15EI305L-DESIGN PROJECT LAB MANUAL

15EI305L-DESIGN PROJECT LAB MANUAL Department of Electronics and Instrumentation Engineering Faculty of Engineering and Technology Department of Electronics and Instrumentation Engineering SRM Institute of Science & Technology, SRM Nagar Kattankulathur 603203 Kancheepuram District Tamil Nadu 1

CONTENTS S.No. CONTENTS Page No. 1 Mark Assessment details 3 2 General Instructions for Laboratory classes 4 3 Syllabus 5 4 List of Experiments 4.1 Design of regulated power supply 7 4.2 Instrumentation amplifier 12 4.3 Design of filters: LPF,HPF,BPF and BRF 16 4.4 I to V and V to I convertor 23 4.5 Design of RC phase shift oscillator 28 4.6 Design of digital clock 34 4.7 Speed control of motor 40 4.8 Automatic water level control 45 4.9 Automatic head light control 50 4.10 Home automation 55 2

1. MARK ASSESSMENT DETAILS ALLOTMENT OF MARKS: Internal assessment = 60 marks Practical examination = 40 marks ---------------------- Total = 100 marks ---------------------- INTERNAL ASSESSMENT (60 MARKS) Split up of internal marks Record Model exam Quiz/Viva Experiments Total 5 marks 10 marks 5 marks 40 marks 60 marks PRACTICAL EXAMINATION (40 MARKS) Split up of practical examination marks Aim and Procedure Circuit Diagram Tabulation Result Viva voce Total 25 marks 30 marks 30 marks 05 marks 10 marks 100 marks 3

2. GENERAL INSTRUCTIONS FOR LABORATORY CLASSES 1. Enter the Lab with CLOSED TOE SHOES. 2. Students should wear lab coat. 3. The HAIR should be protected, let it not be loose. 4. TOOLS, APPARATUS and COMPONENT sets are to be returned before leaving the lab. 5. HEADINGS and DETAILS should be neatly written i. Aim of the experiment ii. iii. iv. Apparatus required Theory Procedure v. Design calculations vi. vii. viii. Circuit diagram Tabulations/ Waveforms Result 6. Experiment number and date should be written in the appropriate place. 7. After completing the experiment, the answer to pre lab viva-voce questions should be neatly written in the workbook. 8. Be REGULAR, SYSTEMATIC, PATIENT, AND STEADY. 4

15EI305L 3. SYLLABUS Design project Laboratory L T P C 0 0 2 1 Co-requisite: Prerequisite: Data Book / Codes/Standards NIL 15EI205,15EI203J NIL Course Category P PROFESSIONAL CORE ELECTRONICS ENGINEERING Course designed by Department of Electronics and Instrumentation Engineering Approval 32 nd Academic Council Meeting held on 23 rd July, 2016 PURPOSE To develop skills in designing and conducting experiments related to applications of principles of physics in engineering. INSTRUCTIONAL OBJECTIVES STUDENT OUTCOMES At the end of the course, student will be able to 1. Develop their ability in designing of basic electronic circuits a b c k 2. Familiarize with the concepts of automation and its concepts a b c d k Sl.No. Description of Experiments Conduct hours C- D-I- O IOs Reference 1 Design of regulated power supply 2 D,I 1 1,2 2 Instrumentation amplifier 2 C,D 1 1,2 3 Design of filters: LPF,HPF,BPF and BRF 4 D 1 1,2 4 I to V and V to I convertor 2 D 1 1,2 5 6 Design of oscillator Design of digital clock 2 D 1 1,2 3 D,I 1,2 1 5

Sl.No. Description of Experiments Conduct hours C- D-I- O IOs Reference 7 8 9 10 Speed control of motor Automatic water level control Automatic head light control Home automation Total contact hours 3 D,I 1,2 1 3 D,I 1,2 1 3 D,I 1,2 1 6 D,I 1,2 1 30 LEARNING RESOURCES Sl. No. REFERENCE BOOKS 1. Laboratory Manual 2. Roy choudhury and shailjain linear integrated circuits, 4 th edition, New Age, 2011 Course nature Practical Assessment Method (Weightage 100%) Insemester Assessment tool Experiments Record MCQ/Quiz/Viva Voce Model examination Total Weightage 40% 5% 5% 10% 60% Weightage : 40% End semester examination STUDENT OUTCOMES: a,c. An ability to design and conduct experiments on amplifiers, oscillators & filters. e,d. An ability to use the techniques, skills and modern engineering tools of electronic circuits for project design. 6

DATE: EXPERIMENT NO-1 DESIGN OF REGULATED POWER SUPPLY OBJECTIVE (AIM) OF THE EXPERIMENT: To design a regulated power supply circuit to generate output voltage +5V and -5V. APPARATUS REQUIRED: S.NO APPARATUS SPECIFIACTIONS QUANTITY 1. Transformer 230V/9-0-9 1 2. Diodes 1N4001 4 3. Capacitors 470µF 4 4. Regulators IC7805 IC7905 1 1 5. DSO - 1 6. Breadboard - 1 THEORY: A regulated power supply is an embedded circuit; it converts unregulated AC into a constant DC. With the help of a rectifier it converts AC supply into DC. Its function is to supply a stable voltage (or less often current), to a circuit or device that must be operated within certain power supply limits. The output from the regulated power supply may be alternating or unidirectional, but is nearly always DC. The type of stabilization used may be restricted to ensuring that the output remains within certain limits under various load conditions, or it may also include compensation for variations in its own supply source. The latter is much more common today. D.C. variable bench supply (a bench power supply usually refers to a power supply capable of supplying a variety of output voltages useful for BE bench testing electronic circuits, possibly with continuous variation of the output voltage, or just some preset voltages; a laboratory (lab) power supply normally implies an accurate bench power supply, while a balanced or tracking power supply refers to twin supplies for use when a circuit requires both positive and negative supply rails). PROCEDURE: Connect the circuit as shown in figure. Connect the probes to DSO & Switch ON Check the graph for both positive and negative voltage and note down the Output voltage. 7

DESIGN PROCEDURE/DESIGN CALCULATIONS: Vin = 230V Vmax= Rms secondary voltage 2 Vmax = 15 2 = 21.21V Vout = Vmin - 20.7 Vripple = 10.69V Vout = 21.21 X 0.9 = 19.09V C= 8 X 10-3 X 0.5 / 10.69 = 0.3748 X 10-3 = 374 Therefore 470µF can be used. 8

CIRCUIT DIAGRAM: MODEL GRAPH: Secondary Voltage of the transformer Rectified Waveform 9

Filtered Regulated Output TABULATION: SECONDARY VOLTAGE(V) RECTIFIED OUTPUT(V) REGULATED OUTPUT(V) 10

RESULT: Thus the RPS circuit has been successfully designed and the desired output waveform was thus verified and obtained. 11

DATE: EXPERIMENT: 2 DESIGN OF INSTRUMENTATION AMPLIFIER OBJECTIVE (AIM) OF THE EXPERIMENT : To design an instrumentation amplifier with a gain of 3. APPRATUS REQUIRED: SERIAL NUMBER APPARATUS RANGE QUANTITY 1. RESISTORS 1K, 2K, 4K 4,2,1 2. OP-AMP IC 741 3 3. RPS (0-30)V 1 4. DSO - 1 5. LINEAR POWER +15V 0 15V 1 SUPPLY 6. WIRES - FEW THEORY : An instrumentation (or instrumentational) amplifier is a type of differential amplifier that has been outfitted with input buffer amplifiers, which eliminate the need for input impedance matching and thus make the amplifier particularly suitable for use in measurement and test equipment. Additional characteristics include very low DCoffset, low drift, low noise, very high open-loop gain, very high common-mode rejection ratio, and very high input impedances. Instrumentation amplifiers are used where great accuracy and stability of the circuit both short and long-term are required. Although the instrumentation amplifier is usually shown schematically identical to a standard operational amplifier (op-amp), the electronic instrumentation amp is almost always internally composed of 3 op-amps. These are arranged so that there is one op-amp to buffer each input (+, ), and one to produce the desired output with adequate impedance matching for the function. PROCEDURE: 1. Connect the circuit as shown in the figure 2. Connect the power supply V1 and V2 down the output voltage. 12

DESIGN PROCEDURE/DESIGN CALCULATIONS: For gain of 3 R2=2KΩ, R1=1KΩ, R =1KΩ, R=4KΩ Gain= (R2/R1) (1+2R /R) =2[1+0.5] GAIN = 3 We know that the output voltage V in instrumentation amplifier is given by Vout = (V1 V2) (R2/R1) (1+2R /R) CIRCUIT DIAGRAM: MODEL GRAPH : V2 13

V1 OUTPUT VOLTAGE TABULATION : S.NO V1(V) V2(V) Vout(V) GAIN 1. 2. 14

RESULT : Thus the design of instrumentation amplifier was successfully done and required output voltage for gain 3 is obtained. 15

DATE: EXPERIMENT NO 3 DESIGN OF LPF, HPF, BPF, BRF OBJECTIVE (AIM) OF THE EXPERIMENT: To design the various active filters circuits low pass filter,high pass filter,band pass filter,band reject filter. APPARATUS REQUIRED: S.NO APPARATUS SPECIFICATION QUANTITY 1 SIGNAL (0-10)mHz 1 GENERATOR 2 Op amp IC741 3 3 Resistors 1kΩ,1.5kΩ 2,1,2,4 5kΩ,10kΩ 4 Capacitor 0.1μf 4 5 linear power supply ±15V 1 6 DSO - 1 THEORY: Electronic filters are circuits which perform signal processing functions, specifically to remove unwanted frequency components from the signal, to enhance wanted ones, or both. Electronic filter high-pass, low-pass, band-pass, band-stop (band-rejection; notch), or allpass. Active Low Pass Filter: The most common and easily understood active filter is the Active Low Pass Filter. Its principle of operation and frequency response is exactly the same as those for the previously seen passive filter, the only difference this time is that it uses an op-amp for amplification and gain control. The simplest form of a low pass active filter is to connect an inverting or non-inverting amplifier. High Pass Filter : A first-order (single-pole) Active High Pass Filter as its name implies, attenuates low frequencies and passes high frequency signals. It consists simply of a passive filter section followed by a non-inverting operational amplifier. The frequency response of the circuit is the same as that of the passive filter, except that the amplitude of the signal is increased by the gain of the amplifier and for a non-inverting amplifier the value of the pass band voltage gain is given as 1 + R2/R1, the same as for the low pass filter circuit. Band Pass Filter: The cut-off frequency or ƒc point in a simple RC passive filter can be accurately controlled using just a single resistor in series with a non-polarized capacitor, and depending upon which way around they are connected, we have seen that either a Low Pass or a High Pass filter is obtained.by connecting or cascading together a single Low Pass Filter circuit with a High Pass Filter circuit, we can produce another type of passive RC filter that passes a selected range or band of frequencies that can be either narrow or wide while attenuating all those outside of this range. This new type of passive filter arrangement produces a 16

frequency selective filter known commonly as a Band Pass Filter or BPF for short. Unlike a low pass filter that only pass signals of a low frequency range or a high pass filter which pass signals of a higher frequency range, a Band Pass Filters passes signals within a certain band or spread of frequencies without distorting the input signal or introducing extra noise. This band of frequencies can be any width and is commonly known as the filters Bandwidth. Band reject Filter: The Band Stop Filter, (BSF) is another type of frequency selective circuit that functions in exactly the opposite way to the Band Pass Filter we looked at before. The band stop filter, also known as a band reject filter, passes all frequencies with the exception of those within a specified stop band which are greatly attenuated. If this stop band is very narrow and highly attenuated over a few hertz, then the band stop filter is more commonly referred to as a notch filter, as its frequency response shows that of a deep notch with high selectivity (a steep-side curve) rather than a flattened wider band. The function of a band stop filter is too pass all those frequencies from zero (DC) up to its first (lower) cut-off frequency point ƒl, and pass all those frequencies above its second (upper) cut-off frequency ƒh, but block or reject all those frequencies in-between. Then the filters bandwidth, BW is defined as: (ƒh ƒl). Procedure: 1)Connect the circuit as shown in diagram. 2)Connect the DSO to the probes and switch it on. 3)Check the graph for both positive and negative voltage and write down the outut. DESIGN CALCULATION: GAIN = (1 + Rf Ri ) 17

CIRCUIT DIAGRAM: LOW PASS FILTER: HIGH PASS FILTER: BAND PASS FILTER 18

Band Reject filter: MODEL GRAPH: Band reject filter: 19

Band pass filter: low pass filter: High pass filter: 20

TABULATION: LPF: INPUT FREQUENCY(HZ) OUTPUT VOLTAGE(V) GAIN GAIN IN db HPF: INPUT FREQUENCY(HZ) OUTPUT VOLTAGE(V) GAIN GAIN IN db BPF: INPUT FREQUENCY(HZ) OUTPUT VOLTAGE(V) GAIN GAIN IN db BRF: INPUT FREQUENCY(HZ) OUTPUT VOLTAGE(V) GAIN GAIN IN db 21

RESULT: Thus the various active filter circuits, low pass, high pass, band pass was designed and the frequency response was analyzed. 22

DATE: EXPERIMENT NO-4 DESIGN OF V-I AND I V CONVERTER AIM: To design V-I and I-V Converter APPARATUS REQUIRED: S.NO APPARATUS SPECIFIACTIONS QUANTITY 1. Resistor 220KΩ,1KΩ,10 KΩ 1 2. OP-AMP IC741 1 3. Breadboard - 1 4. RPS (0-30)V 1 5. Voltmeter (0-30)V 1 6. Current source (0-100)mA 1 7. Linear power supply ±15V 1 8. Connecting wires - As required THEORY: A regulated power supply is an embedded circuit; it converts unregulated AC into a constant DC. With the help of a rectifier it converts AC supply into DC. Its function is to supply a stable voltage (or less often current), to a circuit or device that must be operated within certain power supply limits. The output from the regulated power supply may be alternating or unidirectional, but is nearly always DC. The type of stabilization used may be restricted to ensuring that the output remains within certain limits under various load conditions, or it may also include compensation for variations in its own supply source. The latter is much more common today. D.C. variable bench supply (a bench power supply usually refers to a power supply capable of supplying a variety of output voltages useful for BE bench testing electronic circuits, possibly with continuous variation of the output voltage, or just some preset voltages; a laboratory (lab) power supply normally implies an accurate bench power supply, while a balanced or tracking power supply refers to twin supplies for use when a circuit requires both positive and negative supply rails). PROCEDURE: Connect the circuit as shown in figure. Measure the circuit output. Tabulate reading. 23

CIRCUIT DIAGRAM: a) V-I Converter b)i-v CONVERTER 24

MODEL GRAPH: V-I Converter I-V Converter TABULATION: a)v-i CONVERTER 25

S.NO INPUT VOLTAGE(V) OUTPUT CURRENT(mA) b) I=V CONVERTER S.NO INPUT CURRENT(mA) OUTPUT VOLTAGE(V) 26

RESULT: Thus the design of V-I and I-V Converters are successfully done and the output characteristics are plotted and thus verified. 27

DATE: EXPERIMENT NO-5 DESIGN OF RC PHASE SHIFT OSCILLATOR OBJECTIVE (AIM) OF THE EXPERIMENT To design and construct a RC phase shift oscillator for the given frequency. APPARATUS REQUIRED: S.NO APPARATUS RANGE QUANTITY 1. Power supply (0-30)V 1 2. Function generator (0-20M)Hz 1 3. CRO 1 4. Transistor BC107 1 5. Resistors 6. 7. Capacitors Connecting wires THEORY: In the RC phase shift oscillator, the required phase shift of 180 in the feedback loop from the output to input is obtained by using R and C components, instead of tank circuit. Here a common emitter amplifier is used in forward path followed by three sections of RC phase network in the reverse path with the output of the last section being returned to the input of the amplifier. The phase shift Ф is given by each RC section Ф=tanˉ1 (1/ωrc). In practice R-value is adjusted such that Ф becomes 60. If the value of R and C are chosen such that the given frequency for the phase shift of each RC section is 60. Therefore at a specific 28

frequency the total phase shift from base to transistor s around circuit and back to base is exactly 360 or 0. Thus the Barkhausen criterion for oscillation is satisfied CIRCUIT DIAGRAM: DESIGN PROCEDURE: V cc = 12V I c = 1mA; A v = 30; R f = 2.5KΩ; s = 2; f=1khz; r e = 26mV I c = β = 1 R f = 29

h fe = h ie = h fe r e ; V ce = V cc 2 V E = V CC 10 ; Applying KVL to output loop, we get V cc = I E R E + I C R C + V ce ; R C = Since I B is very small when compare with I C, I C I E R E = V E I E ; S = 1 + R B R E R B = V B = V CCR 2 (R 1 + R 2 ) R B = R 1 //R 2 R 1 = R 2 = Gain formula is given by A v = h fe R Leff h ie A v = 29; R Leff = R C //R L ; R L = X Ci = ([h ie + 1 + h fe R E ]//R B )/10 = C i = 1/2πfX Ci X CO = RL eff 10 ; C o = 1/2πfX CO 30

C E = R E 10 ; C E = 1/2πfX CE C=0.01µF; f = 1/2πRC 6 R= TABULAR COLOUMN: Amplitude Time Frequency MODEL GRAPH: PROCEDURE: 1. Connections are made as per the circuit diagram. 2. Switch on the power supply and observe the output on the CRO (sine wave). 3. Note down the practical frequency and compare with its theoretical frequency. 31

RESULT: Thus RC phase shift oscillator is designed and constructed and the output sine wave frequency is calculated as Frequency Theoretical Practical 32

Prelab Questions: 1) What is oscillator circuit? 2) What are the different types of oscillators? 3) What are the conditions for oscillations? 4) Define frequency loop? Postlab Questions: 1) What are the applications of RC phase shift oscillator? 2) Why RC oscillator cannot generate high frequency oscillations? 3) What phase shift does RC phase oscillator produce? 4) How is phase angle determined in RC phase shift oscillator? 5) How can we get a maximum phase angle of 90 0 in RC phase shift oscillator 33

DATE: EXPERIMENT NO-6 DESIGN OF DIGITAL CLOCK OBJECTIVE (AIM) OF THE EXPERIMENT To design a Digital clock and to observe its output. APPARATUS REQUIRED S.NO APPARATUS SPECIFICATION QUANTITY 1. IC 555 timer 1 2. Resistors 10KΩ, 220Ω 1each 100KΩ(VARIABLE) 1 3. Capacitors 10uf, 0.1µF, 10nf 1each 4. Battery ±9V 1 6. Diode 1N4148 3 7. MOD COUNTER 74LS90 6 8. BCD TO 7SEGMENT 74LS47 6 9. AND GATE 7408 1 10. Connecting wires - Req. THEORY: Digital clocks typically use the 50 or 60 hertz oscillation of AC power or a 32,768 hertz crystal oscillator as in a quartz clock to keep time. Most digital clocks display the hour of the day in 24-hour format; in the United States and a few other countries, a more commonly used hour sequence option is 12-hour format (with some indication of AM or PM). Some timepieces, such as many digital watches, can be switched between 12-hour and 24-hour modes. Emulations of analog-style faces often use an LCD screen, and these are also sometimes described as digital. If people find difficulty in setting the time in some designs of digital clocks in electronic devices where the clock is not a critical function, they may not be set at all, displaying the default after powered on, 00:00 or 12:00.Digital clocks that run on mains electricity and have no battery must be reset every time the power is cut off or if they are moved. Even if power is cut off for a second, most clocks will still have to be reset. This is a 34

particular problem with alarm clocks that have no battery backup, because even a very brief power outage during the night usually results in the clock failing to trigger the alarm in the morning PROCEDURE: Hook up the circuit as shown in the circuit diagram. Switch on the power supply. Observe the maximum clock initially. Use MOD 10, 6, 3counters to count. After counting to display count values are given for BCD to 7ssegment conerter. Thus the clock vales are displayed. 35

CIRCUIT DIAGRAM CLOCK GENERATOR ONE SEGMENT DISPLAY 36

COMPLETE 37

RESULT: Thus the design of digital clock was successfully done and the required digital timings are obtained. The output was thus verified and obtained. 38

Prelab Questions: 5) What is the difference between digital and analog clock? 6) How many segments needed to measure hh:mm:ss? 7) What is common anode and common cathode? Postlab Questions: 6) What are the applications of digital clock? 7) How many counters of mod 6 and mod 10 needed? 8) What is the clock frequency for mod counters? 9) Define working of complete circuit? 39

DATE: EXPERIMENT NO-7 SPEED CONTROL OF MOTOR OBJECTIVE (AIM) OF THE EXPERIMENT To design a speed control of motor and to observe its output. APPARATUS REQUIRED S.NO APPARATUS SPECIFICATION QUANTITY 1. IC 741 2 2. Resistors 10KΩ(VARIABLE) 1 3. CRO - 1 4. RPS 12V 1 7. Motor 12V DC 1 8. Connecting wires - Req. THEORY: Today s industries are increasingly demanding process automation in all sectors. Automation results into better quality, increased production an reduced costs. The variable speed drives, which can control the speed of A.C/D.C motors, are indispensable controlling elements in automation systems. Depending on the applications, some of them are fixed speed and some of the variable speed drives. The variable speed drives, till a couple of decades back, had various limitations, such as poor efficiencies, larger space, lower speeds, etc., However, the advent power electronic devices such as power MOSFETs, IGBTs etc., and also with the introduction of micro - controllers with many features on the same silicon wafer, transformed the scene completely and today we have variable speed drive systems which are not only in the smaller in size but also very efficient, highly reliable and meeting all the stringent demands of various industries of modern era. 40

PROCEDURE: Hook up the circuit as shown in the circuit diagram. Switch on the power supply. Observe the maximum RPM initially. Thus the speed of the motor can be controlled by varying VR1. 41

CIRCUIT DIAGRAM 42

RESULT: Thus the design of speed control of motor was successfully done and the required control is obtained. The output was thus verified and obtained. 43

Prelab Questions: 8) What is speed control? 9) What are the different types of motors? 10) What is PWM? 11) Define variable resistor? Postlab Questions: 10) What are the applications of speed control? 11) How DC motor operates? 12) Explain IC 741? 44

DATE: EXPERIMENT NO-8 AUTOMATIC WATER LEVEL CONTROL OBJECTIVE (AIM) OF THE EXPERIMENT To design a Automatic water level control and to observe its output. APPARATUS REQUIRED S.NO APPARATUS SPECIFICATION QUANTITY 1. IC IC555 1 2. Resistors 10KΩ,1M, 3,2,1 100KΩ 3. Capacitors 0.01µF 1 4. RPS ±12V 1 5 Transistor BC547 1 6. Diode 1N4007 1 7. Relay DC 12V 1 8. Motor DC 12V 1 6. Connecting wires - Req. THEORY: Level sensors detect the level of liquids and other fluids and fluidized solids, including slurries, granular materials, and powders that exhibit an upper free surface. Substances that flow become essentially horizontal in their containers (or other physical boundaries) because of gravity whereas most bulk solids pile at an angle of repose to a peak. The substance to be measured can be inside a container or can be in its natural form (e.g., a river or a lake). The level measurement can be either continuous or point values. Continuous level sensors measure level within a specified range and determine the exact amount of substance in a certain place, while point-level sensors only indicate whether the substance is above or below the sensing point. Generally the latter detect levels that are excessively high or low. 45

PROCEDURE: Hook up the circuit as shown in the circuit diagram. Switch on the power supply. Observe the water level initially. Then motor starts pumping the water when the water level is below low level and fills the water tank. When the water level reaches H motor automatically stops. 46

CIRCUIT DIAGRAM 47

RESULT: Thus the design of Water level control was successfully done and the required level control is obtained. The output was thus verified and obtained. 48

Prelab Questions: 12) What is level control? 13) What are the sensors used for level measurement? Postlab Questions: 13) How 555 timer generates clock cycles? 14) What is the cut off voltage of BC547? 15) How relay switches from NC to NO? 49

DATE: EXPERIMENT NO-9 AUTOMATIC HEAD LIGHT CONTROL OBJECTIVE (AIM) OF THE EXPERIMENT To design an automatic head light low/high beam control and to observe its hardware output. APPARATUS REQUIRED S.NO APPARATUS SPECIFICATION QUANTITY 1. Transistor BC547 1 2. Resistors 10KΩ,1KΩ. Each1 3. Diode 1N4007 1 4. LDR - 1 5. RPS ±12V 1 6. Relay 12V 1 7. Connecting wires - Req. THEORY: The requirement of headlight is very common during night travel. The same headlight which assists the driver for better vision during night travel is also responsible for many accidents that are being caused. The driver has the control of the headlight which can be switched from high beam (bright) to low beam (dim). The headlight has to be adjusted according to the light requirement by the driver. During pitch black conditions where there are no other sources of light, high beam is used to. On all other cases, low beam is preferred. But in a two-way traffic, there are vehicles plying on both sides of the road. So when the bright light from the headlight of a vehicle coming from the opposite direction falls on a person, it glares him for a certain amount of time. This causes disorientation to that driver. This discomfort will result in involuntary closing of the driver s eyes momentarily. This fraction of distraction is the prime cause of many road accidents. The prototype that is has been designed, reduces this problem by actually dimming down the bright headlight of our vehicle to low beam automatically when it senses a vehicle at close proximity approaching 50

from the other direction. The entire working of the dimmer is a simple electronic circuitry arrangement which senses and switches the headlight according to the conditions required. PROCEDURE: Hook up the circuit as shown in the circuit diagram. Switch on the power supply. Observe the high beam output due to no vehicle. Observe the low beam output at arrival of vehicle. 51

CIRCUIT DIAGRAM R1 = 1K, P1 = 10 K, 52

RESULT: Thus the Automatic Head light low/high beam control was successfully done and the required output is obtained. The high and low beam output was thus verified and obtained. 53

Prelab Questions: 14) What is headlight control? 15) What are the sensors for headlight control? Postlab Questions: 16) How LDR works? 17) What is the purpose of transistor in our circuit? 54

DATE: EXPERIMENT NO-10 HOME AUTOMATION OBJECTIVE (AIM) OF THE EXPERIMENT: To design and construct a Home automation circuit using DTMF decoder. APPARATUS REQUIRED: S.NO APPARATUS RANGE QUANTIT Y 1. Power supply (0-30)V 1 2. GSM module SIM 800 1 3. DTMF decoder MT8870 1 4. Transistor BC107 1 5. Resistors 100K, 330 K 2,1 6. Capacitors 10uf, 0.1uf 1,1 7. Relay and bulb DC 12V and zero watt 1,1 THEORY: Home automation gives you access to control devices in your home from a mobile device anywhere in the world. The term may be used for isolated programmable devices, like thermostats and sprinkler systems, but home automation more accurately describes homes in which nearly everything -- lights, appliances, electrical outlets, heating and cooling systems - - are hooked up to a remotely controllable network. From a home security perspective, this also includes your alarm system, and all of the doors, windows, locks, smoke detectors, surveillance cameras and any other sensors that are linked to it. 55

Until fairly recently, automated central control of building-wide systems was found only in larger commercial buildings and expensive homes. Typically involving only lighting, heating and cooling systems, building automation rarely provided more than basic control, monitoring and scheduling functions and was accessible only from specific control points within the building itself. PROCEDURE: 1. Connections are made as per the circuit diagram. 2. Switch on the power supply and observe the output. 3. Call from transmitter mobile to the number in the receiver. 4. By pressing each number in the transmitter particular tone is received in 8870 decoder. 5. Finally using transistor and relay bulb can be controlled. 56

CIRCUIT DIAGRAM: 57

RESULT: Thus home automation is designed and constructed and the output is verified. 58

Prelab Questions: 1) What is automation? 2) What is automation in home? 3) What is DTMF? 4) Define Relay control? Postlab Questions: 1) For which purpose relay used? How? 2) What is the cut off voltage of transistor? 3) What phase shift does RC phase oscillator produce? 4) What is the use of DTMF? 59