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Simple RF Remote Control Circuit without Microcontroller

Simple RF Remote Control Circuit without Microcontroller

The article explains how to make a simple RF remote control circuit using ready-made RF 433MHz and 315MHZ RF modules, and without incorporating microcontroler ICs.

With the easy availability of RF modules today making an RF remote control has become a childs play.

It's all about procuring the RF modules ready made from the market by spending a few bucks and configuring them together for the intended results.

Here I'll show you how to make an approximately 100 meter range RF remote control circuit using RF modules, without the help of any microcontroller stage.

To begin the assembly you will have to procure the following readymade RF modules and the respective encoder and decoder chips, for the present project we use the HOLTEKs modules:

RF 433Mhz Transmitter/Receiver Modules

The following picture shows the Rx (left) and the Tx (right) Modules.

The following figure shows the pinout details of the above modules.

Encoder IC = HT12E

Decoder IC = HT12D

The above encoder and decoder ICs do the jobs exactly as per their assigned names that is encode and decode the bit information for enabling easy interfacing with analogue circuits.

After you have procured the above components it's time to put them together.

Assembling the Modules

Configure the transmitter circuit by assembling the Tx (Transmitter) Module with the Encoder IC as given in the following circuit:

Simple RF Remote Control Transmitter

Next, assemble the Rx (Receiver) module with the decoder IC, as per the following diagram:

Simple RF Remote Control Receiver

In the above Rx (receiver) circuit we can see that four of its outputs are terminated through LEDs at the points A.B,C,D and another output which is terminated via the VT pinout of the IC.

The four outputs A,B,C,D become high and latched in response to the pressing of the  four push buttons shown in the Tx transmitter) circuit.

Pin13 switch of Tx influences the Pin13 output of the Rx and so on....

Suppose when output "A" of the  Rx module is activated by the relevant switch of the Tx, it gets latched and this latch breaks only on activating any of the other outputs.

Thus the latch breaks only when a different subsequent output is rendered high through the Tx relevant push buttons.

The output from pin VT "blinks" momentarily every time one of the outputs A,B,C,D get activated. Meaning VT output can be used in case a flip flop is required to be operated.

The above can be very easily interfaced with a relay driver stage for operating any equipment such as a remote bell, lights, fans, inverters, automatic gates, locks, RC models etc.

How to Connect the Address Pins

The pinouts A0-----A7 of the Rx, Tx modules are very interesting. Here we can see them all grounded which creates an impression that these are of no use and are simply terminated to ground.

However these pinouts enable a very useful feature.

These address pinouts can be used for rendering a particular Rx, Tx pair uniquely.

It's simple, let's say for pairing the above modules we ensured that the address pins are identically configured.

Alternatively we could make the above pair unique let's say by opening A0 for both the modules. This will make the pair respond only with each other and never with any different module.

Similarly if you have more number of such pairs and want to make unique pairs out of them, just assign the pairs in the explained manner. You can do this by either connecting the address pins to ground or by keeping them open.

It means by rendering different configurations to the relevant address pinouts between A0 and A7 we can create a huge number of unique combinations.

The range of the above explained RF module is around 100 to 150 meters.

The above simple RF remote control circuit was successfully tested by Mr. Sriram on a breadboard, the following images of the built prototype were sent by him for reference.

Circuit Prototype Images

Making a 433 MHz, 315 MHz RF Remote Control with Relay Flip Flop

Building a hi-end remote control device using very few components today looks pretty plausible. The proposed remote control light switch circuit idea provides you with the opportunity of building and owning this amazing device through simple instructions.

Moreover the unit provides a 4-bit data to be exchanged between the transmitter and the receiver modules.

This Hi-tech remote control light switch enables you to control four individual lights or any electrical appliance for that matter from any corner of your house remotely using a single tiny remote control hand set.

Imagine switching a light, a fan, washing machine, computer or similar gadgets from any corner of your room without taking a step!

Doesn't that sound great?

Controlling a particular gadget remotely through a single flick of your finger definitely feels very amusing and amazing too.

It also gives you the comfort of doing an act without moving or getting up from a particular position.
The present circuit idea of a remote control light switch enables you controlling not only just a single light but four different electrical gadgets individually using a single remote control hand set.

Let’s try to understand its circuit functioning in details of the 433MHz Rx and Tx modules.

Transmitter (Tx) Circuit Operation

I have already discussed the wireless control modules through one of my previous articles, let’s summarize the entire description yet again and also learn how simply the stages may be configured into the proposed unit.

The first figure shows a standard transmitter module using the RF generator chip TWS-434 and the associated encoder chip the HOLTEK’s HT-12E.

The IC TWS-434 basically does the function of manufacturing and transmitting the carrier waves into the atmosphere.

However every carrier signal needs modulation for its proper execution, i.e. it needs to be embedded with a data that becomes the information for the receiving end.

This function is done through its complementing part – the HT-12E 4-bit encoder chip. It has got four inputs, which can be triggered discretely by giving them a ground pulse individually.

Each of these inputs produces coding which are distinctly different to each other and become their unique signature definitions.

The encoded pulse from the relevant input is transferred to the IC TWS-434 which carries forward the data and modulates it with the generated carrier waves and finally transmits it into the atmosphere.
The above operations take care of the transmitter unit.

Receiver (Rx) Circuit Operation

433 MHz Receiver (Rx) Circuit Operation

The receiver module does the above operations just in the opposite manner.

Here, the IC RWS-434 forms the receiving part of the module; its antenna anticipates the available encoded pulses from the atmosphere and captures them immediately as they are sensed.

The captured signals are relayed forward to the next stage – the signal decoder stage.

Just like the transmitter module, here too a complementing device the HOLTEK’s HT-12D is employed to revert the received encoded signals.

This decoding chip also consists of a 4-bit decoding circuitry and their outputs.

The received data is appropriately analyzed and decoded.

The decoded information gets terminated out through the relevant pin-out of the IC.

This output is in the form of a logic high pulse whose duration depends on the duration of the ground pulse applied to the encoder chip of the transmitter module.

How to use a Flip-Flop Relay Circuit at the Receiver module Output

The above output is fed to a Flip-Flop circuit using the IC 4017, whose output is finally used to switch the output load via a relay driver circuitry.

One such flip/flop idea is shown you may construct four of them to access each of the generated 4-bit data discretely and control four gadgets individually.

Whether you use it as a remote control light switch or to control many more appliances……the option is all yours.


About the Author

I am an electronic engineer (dipIETE ), hobbyist, inventor, schematic/PCB designer, manufacturer. I am also the founder of the website: https://www.homemade-circuits.com/, where I love sharing my innovative circuit ideas and tutorials. If you have any circuit related query, you may interact through comments, I'll be most happy to help!

205 thoughts on “Simple RF Remote Control Circuit without Microcontroller”

  1. Hello sir Swagatam,
    Nice update on your website!
    Please do you have any article on your website on ESP8266 Wi-Fi module or associated circuit? If you do, kindly help me with the link.
    Thank you.

  2. Hello sir Swagatam,
    Thanks a lot for the correspondence the past days.
    Please I need your help on the following:
    1. I need the part number to encoder and decoder ICs (that works exactly like HT-12E and HT-12D) that has more than 4 output pins, and that can work with the RF modules in the schematic above. I’ve searched the internet without success.
    2. I need the part number to an IC or ICs (preferably 400series ICs) that works like CD4017. The IC should have different clock input pins and their corresponding output pins in the same IC, such that when a clock pulse is received in one of the clock inputs, it turns on its output and turns off any other output that may have been turned on before it. i.e only one output stays on at a time and any of the input may receive their signals separately.
    I can also make do of an IC that can receive continuous positive or negative signals in its input and and activate its corresponding output and turn off any other output that was previously turned on before it.
    I know that I can achieve this using PICs but I have no knowledge in programming.

    Your response will be well appreciated sir.

  3. Hello sir Swagatam,
    Thanks a lot for this circuit. I have built it and it’s working well with a good range too. I have a challenge though. I want to use the circuit to operate four relays through the four channels, using a transistor driver stage, in such a way that when one button is pressed in the Tx session, the corresponding relay in the Rx session stays activated until the button is released.
    From what I observed after testing, the configuration works in active-low mode. The output of the Rx IC is low on receiving the signal from Tx and high when no signal is received. I have tried connecting it to a transistor driver stage using BC557 transistor, but it didn’t work. I also tried BC547, the same result. The relays latch on even when no button is pushed. Kindly suggest a solution to the problem.
    Anticipating your usual prompt response.
    Thank you sir.

    • Hi Godson, did you connect LEDs with the outputs? if not please do it. LED will give a clear indication regarding the response from the output pins.
      BC557 should work, make sure you have connected its pinouts correctly.
      The supply to the relay should come from a 12V source while the supply to the IC should come from a 5V source.

      • Hello sir Swagatam,
        Thanks a lot for the prompt reply. I have done exactly as you said and I am still experiencing the same problem.
        Here is the situation:
        •For testing purpose, I connected the cathodes of the LEDs to the output of the Rx IC and their anodes to the 5V supply. The LEDs turned on and off as the buttons are pressed and released in Tx.
        •But as soon as I connect the anodes of the LEDs to the 12V supply via resistors, they remain turned on (though a little faint) even when no button is pressed in the Tx. When a button is then pressed in Tx, the corresponding LED becomes brighter while others go off.
        •This same situation plays out when I connect the BC557 through the LED as shown in the schematic above. The LED is turned on faintly when no button is pressed in Tx, which in turn turns on the BC557, and consequently, the relay stays on. I have tried increasing the value of the base resistor of BC557 but no change. When I increase the resistor to a point, the BC557 is not turned on at all.
        It appears as though the outputs of the Rx IC is “leaking” when connected to the 12V supply.

        What can be the cause of this problem and what solution can you profer?

        • Hello Godson,

          I am sorry…that’s right, the BC557 will be always ON since it is continuously getting the biasing voltage through the 5V – 12V = -7V, that’s seriously wrong.

          In this situation please use two BC547 in inverter mode, as shown in the following example image:


          Replace the LED/resistor with relay coil/diode….make sure to connect the relay to the +12V supply, while connect the remaining left side positive line with +5V.

          ignore the preset and the 33K resistor, and connect the left side BC547 base with the IC’s LED/resistor output.

          Let me know if you have any more doubts

          • Thank you very much for the response sir.
            I have connected the outputs of the Rx with the circuit shown in link that you provided. I removed the 47k pot and the 33k resistor on the left and connected the output of the Rx IC through the LED/resistor, to the BC547 at the left. But the result is the same. The relay stays on whether a button is pressed or not. I removed the second 33k resistor in the middle and the relay stays off even when button is pressed in Tx.
            I then decided to use only one BC547 with a 1k base resistor, and the relay stays on when no button is pressed, and goes off whenever the corresponding button is pressed. But that is not how I want the circuit to work. I want the relay to turn on only when a button is pressed.
            I believe that there must be a solution to the issue.

          • Wow!
            It’s working perfectly well now after I implemented the modified design of the transistor driver. Thank you so much for your assistance sir. Keep up the good work!

  4. Hello swagatam,
    awsome site, im glad I stumbled upon and well written, TY

    my question is for the pin outs,
    I see in the actual pic of modules the Tx has identifiers on the back side witch matches your drawn pic for pin id, does the Rx module have to same identifiers on its back side ?
    if not, is your drawn pic of pin identifiers done by viewing the Rx from its back side (none circuit side) ??
    just like the Tx reference..

    TYTY in advance, P1nki3

  5. Thank u Sir for this information..

    Nee some help and advise based on this circuit.

    Im working on a micro rc plane which will be controlled using 2 motors. The Tx will have 2 joyticks one for throttle which controls speed for both motors and one which will speed up each of the motors depending on joystick position.

    My questions are.

    1) Can i use the above circuit for the same and what modifications would i have to make for joystick and motors. Will this circuit accomodate PWM signals?

    2) Can i use potentiometers as my joysticks or any other alternatives?

    3) can the range on the RF modules be increased? Would an antenna help substancially?

    Deeply appreciate ur help in these matters

    My email is rohandsequeira@gmail.com

    Thank u Sir.

    • Hi Rohan,

      yes you can connect PWM and pot control with the above RF module Rx unit, and control the motor output at the Tx side accordingly, but I am not sure how a joystick could be configured with a pot?

      The range can be increased by increasing the Tx antenna length using a 1 meter flexible wire or a telescopic antenna.

      I have already discussed a similar concept in the website, you can refer to the following link for a better understanding of the concept:


  6. Sir, can i use this circuit with pwm signals to have a potentiometer instead of switches at tx end and use the pwm signals to drive motors at rx end? Would the same circuit work?

    What i i want to drive 2 motors and change the speed of each motor or wen shut one off and let tw other run.. How do i modify this circuit for that?

    Also what beat range will i get from the 433rf units if i attach the 17.34cm antenna on both ends?

    Much appreciate all the infprmation.

    Thank u Sir.

  7. hello swagatam i'm shubham

    i build the circuit using rf technology with pic controller to turn on the light through relay

    when i press the key from the transmitter side there is no quick repose across the receiver to turn the light on i need to press the key continuously for more then 5 times after that it is turning on so

    sir im not able to find out the problem is this problem causing by the hardware or by the software and i tried with different baud rates like 9600bps and 4800bps so sir how i can avoid this problems please suggest something

    • Hello Shubham.

      If it's a MCU based then it could be difficult to troubleshoot through assumptions, since the problem could be obviously in the software section or the coding.

      If you have programmed it then I think it shouldn't be much difficult for you to track it down

  8. Hai sir….
    I have few ? Sir…

    When Tx 1 button active means Reciever output D0 output will be postive or negative..

    For one tx pressing second it will work or it will latch it sir

    I'm going to use this circuit in CD4017..
    .If Rx D0 o/p postive means shall i connect 14 pin in cd4017…
    In the between of 4017 14 and RX DO pin i use one diode IN4007…is it correct sir…

    Whether the D0 o/p negataive means shall i 470ohms resistor and 557 transistor…

    Pls give the solution sir..

    • Hi Kesava…in the above circuit the output from the Rx was tested to be negative when triggered…and positive normally when not triggered.

      you can connect the 4017 pin#14 directly with RX outputs but due to the opposite effect the 4017 flip flop will toggle only when you press and release the Tx button.

      do not connect any diode or resistor in between the Rx output and 4017 pin#14.

  9. Hey, how do I do that when I turn on the light in the room, the LED output is on and when I turn off the light in the room, is turns off the LED output? TX module wanna be powered directly from the light. That is, when I turn off the light, TX module power is off and also the state of the RX LED changes. Thank you.

    • …you can do it by replacing the switch points with BC547 Collectors/emitters.

      the bases could be connected at the junction of an LDR and a 220K resistor. 220K end would go to the ground…and the LDR end to 5V supply

  10. hey how hard can it be to make the same job from scratch i mean using oscillators , modulation circuits , antenna … in much lower frequencies 5 mhz ?

  11. Well Sir, I just breadboarded your circuit an could not light any of the four LED…A,B,C,or D..The led for VT blinks so I know there is some transfer, but I am not sure what to do next.

    • Caleb, check the polarity of the LEDs, it must be exactly as shown in the diagram….by the way unless the points A,B,C,D are connected with some source the LEDs will not show any response….so make sure these are connected to a transistor driver stage…… or for testing purpose you can connected them with the supply rail of the circuit.

  12. Dear Swagatam,

    I really enjoy your site. Thank you.

    I have built your RF circuit (Simple RF Remote Control Circuit without Microcontroller).

    I work well. The led light up when a button on the transmitter is pressed.

    I would like to add a relay to each output on the receiver which should be latched until the respective button on the transmitter is pressed again (On/Off).
    What do I have to add/modify in order to make this work?

    If I set the address like this:
    Transmitter pin 1-8 to ground
    Receiver one of the pins 1-8 not to ground and turn on the power an led on the receiver lights up and keeps so until I change the address.

    How does that come?

    Thank you in advance,

  13. Heelo Mr SWAGATAM MAJUMDAR, can you please inform if is possible use your example, but running in 16 outputs not 4 outputs, like this post? regards

    • Hi Paulo, yes you can use the same set-up for a 16 channel Rx/Tx module also, just repeat the suggested configuration for the all 16 i/p, o/p pins

  14. Hello Swagatam,

    I wish to use the output of VT to close a small 12v circuit but I do not want to use a relay. Can you tell me the voltage and current at VT when the signal is received? I want to try and use an SCR to close the 12v circuit

    • Hello Dan, you can connect the free end of the 360 resistor with the base of a NPN transistor, and connect the emitter of the transistor with the ground rail.

      Next you can connect the 12V circuit between the (+12V rail) and the collector of the NPN, and make sure that you join the 12V negative with the 5V negative of the above circuit

  15. Hello sir.. I have to do rf remote controll transmitter and receiver. At receiver i have to use Pic16f877a and to drive motor on the rf remote controll. What should i do? Please suggest me.

  16. Hello, very thanks for the post!!! If i need to make one project using your idea with hts 12 to control 16 relays, is it possible? can you show me one simple application of these if is possible? regards

  17. normally this circuit is used to give latched output.Means works as a toggle switch or oN/OFF switch.Can we use some outputs as On when pushbutton is pressed & Off when pushbutton is released.
    What do we call such output technically?

  18. dwagatam ji i checked the circuit .
    this problem is present for every car center lock.

    i need solution for RF 434.
    can i add circuit on RF 434 module to remove noise.
    or i can replace RF434 with RF 315..
    i want to use RF modules .
    here is any solution or upgradation of circuit.

    • Prashantji, so does it mean jamming car remote systems is so easy? It looks very strange.

      anyway, as far as modifying is concerned these remote units are embedded units and cannot be modified in anyway, so there's no external solution available for the issue.

      yes you can try replacing it with RF315 this could make a difference…

  19. thank u swagatam ji .
    plz send me link of fm based ordinary transmitter and receiver circuit.
    fm base transmitter and receiver can give code for different systems.
    and 40 meters range in home conditions.

  20. Dear swagatam ji actual problem with RF receiver and transmitter is.
    we r making water pump controllers for domestic pumps using RF 434 with coding ht12e and ht12 d.

    problem is if i fix wireless system at any home.
    the wireless works properly .
    but its range effect jam all the center lock of car in range.( centeral lock remote not work till RF434 on).
    what is the prob with RF434 mhz
    i m use red modules with rohs approved.

    • Prashantji, Then it's the problem of your car remote control, you should complain this to your dealer from where you purchased the car security system….because these units are supposed to be immune to all forms of RF waves which are not directly matching their specified wave frequency.

      or possibly you can quit the RF module remote control for the water level controller and use an FM based ordinary transmitter.receiver circuit which will not interfere with your car system

  21. Dear swagtam ji
    I m using this circuit

    Rf434mhz with ht12e and ht12d.
    Here is big problem.
    If we supply the receiver and transmitter .
    Car centeral locking system remote not works in wireless range.
    Plz send me solutions

    • Dear Prashantji,

      First try it on table and confirm the working, after this you can try it inside the car.

      Put a long antenna with the receiver unit, this could be a two meter long flexible wire joined with the existing antenna of the Rx unit.

  22. sir help me about one light off because suply off automatically but again supply on second light on not a light first.these drawback remove .why?

    • do you mean to say that you want the outputs to latch and hold when the relevant remote buttons are pressed?

      sorry that may not be possible in this module, you may have to buy ready made modules which normally include a selection option for the output modes.

  23. Hi Bruno, you can get it from any online parts dealer.

    for getting a positive logic you will need to invert the output by using NPN transistors across the 4 outputs or by using NOT gates.

    • four led connected by using rf remote control switch,first light on after sometime supply off but again supply on swtich on light second glow not a first light why.this drawback remove name of component remove from this circuit

  24. Hi Majumdar! can you tell me were i can buy the tx and rx modules?on rx module it is possible to have outputs with ground connection pulse?
    regards, Bruno

  25. i'm working on the amplifier but it is hard to find transistors working at 433mhz frequency, developing a transmitter module operating at fm band as receiver boards are readily available, i need fm transmitters with crystal oscillators, any crystal fm bug circuit sir ?

  26. sir range can be increased by rf wide band amplifier at transmitter side we can increase its range ,without modifying circuit simply use an 12volts pencil cell for the transmitter(cell used in car centre locking system) i referred the data sheet for 12volts db is increasing

  27. Hello Sir,

    can you guide me an simulator software where i test this circuit.I use proteus 7.8 but there is no RF module in its library.. can you guide me.. kindly reply me thank you

  28. Hi Mr, what is the difference between a simple resistor 1k and a 1k x 4nos resistor? a ceramic resistor? can I replace it with a simple resistor? thanks

    • power supply is 5V.

      the 2 way remote control article which you referred does not have a clear explanation or a diagram so it won't be feasible for me to elaborate on that.

  29. Hi Swagatam,

    I was wondering? :

    1. The pins from A0-A11/1-8 & 10-13 of the HT12Encoder, are they all switches? I mean for basic wireless on/off switch?

    2. If yes, how do I add more switches? Will I add 1Kohm resistor with one end connected to pin 18/VDD and the other end to pin A0-A11/1-8 & 10-13?

    3. Better yet, can you modify the whole ciruit to make remote controlled car?

    * The circuit should consist of:
    -Motor A & B
    -Switch A, B, C, D
    -Press switch:
    -A: Motor A turns clockwise
    -B: Motor A turns counterclockwise
    -C: Motor B turns clockwise
    -D: Motor B turns counterclockwise
    -Decoder/Receiver cricuit

  30. Hi swagatam, thanks for the detailed reply, i am now in the soldering stage (learning). will update once it is done.

  31. Hi swagatam, i want to use the above rf circuit for remote brake and indicators lights on a helmet. How do i trigger s1 thru s4 as supply voltage is 12v in bike and powers only when brake and or indicators are swicthed on. regards rajanikanth

    • Hi Rajnikanth, for the Tx unit you will obviously need a battery in the form of a button cell or any other similar type….. for the Rx unit you can use a 7805 IC for converting the 12V to 5V.

    • …if the Tx is also intended to be installed in the bike then too identically you can use a 7805 IC for stepping down the supply…

    • hi, thank you for a speedy reply. I will now install separate batteries for both Tx and Rx modules. I want to know if I can connect the brake light, turn indicators (left and right) wires which will carry 12v directly to D0,D1,D2??? Please help me out here as this project is for all my helmets and bikes.

    • Hi, continued from previous post, can you provide schematics of how the 12v line can be used to trigger the s1,s2,s3 switches. regards rajanikanth.

    • I can publish it in the form of a new article with all the required details in it so that you can make it exactly as per the given info, however before that I would want you to provide me the whole application detail regarding the circuit, meaning how and why do you intend to use the units in your bike, this will help me to design the circuit correctly and entirely.

    • Hi swagatam, This circuit is for a helmet mounted remote brake and turn signal indicator. I bought one from ebay but ended up breaking it in a crash. the following link will show the model that i had (www.ebay.in/itm/Wireless-Helmet-LED-Break-and-Turn-Light-/291497878507?pt=LH_DefaultDomain_203&hash=item43dea0a3eb). When the brake is depressed, the three leds on the module light up, when the turn signals are activated the amber leds in the module light up. I have checked the previous project for this same application using a doorbell or using an fm radio, but i like this rf module better. Regards rajanikanth

    • Hi Rajnikanth, you can take the help of the following article:


      In the first diagram, ignore the circuits with the yellow colored gates, we don't require those. refer only to the Tx circuit, the four switches can be replaced with the contacts from four separate relays…the coils of these corresponding relays can be now simply connected with the relevant bike lamp terminals…so when these lamps are switched ON, the particular relay also triggers sending a RF out from the Tx circuit.

      For receiving this signal, you can use the second circuit shown at the bottom section of the article…..in this circuit eliminate the relay and replace its position with LEDs
      as you can see only one channel is used in the diagram…you may use all the four outputs and repeat the transistor drivers stages with its own set of LEDs

      these four LED drivers will respond to the four relays whenever any of those are triggered, the relevant sets of LEDs on your helmet will be seen illuminated

  32. hello swagatam, i'm vedavyas can we make a wireless switch which operates over 1km range
    Is there any circuit for that

    • hello sai, you'll first need to build or procure a 1km range Rx/Tx unit, after that we can modify these into a remotely operated switch design.

  33. it cannot be modified because the ICs are internally set.

    an RF long range transmitter can be tried, the FM receiver then can be modified for activating a relay.

  34. then can you have any idea how to increase the range of this circuit or else do we have any other circuits for controlling more than 1km range

  35. Sir,I have made this ckt and it is working.But initially all 4 outputs are HIGH and when I press a switch the output goes LOW.Can I reverse it?
    Also can u pls xplain how to connect it to relays using L293D..When I connected ,all outputs are initially high and relays are ON.The working is just opposite.
    Please help.I am doing this as my mini project.

    • Mohammed, you can use 4 PNP transistor like BC557 and connect it with the 4 outputs for reversing the effect.

      the bases will connect with the IC outputs via 1K resistors, emitters to positive 5V and the collectors may be then used for getting the reverse responses.

  36. Hello there, I tested the circuit again as I make a mistake before at TE pin . so here the result when i push the button the LED go off. How do I make the result push to on and not push to off? any idea/ suggestion?

    • Hi TD, yes it looks like the modules are working OK now…

      I think you may have to refer to the datasheet of the ICs, I am sure somewhere this feature of the modules will be mentioned there…what you are experiencing is just one of the features of the modules and there should be certainly a changeover mode that could be implemented by doing some easy mod in the circuit….

      please try and look for the datasheet for the remedy.

  37. Hi there Swatagam Majumdar, today I bought a new transmitter and receiver and try it on the circuit and boom there is a result. ITS WORKING!!!! Im so happy.

    I used NT-R03C-LF as receiver and NT-T10A as transmitter. So the problem before was caused by the module. By the way I got something to ask. Why is it the LED at output maintain on even i already open the switch? Is it the output latched? how to make it not latched?

  38. There is one question, does the type of power supply effect the circuit? im using ic 7805 to convert the 9v battery to 5v and its DC.. do I need to use AC as power supply?

  39. Hello there sir, I tried your circuit but it didnt work too.. when i connect the circuit to the power supply the LED didnt turn on at all even when the switch at transmitter is on.. I want to show you the picture of the circuit. Can you leave your email here sir so that I can email you the picture?

    • Hello Team dare

      Do the following test procedures:

      Connect two LEDs across one of the selected Rx outputs. One LED from positive to the IC output pin and the other LED from output to ground, make sure both these LEDs have a 1K resistor in series

      Now press the corresponding button of the Tx and see the response on the LEDs, initially one of the LEDs will be ON, on pressing the Tx button will flip the other LED ON shutting off the previous LED….this will prove the correct working of the circuit….if not then some other serious fault could be anticipated

    • Hello

      I tried the test procedures,
      Both LEDs at selected output is Off initially and then i press the Tx button the LEDs still off and i hold the button for few minutes suddenly both LEDs goes on and when I open the Tx button the LEDs still on.

  40. Aw i type so long to comment and it was blocked as there is an external link to show my circuit as it was not refered from your circuit….hmm ill make it short.


    Hello there sir,

    The output D0-D3 at HT12E is connected to 5v, can you explain the function?
    The capacitor C1 is used for?

    Im using a different receiver, there was 6 pin for VCC, RXD, GND , SHUT , GND . ANT.
    i tested the receiver with multimeter and the reading is the all the pin connected to each other using continuity and ohm test.. is it normal?? I bought 2 of them and both is the same..for your information the receiver model is CWC-12 and the transmitter model is CDT-88..

    I hope i get a respond from you..thanks

    • Hello Team dare,

      For all these details you may have to refer the datasheet of the ICs, because all the parameters are entirely designed and specified by the chip manufacturer.

    • Thanks for your respond sir.

      For these 2 questions
      "The output D0-D3 at HT12E is connected to 5v, can you explain the function?
      The capacitor C1 is used for?"
      i refer it to your schematic.

      and what i mean with the receiver is the receiver module. I referred to the data sheet and it showed that rxd is the data output and shut is enable which is active low.

      Did you see my circuit? 2.bp.blogspot.com/-shfJy0DaSyY/U89hfFyhSqI/AAAAAAAAABg/1cZIrS4cIyQ/s1600/1.png

      The differents of our circuit are the position of resistor before the led, the capacitor and the 5v connected to the HT12E output D0-D3. I want to know the function of that so i can modify my circuit. Thanks sir.

    • Inputs of digital ICs cannot be kept open and hanging, therefore D0-D3 are terminated to the 5 V supply. C1 could be decoupling capacitor for ensuring proper switching of the IC.

  41. Thank for ur reply..! But as i read it datasheet. Its max power supply is 12v, and the and the Rosc is vary to the fosc and power supply accordingly to graph, but m not clear abt reading this graph. And it say that if the enable pin active, it contineusly scan and transmite as cycle..

    • don't bother about all those things, the operations are actually very simple as explained in the above article, I have used these units myself without any difficulty

      ….give me the datasheet link, the Vcc is normally 5V for these chips.

    • ….yes it sends unique coded signals every second to the Rx… it's the special feature of these units, it ensures that the RF signals stay unique continuously and becomes impossible to decode by any other nearby bugged system.

    • There are two variants, one uses 5V max and the other 12V max….but 5V is the optimal range for both the units, it depends on the user what supply range suits him better,

      for the 12V unit you can use a 7812 to be extremely safe.

  42. hi sir! i feel confuse with this two ic.. i have search many site about this.. some connect input of tx to Vcc n some connect to GND( switch D0-D3 ). does the output still the same? the output of the rx is the the same to the input of tx or inverse( like ur circuit when input go low the output go high).
    one more, in ur circuit, when press D0 to low, does the output go high until the new code has recieved or just go high for a while recieving code?
    about TE pin u had connected it to gnd directly. it means to enable it forever? does it keep transmitting to the rx even the swith is not pressed( D0-D3=high) ?
    i have a pair of rf module label 315-330-433mhz. the tx module has the range up to 200m if use with 12v. if i use ic above with 12v. what the value of Rosc should i use?
    for multi output can i use BCD to decimal converter at output to get 16 channel? if can which ic number?
    i was blur with this for long. plz help me..

    • Hi Seok, when Tx switch is pressed, the Rx outputs become low….I think LED direction in the above Rx circuit is incorrect, it should be in the opposite direction meaning the cathode of the LEDs should be toward the IC pins and anodes towards ground.

      TE is permanently connected to ground so that the circuit stays always enabled and ready for the button-press activation. It will transmit only when button are pressed.

      The above circuit will not work with 12 supplies it's rated for 5V supplies only.

      For 16 outputs you will have to use a 16 channel module, these are similar to the above except that they will have 16 outputs and buttons.

  43. sir i want to make an model which alarms me only when water tank is full…and will it be effective if i use it between 3 floor and ground floor…?…..can u tell me tx and Rx that will be effective…

    • Anish the above explained design will work for your application as well, use only one of the outputs from the shown 4 outputs.

      An amplified buzzer could also be a good option for the alarming, which will allow you to use an ordinary amplifier circuit instead of complex wireless Tx, Rx.

  44. sir i would like to adapt this project but im having trouble with the output part…could you give me the extended circuit where the output part has four loads namely pure light bulbs..

    thank you sir…

    • Genevive, you can refer to the following circuit for a better understanding:


  45. Hello sir,

    Please tell me what is the output if more than one tx switch press in one shot??
    Either 2or 3 or 4 ?

    Is all LED will glow or only one will glow?


  46. Hai, I made two sets of circuits. One set with 433mhz and another set with 315mhz. One board consists of 433mhz TX and 315mhz RX. Another board consists of 433mhz RX and 315mhz TX. The two sets of circuits working good when they are in shorter distance. I kept the two boards at seperate distance of 20 meters. Now when I connect the antenna in 433mhz TX and RX means, that circuit is working good. Then I disconnected the antenna from 433mhz TX, RX and connected the antenna in 315mhz TX and RX means, that circuit is working good. Now if I connect the four antennas in the 433mhz TX, RX and 315mhz TX, RX means the LED at the pin17 of th encoders are blinking (means the RX is not able to catch the signal properly). The two modules frequencies signals are interfering with each other. so the circuits are not working properly.I tried by changing the directions of the antennas, but still negative only. Pls suggest me a solution for these…

    • sorry no ideas, the RF modules are embedded systems and with so many frequencies messing around, it could be extremely difficult to determine the exact fault…

  47. In my Rx unit there are 2 DATA pins. can i connect two data pins together and finally connect the pin 14 of HT12D ?

    • I did not understand what you trying to do,
      anyway data pins should not be connected with each other directly.

  48. Thanks for the quick reply. i will make remote control sliding gate during next week. Let u know if any prob happens thank you.

    • yes 12V relay can be used but the 12V supply will need to be given separately to the relay.

      use the given formula for calculating the resistance value….you can try 10K, not 56K, it's too high.

  49. Hi Chandrakant, I don't think it's possible because the chip is preprogrammed and cannot be altered externally.

  50. hiii swagatam, is there any way to increase its range or any other module available having range more than 500mtr? plz rply soon

    • Hi, Is everything working correctly? Please let me know the results of the units, meaning how the relays are working and how the water level controller is responding, if possible with pictures.

      It will help me to design the new circuit correctly.

    • There is prob in the water circuit… I connected a CFL bulb in the relay… when i power on the circuit, the bulb is always in ON state because sensor B and C are not in touch. Even though I short circuited the sensor A and C, the light is still in ON state only. Pls help…

    • please send the close-up picture of the circuit that you have made, I'll try to find the fault by seeing the connections, if possible.

    • Hai, Ignore the previous command. The water circuit working good… The problem was due to loose connection. And now its working grt…

    • Hai, Now one prob in RF circuit… when I power ON the RF circuit, The four output LEDs are in ON state only. And when i press the s1 switch means the output D LED is goes off, if I release the switch s1 means the output D LED is in ON state. Like that four LEDs are working. Its reverse order. I need if i press the switch means the corresponding LED should wrong. Is there any wrong will be in my circuit?? Pls help..

    • …please send pics if possible, so that I can post them in the above article……do it only if it's convenient for u….no force.

    • Thanks Mr.swagatam… I changed the polarity as u said… now it is working correctly…
      Below are the pics:-

      Now waiting for the integration of the circuits…

    • Thanks Sriram, I'll use the images for the above article.

      I'll try to post the relay integrations soon and let you know….keep in touch meanwhile.

    • sorry. Am not able to get a clear idea for connecting the two circuits. Can u able to provide me a circuit diagram for connecting the two circuits?? If water level goes below D0 means motor should power on, D1=half tank ( LED indiactor), D2= 3/4 tank (LED indicator), D3= full tank( LED indicator) and motor should shut off when water reached the D3 terminal. Please help…

    • It will be a little lengthy circuit, I will try to present it in my blog soon, in the meantime you can make both the circuits and keep them ready for the final integration as per my diagram.

  51. 1.In this circuit, u shown up for 4 input and 4 output. Is it possible for 5 input and 5 output?? If yes means how to modify the circuit??
    2. I am planning to implement this circuit for my home over tank. Bocz am in 1st floor and tank is in 5th floor. In the above circuit, Instead of the push switches in the transmitter section, if i arrange the terminals D0-D3 inside the tank means, as the water raising, the one by one D0-D3 wil get in contact through the water and this wil transmit the signal to the receiver. So the output LEDs in the receiver wil turn on according to water level.
    3. In transmitter, suppose D0 is the tank empty state means there will be no contact to none of the terminals inside the tank, so the LED in the D0 of receiver wil turn off, at this state the motor should turn on.
    4. After the water level started raising, the D3 of the transmitter will get contact , so the D3 LED of receiver wil turn on . At this state the motor should turn off.
    Please provide me the circuit for this…

    • The above circuit cannot be modified for 5 outputs, you can Google for a 5 output Tx/Rx circuit, you may get it.
      Or you can buy the modules readymade from the market.

      The input switches can be attached to relays and toggled through water sensor circuits.
      We will discuss the circuit later, first you arrange the transmitter modules, we'll proceed further once it's done.

  52. that you would using such a RF receiver could make a tester for car remote control?
    Suppose that the DATA line is closely linked to the transistor, which would include the LED when the receiver receives a signal from the remote control?

  53. you can use the same circuits and configure them to work with different frequencies by setting up and matching the pins across A0 to A7 of the respective Rx/Tx pairs.

  54. It's greate, but where can i buy it or what is the name of the module because i cant fint it. Mabye its because i'm living in the netherlands

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