Synopsis sample

Rizvi College of Engineering

Synopsis report on Electronic Workshop

Student Name

PRINCIPAL

HOD (EXTC)

Dr .Varsha Shah Prof. Rajan S. Deshmukh

In-charge

Coordinator

Title:

RF BASED WIRELESS REMOTE CONTROL

AIM:

RF BASED WIRELESS REMOTE CONTROL

ABSTRACT:

modules are used to transmit and receive digital code. It has carrier frequency of 433.92 MHz and operating range of around 100-150 mts.

CIRCUIT DIAGRAM:

COMPONENTS:

a)

d) L.E.D,

f) Battery.

COMPONENTS DESCRIPTION:

a)

with 212 _{series of decoders for use in remote control system applications. It is mainly used in}

interfacing RF and infrared circuits. The chosen pair of encoder/decoder should have same number of addresses and data format.

Simply put, HT12E converts the parallel inputs into serial output. It encodes the 12 bit parallel data into serial for transmission through an RF transmitter. These 12 bits are divided into 8 address bits and 4 data bits.

HT12E has a transmission enable pin which is active low. When a trigger signal is received on TE pin, the programmed addresses/data are transmitted together with the header bits via an RF or an infrared transmission medium. HT12E begins a 4-word transmission cycle upon receipt of a transmission enable. This cycle is repeated as long as TE is kept low. As soon as TE returns to high, the encoder output completes its final cycle and then stops.

Pin Diagram:

Pin Description: Pin

No Function Name

1 8 bit Address pins for input A0

2 A1

3 A2

5 A4

6 A5

7 A6

8 A7

9 Ground (0V) Ground

10

4 bit Data/Address pins for input

AD0

11 AD1

12 AD2

13 AD3

14 Transmission enable; active low TE

15 Oscillator input Osc2

16 Oscillator output Osc1

17 Serial data output Output

18 Supply voltage; 5V (2.4V-12V) Vcc

b) HT12D: It is a decoder integrated circuit that belongs to 212 _{series of decoders.}

This series of decoders are mainly used for remote control system applications, like burglar alarm, car door controller, security system etc. It is mainly provided to interface RF and

infrared circuits. They are paired with 212 _{series of encoders. The chosen pair of}

encoder/decoder should have same number of addresses and data format.

In simple terms, HT12D converts the serial input into parallel outputs. It decodes the serial addresses and data received by, say, an RF receiver, into parallel data and sends them to output data pins. The serial input data is compared with the local addresses three times continuously. The input data code is decoded when no error or unmatched codes are found. A valid transmission in indicated by a high signal at VT pin.

HT12D is capable of decoding 12 bits, of which 8 are address bits and 4 are data bits. The data on 4 bit latch type output pins remain unchanged until new is received.

Pin Description: Pin

No

Function Name

1

8 bit Address pins for input

A0 2 A1 3 A2 4 A3 5 A4 6 A5 7 A6 8 A7

9 Ground (0V) Ground

10

4 bit Data/Address pins for output

D0

11 D1

12 D2

13 D3

14 Serial data input Input

15 Oscillator output Osc2

16 Oscillator input Osc1

17 Valid transmission; active high VT

18 Supply voltage; 5V (2.4V-12V) Vcc

c) RF module: As the name suggests, operates at Radio Frequency. The

corresponding frequency range varies between 30 kHz & 300 GHz. In this RF system, the digital data is represented as variations in the amplitude of carrier wave. This kind of modulation is known as Amplitude Shift Keying (ASK).Transmission through RF is better than IR (infrared) because of many reasons. Firstly, signals through RF can travel through larger distances making it suitable for long range applications. Also, while IR mostly operates in line-of-sight mode, RF signals can travel even when there is an obstruction between transmitter & receiver. Next, RF transmission is more strong and reliable than IR transmission. RF communication uses a specific frequency unlike IR signals which are

affected by other IR emitting sources .This RF module comprises of an RF Transmitter and

an RF Receiver. The transmitter/receiver (Tx/Rx) pair operates at a frequency of 434 MHz. An RF transmitter receives serial data and transmits it wirelessly through RF through its antenna connected at pin4. The transmission occurs at the rate of 1Kbps - 10Kbps.The transmitted data is received by an RF receiver operating at the same frequency as that of the transmitter. The RF module is often used along with a pair of encoder/decoder. The encoder is used for encoding parallel data for transmission feed while reception is decoded by a decoder. HT12E-HT12D, HT640-HT648, etc. are some commonly used encoder/decoder pair ICs.

Pin Description:

RF Transmitter Pin

No Function Name

1 Ground (0V) Ground

2 Serial data input pin Data

3 Supply voltage; 5V Vcc

4 Antenna output pin ANT

RF Receiver Pin

No Function Name

1 Ground (0V) Ground

2 Serial data output pin Data

3 Linear output pin; not connected NC

4 Supply voltage; 5V Vcc

5 Supply voltage; 5V Vcc

6 Ground (0V) Ground

7 Ground (0V) Ground

8 Antenna input pin ANT

d) L.E.D: A diode is a component that only allows electricity to flow one way. It can be thought as a sort of one way street for electrons. Because of this characteristic, diodes are used to transform or rectify AC voltage into a DC voltage. Diodes have two connections, an anode and a cathode. The cathode is the end on the schematic with the point of the triangle pointing towards a line. In other words, the triangle points toward that cathode.

e)PCB (Printed Circuit Board): With the help of P.C.B it is easy to assemble circuit with neat and clean end products. P.C.B is made of Bakelite with surface pasted with copper track-layout. For each components leg, hole is made.

Connection pin is passed through the hole and is soldered.

WORKING:

This circuit utilizes the RF module ( Tx/Rx) for making a wireless remote, which could be used to drive an output from a distant place. RF module, as the name suggests, uses radio frequency to send signals. These signals are transmitted at a particular frequency and a baud rate. A receiver can receive these signals only if it is configured for that frequency. This radio frequency (RF) transmission system employs Amplitude Shift Keying (ASK) with transmitter/receiver (Tx/Rx) pair operating at 434 MHz . The transmitter module takes serial input and transmits these signals through RF. The transmitted signals are received by the receiver module placed away from the source of transmission.

The system allows one way communication between two nodes, namely, transmission and reception. The RF module has been used in conjunction with a set of four channel encoder/decoder ICs. Here HT12E & HT12D have been used as encoder and decoder respectively. The encoder converts the parallel inputs (from the remote switches) into serial set of signals. These signals are serially transferred through RF to the reception point. The decoder is used after the RF receiver to decode the serial format and retrieve the original signals as outputs. These outputs can be observed on corresponding LEDs.

parallel signals. The encoder HT12E encodes these parallel signals into serial bits. Transmission is enabled by providing ground to pin14 which is active low. The control signals are given at pins 10-13 of HT12E. The serial data is fed to the RF transmitter through pin17 of HT12E.

CONCLUSION:

The circuit can be used for designing Remote Appliance Control system. The outputs from the receiver can drive corresponding relays connected to any household appliance.

ADVANTAGE :

Special ASK transmitter and receiver modules are used to transmit and receive digital code.

FUTURE MODIFICATIONS:

Title:

AIM: Automatic Street lights

Abstract:

This is project is developed for street lights such that they do not require manual operation for switching ON and OFF

Circuit Diagram:

Components:

a) 9v Battery with strip

b) Switch

c) L.D.R (Light Depending Resistance)

d) I.C NE555 with Base

e) L.E.D (Light Emitting Diode) 3 to 6 pieces.

f) Variable Resistance of 47 Kilo ohms

Components Description:

a) Battery: For 9v power supply we can use 6pcs dry cell or 6F22 9v single piece battery.

b) Switch: Any general purpose switch can be used. Switch is used as circuit breaker.

c) L.D.R: (Light Depending Resistance) it is a special type of resistance whose value depends

on the brightness of light which is falling on it. It has resistance of about 1mega ohm when in total darkness but a resistance of only about 5k ohms when brightness illuminated.

It responds to a large part of light spectrum.

d) L.E.D:A diode is a component that only allows electricity to flow one way. It can be

thought as a sort of one way street for electrons. Because of this characteristic, diodes are used to transform or rectify AC voltage into a DC voltage. Diodes have two connections, an anode and a cathode. The cathode is the end on the schematic with the point of the triangle pointing towards a line. In other words, the triangle points toward that cathode. The anode is, of course, the opposite end. Current flows from the anode to the cathode. Light emitting diodes, or LEDs, differ from regular diodes in that when a voltage is applied, they emit light.

This light can be red (most common), green, yellow, orange, blue (not very common) or infa red. LEDs are used as indicators, transmitters, etc. Most likely, a LED will never burn out like a regular lamp will and requires many times less current. Because LEDs act like regular diodes and will form a short if connected between + and -, a current limiting resistor is used to prevent that very thing. LEDs may or may not be drawn with the circle surrounding them.

e) Variable resistance: Resistors are one of the most common electronic components. A

f) PCB (Printed Circuit Board) :with the help of P.C.B it is easy to assemble circuit with neat and clean end products. P.C.B is made of Bakelite with surface pasted with copper track layout. For each components leg, hole is made. Connection pin is passed through the hole and is soldered.

Working:

pin-6 connected with positive rail, the output goes high(1) when the trigger pin 2 is at lower then 1/3rd level of the supply voltage. Conversely the output goes low (0) when it is above 1/3rd level. So small change in the voltage of pin-2 is enough to change the level of output (pin-3) from 1 to 0 and 0 to 1. The output has only two states high and low and can not remain in any intermediate stage. It is powered by a 6V battery for portable use. The circuit is economic in power consumption. Pin 4, 6 and 8 is connected to the positive supply and pin 1 is grounded. To detect the present of an object we have used LDR and a source of light. LDR is a special type of resistance whose value depends on the brightness of the light which is falling on it. It has resistance of about 1 mega ohm when in total darkness, but a resistance of only about 5k ohms when brightness illuminated. It responds to a large part of light spectrum. We have made a potential divider circuit with LDR and 100K variable resistance connected in series. We know that voltage is directly proportional to conductance so more voltage we will get from this divider when LDR is getting light and low voltage in darkness. This divided voltage

is given to pin 2 of IC 555. Variable resistance is so adjusted that it crosses potential of 1/3rd

in brightness and fall below1/3rd _{in darkness.}

Sensitiveness can be adjusted by this variable resistance. As soon as LDR gets dark the voltage of pin 2 drops1/3rd of the supply voltage and pin 3 gets high and LED or buzzer which is connected to the output gets activated.

When light falls on the LDR then its resistance decreases which results in increase of the voltage at pin 2 of the IC 555. IC 555 has got comparator inbuilt, which compares between the input voltage from pin2 and 1/3rd of the power supply voltage. When input falls below 1/3rdthenoutputissethighotherwiseitissetlow.Since in brightness input voltage rises so we obtain no positive voltage at output of pin 3 to drive relay or LED, besides in poor light condition we get output to energize.

Precautions:

a) LDR used should be sensitive.

Before using in the circuit it should be tested with multimeter.

b) I.C should not be heated too much while soldering can destroy the I.C. For safety and

easy to replace, use of I.C base is suggested. While placing the I.C pin no 1 should be made sure at right hole.

c) Opposite polarity of battery can destroy I.C so please check the polarity before switching

d) L.E.D glows in forward bias only so incorrect polarity of L.E.D will not glow. Output voltage of our project is 7.3 volt therefore 4 LED in series can be easily used without resistance.

e) Each component should be soldered neat and clean. We should check for any dry soldered.

f) LDR should be so adjusted that it should not get light from streetlight itself.

Conclusion

When there is need of light, circuit detects itself weather there is need for light or not. When darkness rises to a certain value then automatically street light is switched ON and when there is other source of light i.e. day time, the street light gets OFF.

Advantage:

It minimizes use of manual switching of Street Light.

Future modification:

Title:

3 BITS BINARY DOWN COUNTER

ABSTRACT:

In a sense, this circuit ”cheats” by using only two J-K flip-flops to make a three-bit binary counter. Ordinarily, three flip-flops would be used – one for each binary bit – but in this case we can use the clock pulse (555 timer output) as a bit of its own.

CIRCUIT DIAGRAM:

COMPONENTS:

• 555 timer IC (Radio Shack catalog # 276-1723)

• One 1N914 “switching” diode (Radio Shack catalog # 276-1122) • Two 10 k resistors

• One 100 μF capacitor (Radio Shack catalog # 272-1028) • 4027 dual J-K flip-flop (Radio Shack catalog # 900-4394) • Ten-segment bar graph LED (Radio Shack catalog # 276-081) • Three 470 resistors

• One 6 volt battery

WORKING:

When you build this circuit, you will find that it is a “down” counter. That is, its count sequence goes from 111 to 110 to101 to 100 to 011 to 010 to 001 to 000 and then back to 111. While it is possible to construct an “up” counter using J-K flip-flops, this would require additional components and introduce more complexity into the circuit.

It is highly recommended, in this experiment as in all experiments, to build the circuit in Stages identify portions of the circuit with specific functions, and build those portions one at a time, testing each one and verifying its performance before building the next. A very common mistake of new electronics students is to build an entire circuit at once without testing sections of it during the construction process, and then be faced with the possibility of several problems simultaneously when it comes time to finally apply power to it. Remember that a small amount of extra attention paid to detail near the beginning of a project is worth an enormous amount of troubleshooting work near the end! Students who make the mistake of not testing circuit portions before attempting to operate the entire circuit often (falsely) think

that the time it would take to test those sections is not worth it, and then spend days trying to

figure out what the problem(s) might be with their experiment.

Following this philosophy, build the 555 timer circuit first, before even plugging the 4027 IC into the breadboard. Connect the 555’s output (pin #3) to the “Least Significant Bit” (LSB) LED, so that you have visual indication of its status. Make sure that the output oscillates in a slow, square-wave pattern (LED is “lit” for about as long as it is ”off ” in a cycle), and that it is a reliable signal (no erratic behavior, no unexplained pauses). If the 555 timer is not working properly, neither will the rest of the counter circuit! Once the timer circuit has been proven good, proceed to plug the 4027 IC into the breadboard and complete the rest of the necessary connections between it, the 555 timer circuit, and the LED assembly.

ADVANTAGE:

The output of IC 555 is used as 1 bit , saving one J-K flip flop.

DISADVANTAGE:

It cannot be used in up-count mode.

CONCLUSION:

In this the 555 timer operates as a slow, square-wave oscillator with a duty cycle of approximately 50 percent. This duty cycle is made possible by the use of a diode to ”bypass” the lower resistor during the capacitor’s charging cycle, so that the charging time constant is only RC and not 2RC as it would be without the diode in place.

FUTURE MODIFICATIONS:

Title:

AIM: LED VOLTMETER

Abstract:

This is very simple voltage indicator using very less components.

Circuit Diagram:

Components:



IC1-IC4=µA741,



Resistors (1k) ,



LED,

Working:

Here four µ741 op-amps are used here to measure the voltage ranging from 3V to 12V DC. The voltage measured is displayed on eight LEDs. The inverting inputs (pin 2) of IC1 through IC4 are supplied with regulated 12V DC through voltage dividers R1 through R4. So the inverting input of each op-amp forms the reference voltage. The non-inverting inputs (pin 3) of the op-amps are tied together and connected to the input terminals. The voltage to be measured is fed to these input terminals. When the input voltage exceeds the reference voltage of any of the op-amps, its output goes high, making the corresponding LEDs to glow. This circuit is designed to measure 3V, 6V, 9V and 12VDC.Forinstance, when the input voltage is 3V, LED7 and LED8 glow. When the input voltage is 12V, all the LEDs glow.

Advantages:

1.

2. It has very good temperature stability

.

Disadvantage:

1. Voltage is not displayed on LCD display.

Conclusion: