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Make a Hi-End RF Remote Control Circuit

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. Build the “amazement” right on your workbench.
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.

Circuit Description

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.

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.
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.


48 Comments

  1. hey i want to switch Led on when pressing the keys and off when keys arent pressed on encoder(data pins grounded)..
    plz tell me how do i do that ?
    very Urgent..

    • Suppose you connect pin10 data switch to ground,, then pressing the On/OFF switch will activate/deactivate the pin10 of the receiver(decoder) unit. The trigger will be ON as long as data switch at pin10 of the encoder remains ON….

  2. Hello sir,
    i find dis circuit very intresting bt i have some doubts.
    Firstly, i am using ir instead of 434 so i wanna know what frequency pulses r comming out of "dout" pin of transmitter and how to calculate that ?
    Secondly, since ht12d responds to encoded signals; so is this system immune to false triggering due to light levels ?
    And lastly, i want latching function on all the 4 outputs of decoder so i am thinking to use four 4017 ic (each on one output) as per the configuration shown in one of your post about "making an ir remote controlled motor".
    Is there any other way to achieve the latches with fewer components ?
    I also thought of using cd4042 ic with 4 d-flip flops in one ic for this purpose but it is not available to me.
    Sir, Can you please clear my doubts ??
    Have a gud day ahead !!

  3. Thank you sir for your valuable reply.
    I am sorry i didn't mention it before that i want the circuit to latch with a trigger signal given by ht12d and when it gives the signal second time it should unlatch the circuit. same which you did with 4017 and 4093 ic. any other suggestions besides these two.

  4. Ok sir thank you for your suggestion. i will go for it.
    Sir can you give me an approximate idea of how much ht12e, ht12d, 4017 and 4093 cost (round about value) so that i could make my pocket ready.
    Regards,
    deepak.

  5. Hello sir,
    Can u suggest me some other flip flop ic which can be used for all four outputs of ht12d instead of 4 seperate 4017 flip flop circuit to make circuit compact. (Like 4013 )
    Thanks

  6. Thanks,
    but here I m little confused.how could I implement this to activate and deactivate relay by single input.I.e. as we do in 4017 latch circuit momentry high pulse on #14 latch relay next momentery high pulse release latch.
    If u please publish a tutorial on it In ur blog it would be very helpfull to me and to all of ur followers.

    Thanks

    • Hi Avijeet,

      I am afraid IC 4043 will need two separate inputs for toggling the relevant output ON/OFF, it cannot be done with single inputs.

      You can try making separate flip flops using IC 4093, it will respond nicely to single inputs or alternatively you can use separate 4017 ICs for the same.

  7. Hi Swagatam,
    The diagram for the receiver seems to be wrongly positioned in the write-up; you may wish to re-position it . . .
    Also, any suggestions on sourcing the chips TWS 434, RWS 434, HT 12D, HT 12E? Shops, mail-order sources (preferably within India)?
    Great article, btw — can't wait to try this out (once I source the chips, that is).

    • Thank you Subroto, I have swapped the positions of the diagrams as per your suggestion.

      In Mumbai all these chips could be easily procured from Lamington Road (in Grant Road)

      Thanks very much!

    • Congrats Avijeet on your success with the above project. Yes pin#13 needs to be connected to ground, I'll try to correct it as soon as possible.

      I had to delete your previous comment since i had some links, although I know those were intended for a generous cause by you.

  8. Dear Swagatam
    First of all thanks for an awesome blog that is helping all novice and experts!!!
    I wish to have a remote for 40 switches (lights) in my office!!! Today there are individual switches on a switch board. Will this circuit work for my purpose of controlling the lights individually?? Please help as this will help in controlling the lights sitting at on place!!!
    Thanks in advance
    Abhishek

    • Dear Abhi,

      yes surely the above modules could be used for controlling lights and other electrical appliances remotely.

      You would require 10 such Rx, Tx sets for the intended 40 lights.

      Each handset would allow you to control 4 lights individually, however managing 10 remote handsets and remembering their designations could become quite a headache.

  9. Dear Swagatam,
    Great information, Thanks. I'm looking for a RF control unit circuit I can make or buy. The RF remote control unit will be used to control a computer 12VDC or 5VDC fan to turn it ON/OFF and select Low/Med/High speeds, also need to be able to fire a 12VDC or 5VDC solenoid pin latch. Thanks for the help.

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