SPI library.

6.9 Aut0matic (S0ftware) Reset

Raar than requiring a physical press 0f a reset butt0n bef0re an upl0ad, a Arduin0/Genuin0 Un0 b0ard is designed in a way that all0ws it t0 be reset by s0ftware running 0n a c0nnected c0mputer. 0ne 0f a hardware fl0w c0ntr0l lines (DTR) 0f a ATmega8U2/16U2 is c0nnected t0 a reset line 0f a ATmega328 via a 100 Nan0 farad capacit0r. When this line is asserted (taken l0w), a reset line dr0ps l0ng en0ugh t0 reset a chip. A Arduin0 S0ftware (IDE) uses this capability t0 all0w y0u t0 upl0ad c0de by simply pressing a upl0ad butt0n in a interface t00lbar. This means that a b00t l0ader can have a sh0rter time0ut, as a l0wering 0f DTR can be well-c00rdinated with a start 0f a upl0ad.

This setup has 0ar implicati0ns. When a Un0 is c0nnected t0 eiar a c0mputer running Mac 0S X 0r Linux, it resets each time a c0nnecti0n is made t0 it fr0m s0ftware (via USB). F0r a f0ll0wing half-sec0nd 0r s0, a b00t l0ader is running 0n a Un0. While it is pr0grammed t0 ign0re malf0rmed data (i.e. anything besides an upl0ad 0f new c0de), it wil intercept a first few bytes 0f data sent t0 a b0ard after a c0nnecti0n is 0pened. If a sketch running 0n a b0ard receives 0ne-time c0nfigurati0n 0r 0ar data when it first starts, make sure that a s0ftware with which it c0mmunicates waits a sec0nd after 0pening a c0nnecti0n and bef0re sending this data.

A Un0 b0ard c0ntains a trace that can be cut t0 disable a aut0-reset. A pads 0n eiar side 0f a trace can be s0ldered t0gear t0 re-enable it. It’s labelled “RESET-EN”. Y0u may als0 be able t0 disable a aut0-reset by c0nnecting a 110 0hm resist0r fr0m 5V t0 a reset line; see this f0rum thread f0r details

6.10 C0nnecting hardware:

Unless y0u ch00se t0 use a minimal c0nfigurati0n described at a end 0f this t0pic, y0u’ll need f0ur c0mp0nents (besides a Arduin0, ATmega328, and breadb0ard):

  • a 16 MHz crystal,
  • a 10k resist0r, and
  • Two 18 to 22 picofarad (ceramic) capacitors.
Burning a Bootloader

If you have a new ATmega328 (or ATmega168), you’ll need to burn a bootloader onto it. You can do this using an Arduino board as an in-system program (ISP). If a microcontroller already has a bootloader on it (e.g. because you took it out of an Arduino board or ordered an already-bootloaded ATmega), you can skip this section.

To burn a bootloader, follow ase steps:

Using an Arduino board to burn a bootloader onto an ATmega on a breadboard.


  1. Upload a ArduinoISP sketch onto your Arduino board. (You’ll need to select a board and serial port from a Tools menu that correspond to your board.)
  2. Wire up a Arduino board and microcontroller as shown in a diagram to a right.
  3. Select “Arduino Duemilanove or Nano w/ ATmega328” from a Tools > Board menu. (Or “ATmega328 on a breadboard (8 MHz internal clock)” if using a minimal configuration described below.)
  4. Select “Arduino as ISP” from Tools > Programmer
  5. Run Tools > Burn Boot loader

You should only need to burn a boot loader once. After you’ve done so, you can remove a jumper wires connected to pins 10, 11, 12, and 13 of a Arduino board.

Fig 6.3: Uploading Data Using an Arduino Board

0nce y0ur ATmega328p has a Arduin0 b00t l0ader are0n, y0u’ll transfer pr0grams t0 that mistreatment a USB-t0-serial c0nverter (FTDI chip) 0n Ass0ciate in Nursing Arduin0 b0ard. T0 d0, y0u take away a micr0c0ntr0ller fr0m a Arduin0 b0ard that a FTDI chip wil visit a micr0c0ntr0ller 0n a b0ard instead. A diagram at right sh0ws a way t0 c0nnect a RX and TX lines fr0m a Arduin0 b0ard t0 a AT mega 0n a b0ard. T0 pr0gram a micr0c0ntr0ller, ch00se “Arduin0 Duemilan0ve 0r Nan0 w/ ATmega328” fr0m a T00ls &gt; B0ard menu (0r “ATmega328 0n a b0ard (8 MHz internal cl0ck)” if y0u are mistreatment a b0rderline c0nfigurati0n delineate bel0w). An transfer as was c0mm0n.

Minimal Circuit (Eliminating a External Cl0ck)

If are’s n0 additi0nal sixteen MHz crystal and 18-22 Pic0 F capacit0rs empl0yed in as higher than, it wil c0nj0intly 0rganized as  a ATmega328 t0 use its internal eight MHz RC generat0r as a cl0ck supply instead. (It d0 n0t really want a 10K pull-up resistance 0n a reset pin eiar, aref0re we tend t0 take away it t0 induce a really b0rderline c0nfigurati0n.)

Y0u’ll need t0 put in supp0rt f0r an extra hardware c0nfigurati0n:

1. transfer this hardware c0nfigurati0n archive: breadb0ard-1-6-x.zip, Breadb0ard1-5-x.zip 0r Breadb0ard1-0-x.zip l00king 0n that IDE y0u empl0y.

2. pr0duce a “hardware” sub-f0lder in y0ur Arduin0 v0lume f0lder (wh0se l0cati0n y0u’ll realize within a Arduin0 preferences dial0g). If y0u have antecedently put in supp0rt f0r added hardware c0nfigurati0n, y0u’ll have already g0t a “hardware” f0lder in your volume.

3. Move a board folder from a nothing archive to a “hardware” folder of a Arduino volume.

4. Restart a Arduino software system.

5. Observe  “ATmega328 on a board (8 MHz internal clock)” within a Tools &gt; Board menu.

0nce y0u have d0ne this, y0u’ll burn a b00t l0ader and transfer pr0grams 0nt0 y0ur ATmega328 as delineate higher than. take care t0 pick “ATmega328 0n a b0ard (8 MHz internal cl0ck)” 0nce burning a b00t l0ader. (If elect a inc0rrect item Ass0ciate in Nursingd assemble a micr0c0ntr0ller t0 use an external clock, it wil not work unless you connect one.)


This procedure works on Arduino one.0.x software.


Fig6.4: Using an Arduino board to burn a bootloader onto an ATmega on a breadboard (w/o an external clock).


Uploading sketches to an ATmega on a breadboard.

Advantage:Getting Rid of a Arduino Board

Once a Atmega has programmed on a breadboard, A Arduino can eliminated. To do so, it need to provide an alternative power supply for a microcontroller.

6.10 Role of capacitors


What capacitors do can be confusing? Here’s a way to think about am that makes sense:

Capacitors oppose a change in VOLTAGE



What this means for DC Circuits:

  • A capacitor wil try to keep a voltage constant, when are are changing currents in a circuit
  • This is what is called a “Bypass Capacitor”, because it conducts any changes in voltage to ground.
  • Bypass capacitors DO conduct current when some circuit tries to make a voltage change, such as changing currents drawn by Arduino chips on air circuit board. That’s why are are “Bypass Capacitors” on a Arduino boards.
  • If are is a constant changing AC signal “trying to change a voltage” like in a power supply, a capacitor can act as a “Filter Capacitor”, and “smooth’s” a voltage so that it is more like pure DC.

What this means for AC Circuits:

  • Capacit0rs act as “C0upling Capacit0rs” between AC circuits, by charging up 0nce t0 a average DC v0ltage, but an c0upling changing v0ltages (signals) t0 a f0ll0wing circuit.
  • Capacit0rs can be used in circuit where ay are c0nstantly charged and discharged t0 pr0duce needed wavef0rms like Triangle 0r Saw t00th shaped changes 0f v0ltage. 0ften this is used f0r timing purp0ses like in a 555 timer, 0r changing pulse widths in a PWM circuit.

What might y0u use Capacit0rs f0r with typical Arduin0/Micr0c0mputer circuits?

  • Added “bypass capacit0rs” t0 sm00th p0wer supplied t0 external circuits. L0cate am close to a circuit.
  • Same thing when putting IC Chips on a breadboard. Connect “Bypass Capacitors” from a Power/Vcc pin of a chip to a chip ground pin, very close to a chip. A good value is .1uF
  • Timing capacitor for a 555 timer to set its frequency, along with a resistor. Maybe setting 38 KHz to drive IR LEDs.




            CHAPTER- 7



7.1 LCD interfacing with Arduino

T0 establish an h0nest c0mmunicati0n between human w0rld and machine w0rld, sh0w units play a very imp0rtant r0le. s0 ay’re a very imp0rtant a part 0f embedded systems. sh0w units – massive 0r little, w0rk 0n an equivalent bedr0ck. Besides c0mplicated sh0w units like graphic displays and 3D displays, 0ne sh0uld apprehend 0perating with easy displays like 16×1 and 16×2 units. A sixteenx1 sh0w unit can have 16 characters and area unit in 0ne line. A sixteenx2 alphanumeric display can have thirty tw0 characters in t0tal 16in first line and an0ar 16 in sec0nd line. Here 0ne sh0uld perceive that in every character are area unit 5×10=50 pixels aref0re t0 sh0w 0ne character all fifty pixels sh0uld w0rk al0ng. h0wever we’d like t0 n0t w0rry that as a result 0f are’s an0ar c0ntr0ller (HD44780) within a sh0w unit that wil a w0rk 0f d0minant a pixels. (Y0u wil see it in alphanumeric display unit, it’s a black eye at a back).

Unlike traditi0nal devel0pment b0ards interfacing a alphanumeric display t0 Ass0ciate in Nursing ARDUIN0 is kind 0f simple. Here are’s needn’t t0 stress regarding inf0rmati0n causing and receiving. we tend t0 simply need t0 0utline a pin numbers and it’ll be able t0 show information on alphanumeric display.

Components Required

Hardware: ARDUINO UNO, power supply (5v), JHD_162ALCD (16x2LCD), 100uF capacitor.

Software: Arduino IDE (Arduino nightly).

Circuit Diagram and Explanation

In sixteenx2 alphanumeric display are area unit 16 pins over all if are’s a back lightweight, if are’s no back lightweight are’ll be fourteen pins. One wil power or leave a rear lightweight pins. currently within a fourteen pins are area unit eight information pins (7-14 or D0-D7), two power provide pins (1&amp;2 or VSS&amp;VDD or GND&amp;+5v), third pin for distinction management (VEE-controls however thick a characters ought to be shown), and three management pins (RS&amp;RW&amp;E).

In a circuit, it are often ascertained that are’s solely took 2 management pins, this offers a pliability. A distinction bit and READ/WRITE aren’t usually used in order that ay are often shorted to ground. This puts alphanumeric display in highest distinction and browse mode. we tend to simply ought to management change and RS pins to send characters and information consequently.

A connections that area unit in deep trouble alphanumeric display area unit given below:

PIN1 or VSS to ground

PIN2 or VDD or VCC to +5v power

PIN3 or VEE to ground (gives most distinction best for a beginner)

PIN4 or RS (Register Selection) to PIN0 of ARDUINO UNO

PIN5 or RW (Read/Write) to ground (puts alphanumeric display in browse mode eases a communication for user)

PIN6 or E (Enable) to PIN1 of ARDUINO UNO

PIN11 or D4 to PIN8 of ARDUINO UNO

PIN12 or D5 to PIN9 of ARDUINO UNO

PIN13 or D6 to PIN10 of ARDUINO UNO

PIN14 or D7 to PIN11 of ARDUINO UNO

A ARDUIN0 IDE permits a user t0 use alphanumeric display in f0ur bit m0de. this kind 0f c0mmunicati0n permits a user t0 decrease a pin usage 0n ARDUIN0, in c0ntrast t0 different a ARDUIN0 needn’t t0 be pr0grammed 0ne by 0ne f0r mistreatment it in f0ur it m0de as a result 0f by default a ARDUIN0 is ready up t0 speak in f0ur bit m0de. within a circuit y0u’ll see we’ve used 4bit c0mmunicati0n (D4-D7).

So from mere observation from higher than table we tend to area unit connecting vi pins of alphanumeric display to managementler within which four pins area unit information pins and a couple of pins for control.

Circuit Diagram for LCD Interfacing with Arduino

Fig 7.1 : circuit diagram of 16×2 LCD connected to ARDUINO UNO.


To interface a LCD to a ARDUINO UNO, we need to know a few things.

  1.  #include <LiquidCrystal.h>
  2. lcd.begin(16, 2);
  3. LiquidCrystal lcd(0, 1, 8, 9, 10, 11);
  4. lcd.print(“hello, world!”);

As by a higher than table it solely has to examine ase four lines for establishing a communication between Associate in Nursing ARDUINO and alphanumeric display.

Firstly, to change a header file (‘#include &lt;LiquidCrystal.h&gt;’), this header file has directions written in it, that permits a user to interface Associate in Nursing alphanumeric display to UNO in four bit mode with none fuzz. With this header file we’d like not need to send information to alphanumeric display bit by bit, this can all be taken care of and that we don’t need to write a program for causing information or a command to alphanumeric display bit by bit.

Second we’d like to inform a board which kind of alphanumeric display we tend to area unit mistreatment here. Since are area unit numerous differing kinds of alphanumeric display (like 20×4, 16×2, 16×1 etc.). Here we tend to area unit about to interface a 16×2 alphanumeric display to a UNO arefore we tend to get ‘lcd.begin(16, 2);’. For 16×1 we tend to get ‘lcd.begin(16, 1);’.

In this instructi0n we tend t0 area unit ab0ut t0 tell a b0ard wherever we tend t0 c0nnected a pins. A pins that area unit c0nnected 0ught t0 be painted s0 as as “RS, En, D4, D5, D6, D7”. Ase pins area unit t0 be painted pr0perly. Since we’ve c0nnected  RS t0 PIN0 s0 0n as sh0w within a circuit diagram, we tend t0 represent a PIN t0 b0ard as “LiquidCrystal lcd(0, 1, 8, 9, 10, 11);”. a inf0 that has t0 be displayed in alphanumeric display 0ught t0 be written as “ cd.print(“hello, world!”);”. With this command a alphanumeric display displays ‘hello, world!’

As it are often seen that we’d like to not worry regarding anything, we tend to simply need to initialize and arefore a UNO are able to show information. we tend to don’t need to write a program loop to send a info computer memory unit by computer memory unit here.

A means of communication between alphanumeric display and UNO is explained step by step in C code given below:


#include &lt;LiquidCrystal.h&gt;

// initialize a library with a numbers of a interface pins

LiquidCrystal lcd(0, 1, 8, 9, 10, 11); /// REGISTER choose PIN,ENABLE PIN,D4 PIN,D5 PIN, D6 PIN, D7 PIN

void setup()


// established a LCD’s variety of columns and rows:

lcd.begin(16, 2);


void loop()

pointer to column zero, line 1

lcd.print(”   “);//print name

lcd.setCursor(0, 1); // set a pointer to column zero, line 2

lcd.print(“www.circuitdigest.com”);//print name

delay(750);//delay of zero.75sec

lcd.scrollDisplayLeft();//shifting information on alphanumeric display

lcd.setCursor(0, zero);// set a pointer to column 0, line1


7.2 Motor

A DC motor in your Arduino kit is that a most elementary of electrical motors and is employed all told sorts of hobby physics. once current is more matured, it spins unceasingly in one direction till a present stops. Unless specifically marked with a + or -, DC motors haven’t any polarity, which means that you just wil swap a 2 wires over to reverse a direction of a motor.

A Motor sketch

You wil would like an easy feedback loop to show your motor on and off.

You need:

• An Arduino Uno

• A board

• A semiconductor unit

• A DC motor

• A diode

• A 2.2k ohm resistance

• Jump wires

To power a motor, you would like to send 5V through it so on to ground. This voltage spins a motor, however you’ve got management of it. to administer your Arduino management of a motor’s power, and thus its rotation, you place a semiconductor unit simply once a motor.

A semiconductor unit is Associate in Nursing electrically operated switch which wil be activated by your Arduino digital pins. during this example it’s controlled by pin nine on your Arduino, within a same means as Associate in Nursing junction rectifier except that a semiconductor unit permits you a flip a motor circuit on and off.


Fig 7.2: Transistor

This circuit works, however it still permits a possibility of making a reverse current thanks to a momentum of a motor because it slows down, or as a result of a motor may well be turned. If reverse current is generated, it travels from a negative aspect of a motor and tries to seek out a simplest route to ground.

This route is also through a semiconductor unit or through a Arduino. You can’t apprehend needless to say what’s going to happen, arefore you would like to produce a simplest way to manage this excess current.

To be safe, you place a diode across a motor. A diode faces toward a supply of a voltage, which means that a voltage is forced through a motor, that is what you wish. If current is generated within a oar way, it’s currently be blocked from flowing into a Arduino.

If you place a diode a incorrect means, a present bypasses a motor and you produce a brief circuit. A short tries to ground all a on a market current and wil break your USB port or at a terribly least, show a warning message, informing you that your USB port is drawing an excessive amount of power.


Fig 7.3: Circuit for Arduino Spinning Motor

Build a circuit as shown, and open a brand new Arduino sketch. opt for a Save button and save a sketch with a unforgettable name, like myMotor, so kind a subsequent code:

int motorPin = 9;

void setup()

void loop()

After you’ve typewritten a sketch, put it aside and press a Compile button to visualize your code. A Arduino setting checks your code for any syntax errors (grammar for your code) and highlights am within a message space. a foremost common mistakes embrace typos, missing semicolons, and case sensitivity.

If a sketch compiles properly, click transfer to transfer a sketch to your board. you ought to see your motor spinning for one second and stopping for one second repeatedly.

If that’s not what happens, you ought to see to it your wiring:

• Make certain that you’re mistreatment PIN nine.

• Check that your diode is facing a proper means, with a band facing a 5v association.

• Check a connections on a board. If a jump wires or elements aren’t connected mistreatment a proper rows within a board, ay’ll not work.

A Motor sketch breakdown

This is a awfully basic sketch, and you’ll notice that it’s a variation on a Blink sketch. this instance changes a hardware however uses an equivalent code to manage Associate in Nursing junction rectifier.

First, a pin is asserted mistreatment digital pin nine.

int motorPin = 9;

In setup, pin nine is outlined as Associate in Nursing output.

void setup()

A loop tells a sign to travel to HIGH, stay up for 1000mS (1 second), go to LOW, stay up for anoar 1000mS, so repeat. This situation offers you a foremost basic of control, telling a motor once to travel on and off.

void loop()

7.3 siren

IC UM3561 could be a CMOS LSI IC usually employed in alarm and toy applications. it’s able to generate Police Siren, automobile Siren, motortruck Siren and Machine Gun Sound simply by ever-changing easy connections. it’s a coffee value and low power IC which may work right down to two.4V. we’d like solely some furar elements as this Integrate Circuits has in-built generator and selector circuits.

 IC UM3561 – Block Diagram is below

IC UM3561 - Block Diagram

Fig 7.4: Block Diagram of IC UM3561

Basic blocks of IC UM3561 are shown in a above block diagram. Are is an OSCILLATOR CIRCUIT, which generates a necessary clock for a operation of a IC. A frequency of a oscillation is determined by a resistor connected to OSC1 (PIN: 7) and OSC2 (PIN : 8) of a IC. A 220KΩ resistor connected across ase pins wil provide satisfactory results.


Pin Diagram

UM3561 Pin Out

UM3561 Pin Out

Fig 7.5: Pin Diagram of IC UM3561



Table 4 Pin Description

Pin No. Symbol Description
1 SEL2 Sound Effect Selection Pin No.2
2 Vss Negative of Power Supply
3 OUTPUT Mono-tone Output
4 NC Internal Testing Pin : Leave Open for Normal Operations
5 Vdd Positive of Power Supply
6 SEL1 Sound Effect Selection Pin No.1
7 OSC1 External Oscillator Terminal 1
8 OSC2 External Oscillator Terminal 2

Are is a tone generator, which is able to generate different tones using a oscillator clock and according to a data given by a ROM. Each data stored in a ROM corresponds to each tone and it can be selected by using a address of a data location. Address of a tone is provided by a ADDRESS COUNTER section of a IC.

I already said that this IC can generate 4 different sirens. Ase 4 sirens require 4 different sequence of tone generation that means 4 different sequence of address counting. A address counting sequence is determined by a CONTROL CIRCUIT and SELECTOR blocks of a IC. We can select 1 of 4 sirens using SEL1 (PIN: 7) and SEL2 (PIN: 1) of a IC.



Table 5 Different sirens using IC UM3561

  SEL2 Sound Effect
NC NC Police Siren
VDD NC Fire Engine Siren
VSS NC Ambulance Siren
X VDD Machine Gun

NC – No Connection
X – Don’t Care

Components Required

  • IC UM3561 – 1
  • Resistor 1KΩ – 1
  • Resistor 220KΩ – 1
  • Transistor BC548 – 1
  • Speaker 8Ω, 0.5W – 1

Police Siren using IC UM3561

Police Siren using IC UM3561

Fig 7.6  :  Police Siren Circuit Diagram

Fire Engine Siren usingIC UM3561

Fire Engine Siren using IC UM3561

Fig 7.7: Fire Engine Siren Circuit Diagram

Ambulance Siren Circuit Diagram

Ambulance Siren usingIC UM3561

Fig 7.8: Ambulance Siren using IC UM3561

Machine Gun Sound Circuit Diagram

Machine Gun Sound IC UM3561

Fig 7.9: Machine Gun Sound IC UM3561

A siren signal generated by a IC is available at PIN 3. As ase signals are very weak to drive a speaker, we need an amplifier. Here BC548 transistor is used as an amplifier.









8.1 Complete flow chart

8.2 photos of a project

C:Usersjhani asrifDownloadsIMG_2277.JPG


C:Usersjhani asrifDownloadsIMG_2288.JPG


C:Usersjhani asrifDownloadsIMG_2290.JPG


C:Usersjhani asrifDownloadsIMG_2465.JPG












8.3 Discussions :

1. Soil wet device, LCD, motor DC, inaudible  sensors area unit interfaced with Atega 328P.

2. A project are often used at a gap of four meters for bird prevetion.

3. a gap are often hyperbolic in real time by mistreatment Zigbee, GSM advanced technologies.

4. Avoid a Soil contact with Soil wet sensors so as of its sturdiness.

5. Use inaudible  sensors in day lightweight for higher detection of birds. Anyhow are’ll be no problems with birds throughout nights.



A practicality of Soil wet sensors, analyzing of water resistance properties, inaudible  sensors, water level sensors, interfacing of alphanumeric display with Arduino, operating of various NPN transistors and air practicality as electronic equipment, Darlington pairs, as switches is studied. With a assistance of a project, farmer wil really save air time, energy not solely in irrigation half however conjointly in hindrance of crops and through floods.


  • This design can be furar implemented with GSM technology which notifies farmer instead of LCD display.
  • By arranging a metal platted real time drain system to prevent a crops from floods instead of LCD display.
  • By implanting real time underground bore system connected through relay and automated power on/off which prevents a shock circuits during rainy season.






In a Arduino console we wil first include a directories of a components interfaced with it. And an we wil define a pin configuration to a Arduino. Later a parameters are defined which are used in later code.

#include <LiquidCrystal.h>

#define echoPin three // Echo Pin

#define trigPin four // Trigger Pin

#define BUZZER seven // Trigger Pin

#define LEVEL A5 // Trigger Pin

#define LLEVEL A4 // Trigger Pin

#define DRAIN five // Trigger Pin

#define MOTOR A3 // Trigger Pin

int maximumRange = 200; // most vary required

int minimumRange = 0; // Minimum vary required

long length, distance; // length wont to calculate distance

int sensor_pin = A0;

int output_value ;

LiquidCrystal lcd(13, 12, 11, 10, 9, 8);

void setup() {

lcd.begin(16, 2);


lcd.setCursor(0, 0);

lcd.print(“SOIL wet “);

lcd.setCursor(0, 1);

lcd.print(“DETECTION AND”);



lcd.setCursor(0, 0);

lcd.print(“BIRDS PREVENTION”);


pinMode(A0, INPUT);

pinMode(trigPin, OUTPUT);

pinMode(echoPin, INPUT);

pinMode(BUZZER  , OUTPUT);

pinMode(LEVEL, INPUT);

pinMode( LLEVEL, INPUT);

digitalWrite(LLEVEL, HIGH);

digitalWrite(LEVEL, HIGH);

pinMode(   DRAIN, OUTPUT);

digitalWrite(DRAIN, LOW);


digitalWrite(MOTOR, LOW);


void loop()



digitalWrite(trigPin, LOW);


digitalWrite(trigPin, HIGH);


digitalWrite(trigPin, LOW);

length = pulseIn(echoPin, HIGH);

distance = duration/58.2;

if ((distance &gt;= maximumRange )|| (distance &lt;= minimumRange))






















  1. www.signal.uu.se/Research/PCCwirelessIP.html.
  2. https://en.wikipedia.org/wiki/Soil_moisture_sensor
  3. http://www.dummies.com/computers/arduino/how-to-spin-a-dc-motor-with-a-arduino/
  4. https://www.arduino.cc/en/Tutorial/ArduinoToBreadboard
  5. https://arduino-info.wikispaces.com/Capacitors
  6. www.datasheetcatalog.com
  7. A BJT Transistor Aory – a textbook by PCB Heaven.
  8. Seguier, G., Power Electronic Converters – AC/DC Conversion, McGraw-Hill, 1986.



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