RF TRANSMITTER SECTION
Today we are going to discuss about the simple RF (Radio Frequency) Transmitter and Receiver circuit.
RF(Radio Frequency) is a High Frequency signal commonly used for communication applications, due to its high frequency we can transmit signal to a sufficient distance (about 300 Foots) without attenuation.Here, the simple RF switching circuit is used to turn ON and turn OFF an LED (For Demonstration) you can replace the LED with a switching RELAY and control any appliances.
CIRCUIT DIAGRAM OF RF REMOTE SWITCH
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| Circuit Diagram RF Transmitter |
Let me introduce you the Main components used in this RF Transmitter Circuit.
HT 12E
It is an Encoder, which is used to code the signal generated in circuit, signal means ON and OFF position of switch S2.
The Transmitter section includes 2 SWITCHES, S1 and S2. Switch S1, is configured as Transmitter enable, this determines the condition of Transmitter. This should be always closed to transmit the signals. Switch S2, it is used as the control Switch to turn ON and turn OFF the LED.
RF RECEIVER SECTION The RF RECEIVER SECTION includes,
CIRCUIT DIAGRAM OF RF REMOTE RECEIVER
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| RF Receiver Circuit Diagram |
ASK RECEIVER
It helps to collect the transmitted signals from RF TRANSMITTER through the antenna and give it to decoder input.
HT 12D
It is the Decoder IC in the RECEIVER circuit, which will decode the information transmitted from RF transmitter. It is just reverse operation of the Encoder.
FlipFlop IC 4017
It is a Flip Flop Ic, which will turn on for the first signal and turn off for the second. The working is same as that of a BI-Stable Multivibrator.
what is the distance it can cover please give reply
ReplyDeleteThis circuit covers a distance of about 300 foots.
ReplyDeleteWhere can I purchase the flipflop ic? any websites? thank you
ReplyDeleteTry to buy it from any electronics store near you......
ReplyDeletethank you! also for the capacitor is that mili farads or micro?
ReplyDeleteYou are most welcome...... The capacitor is in microFarad Range.
ReplyDeleteI want to increase the distance around the 1000 feets what is the change that i have made in circuit......
ReplyDeleteIf you want more range, its better to try a GSM module.....
ReplyDeletesir i want use remote in weighing scale please guide me
ReplyDeletesir i am use IC 78e052. how to connect keypad by remote
ReplyDeletesir Im wondering on how to tweak this circuit to having two devices with unique data but the output would still be the same, turning on and off of the led, but the other remote would not be able to communicate with the other receiver.:)
ReplyDeleteThe Communication between these two sections (Transmitter and Reciever) is made possible by transmission of a Binary data (For eg:- 0100) via RF.
DeleteSir may I ask how can I connect a relay to the receiver circuit? I am planning to control a vibrating motor. thanks for the help.
ReplyDeleteTake the output from positive terminal of LED (Receiver) and give it to the base of an NPN transistor (BC547) with emitter grounded and the relay should be connected to collector.
DeleteWhen the output triggers, the transistor turn on and enables the relay.
Thanks for your reply.I have one slight problem. When i create two unique remote control..having different binary data..the problem now is, the other wont work if the other remote tranceiver is turned on even when they have different binary data..possibly an interference?how do I solve this?
ReplyDeleteYou can simply solve the problem by coding the Encoder and Decoder of Transmitter and receiver.
DeleteLets look how to do this,
The address lines for both encoder and decoder should be equally connected.
That is, if you connect the address line 2 of encoder to ground, that same line (pin) should be grounded at decoder.
This makes the transmitter and reciever unique.
1-8 pins are address lines for both encoder and decoder, you can use any of these pins for grounding but do remind, both of them should be same.
I have two remote transmitters and one receiver. the other remote has different address data as for security purposes. But when 2 remote transmitters are enabled, the couple transmitter with the receiver wont work unless the other transmitter is turned off..how to fix this?
ReplyDeletePlease read my reply to Roger... It may helps you too.
DeleteYes, I have done that..One transmitter with address hung up. and another transmitter with address0 grounded, and all other addresses are hung up.. My receiver's addresses are all hung up to..No address thats ground, which means that my transmitter 1 and receiver should communicate.I do not have any problem communicating the two..and the other transmitter doesnt communicate with the receiver since it its addresses do not match..My problem is that when both transmitters are set to ON(transmission ENABLED), the transmitter 1 could not communicate with my receiver. I should first turn off the transmission enable of transmitter 2 bfore the transmitter 1 and receiver could communicate.Why is that so?
ReplyDeleteI think, that's because, you are using same RF Module (ASK of 433MHz) on both the Transmitters.
DeleteI see..so no other way but to turn off the other transmitter or, to change its frequency right?
ReplyDeleteI think so.....
DeleteAnyway Wishing You All The Best.
sir, please help me. i'm on a project that goes like this. there are three transmitters scattered on a house and a receiver. when one transmitter is switched, the receiver will vibrate and the LED will indicate where the signal came from. the same goes for other transmitters. each transmitter has a corresponding LED color but they all trigger a single vibrating device. how can i work on this project? thanks sir.
ReplyDeleteYou can use 3 transmitters like the circuit shown above.
DeleteFor the three transmitters T1, T2, and T3.
The control switch S1 of first transmitter T1, should be connected to the 10th pin of Encoder IC (HT12E).
Similarly switch S2 can be connected to the 11th
pin of second transmitter T2
Like wise you can use upto 13th pin.
In the same manner, you can get the output from Reciever, HT12D of pins 10,11,12,13 for the corresponding transmitters.
sir, how can i connect the three corresponding LED for each transmitter and the vibrating device in the receiver circuit?
DeleteConnect the first transmitter as shown in above circuit for the second transmitter do the same with just one change,
Deleteconnect the 11th pin to base of transistor and do the rest as same for first transmitter.
I think you get my point.
sir is it possible to add a voice/speech/noise sensor to the transmitter circuit. when the transmitter senses a voice or noise, the receiver is triggered. but the switch is also present. The receiver can be triggered either by noise or switch. I'm thinking of putting the receiver near a telephone, once the telephone rings it alerts the receiver. Thank you sir.
ReplyDeleteYes its possible, you can combine a sound sensing circuit (may be Clap switch circuit works better) at the switching side of reciever section.
DeletecaN i replave the 6v batteries with other value of supply voltages like !2 volts or higher?
ReplyDeleteYes you can use a 12V supply together with LM7805 Regulator.
ReplyDeleteHello Sir!
ReplyDeleteI am working on the similar project bt only difference is that my operating frequency is 2.4Ghz and on the receiver side there is motor which i have to turn on and off;so wat wil be the changes in above circuit?....Please suggest me....waiting for your reply...praj
Is 2.4Ghz Your Transmission frequency.......???
ReplyDeleteYes Sir...both transmission and reception...kindly help us!!!
ReplyDeleteThen, Use a suitable modulator and demodulator for transmission and reception of 2.4Ghz signal. Here i am using 433Mhz ASK modulator and Demodulator.
ReplyDeleteI am using Xbee rf module for this purpose bt now m facing the problem of how to disconnect the load ckt from power supply(mains)..and here m using motor as a load...so what should i do?
ReplyDeleteHey what's the battery life like if not using the switches often? Same as most automotive key fobs?
ReplyDeleteSir,How cost for the components?kindly reply me,
ReplyDeleteThe total cost will be within Rs700.
ReplyDeleteSir,i got an equivalent board (RoHS). That is too small. Have any problem to giving 6v as its vcc? Pls help me.
ReplyDeletesir,can i know the specifications of antenna?
ReplyDeleteHere In this Circuit, The Antenna is an optional one. You can simply ignore it if you don't have.
Deletehow to make it
ReplyDeletetwo channel
Can You be more explicit....?
Deletei need to control two different motors
ReplyDeletethanx for u reply
Please refer the comment 12.1
Deletethere is any need of programming in the ic
ReplyDeleteNo Need of Programming the IC
Deletehello sir please help me, i want to control multiple relay can i do with this circuit or please guide me to make rf based multiple relay board.
ReplyDeleteAt the reciever section, HT 12D pin 10 is connected to the base of transistor, you can change it to pin11, pin12 or pin13 also change the switch in HT 12E in transmitter. In the same way you can connect multiple relays.
DeleteThankyou sir for the guidance but sir i have a doubt that would i need multiple flipflop IC for multiple relays? And what other components would i need? Pls guide me with a figure if possible. Thanks.
ReplyDeleteYes You are right. You should have multiple flipflop ics. Wire the circuit same as flipflop1.
DeleteSir, which type of relay i can use here, any specification? Pls guide me.
ReplyDeleteThank you for the information. I need a receiver of minimum size with a relay output (contacts rated at 20ma at 6 - 12 vdc). What would be your estimate of the minimum receiver dimensions (L, W, H) with a 30 foot range?
ReplyDelete