Thursday, December 22, 2011

RF Remote Control Encoder and Decoder Chip Pinouts Explained

Making your own universal remote control systems today is very easy. Such procure the relevant chips, assemble them and here goes, your hi-tech remote control device is working for you.
Here we explain a couple RF 433kHz remote control chips especially designed for the purpose. The IC TWS-434 along with its encoder chip HOLTEK’s HT-12E form a high class transmitter circuit, whereas the chip RWS-434 through its complementing decoder IC HT-12D operates as the receiver module. Both of the above modules are able to exchange 4-bits of discrete data for control four external loads separately.
With the easy availability of accurate remote control chips, making your own universal remote control modules is today just a matter of few hours. We discuss a couple of compact RF remote control transmitter and receiver modules here using the chips: HT-12E, HT-12D, TWS-434, RWS-434
Making a hi-end professional remote control system at home is a child’s play now. With the advent of micro remote control encoder and decoders chips, making a RF remote control is today a matter of a few hours or rather minutes. Applications of remote controls made from these chips are countless; you may use it for controlling practically any electrical gadget that you can think of, the best application being for car security systems.
A couple of RF remote control chips, the TWS-434 and the RWS-434 both complement each other, the first one being the transmitter and the later one the receiver.
The chip TWS-434 is basically a tiny 4-bit transmitter module, which is able to transmit 4 types of coded signals discretely, whereas the RWS-434 exactly compliments these signals by receiving them and generating 4 discrete decoded signals at its outputs.
However both the above primarily functions just as wireless sender and receiver and therefore require external encoders and decoders to be integrated for the said operations.

Understanding the Transmitter Module

A couple of HOLTEK’s encoder and decoder chips HT-12E and HT-12D work in conjunction with TWS-434 and RWS-434 respectively to produce the desired ideal universal remote control operating parameters.
Referring to the diagram alongside, we find a straightforward RF transmitter configuration using the chip TWS-434 and HT-12E.


The IC TWS-434 has in all 6 pin outs, 1 and 2 are the positive inputs, 3 and 4 are to be grounded, 6 receives the 4-bit encoded signals, pin 5 being the antenna for radiating the received signals.
The 4-bit encoding is done by the IC HT-12E. The wiring of this IC is also very simple; all its 1 to 9 pin-outs are shorted together to ground.
Pin 16 and 15 are coupled to each other through a 750 K resistor.
Pin-outs 10, 11, 12, 13, all receive 4 discrete data simply through the connections of the respective pins to ground via a push button switch.
Pin 14 confirms switching of the transmitter signals when connected to ground via another push button.
Pin 17 is the output and conveys the processed 4-bit ata to the IC TWS-434 for the final relay. Pin 18 is for the positive supply input

Understanding the Receiver Module


The diagram alongside shows a similar configuration to the above, but with exactly the opposite transits.
Here, the chip RWS-434,s antenna receive the data transmitted by the above transmitter module and sends it to the IC HT-12D for the necessary decoding of the 4-bit data which ultimately is decoded and produced at the respective outputs for driving the connected loads.
Understanding the pin-outs of the IC RSW-434 is pretty simple, pin 1, 6 and 7 are all shorted to ground.
Pin 4, 5 go to the positive supply.
Pin 2 outputs the received data to the decoder IC and pin 8 serves as the antenna.
The decoder chip HT-12D has its entire pin from 1 to 9 fixed to the ground potential.
Pin 15 is connected to 16 through a 33 K resistor as per its specs.
Pin 14 receives the information received by RSW-434 and after decoding the processed data is obtained from the pins 10, 11, 12, 13 respectively, which is further fed to the output driving circuit for activating the connected gadgets.
Both the modules of the above universal remote control work satisfactorily through a regulated 5 volt power supply unit.

31 comments:

  1. Hi swagtam

    i need your help remember you load circuit for over voltage and under voltage protection on Bright hub.
    can you tell me the part number for I wants to use The Ultimate High/Low Voltage Protector Circuit but i don't know what kind of part number to use for Transformer and for Relay. Part numbers from digikey.

    also i wants to use this ckt for a

    thanks

    ReplyDelete
  2. Hi Kristin,

    Welcome to my blog...

    The transformer is 0 - 12V, 500mA and the relay is 12 V, 400 Ohms, SPDT type.

    Thanks and Regards.

    ReplyDelete
  3. hi
    how can i connect load in the receiver circuit?

    ReplyDelete
    Replies
    1. By using a resistor, transistor and relay network at any one output of the decoder chip

      Delete
  4. hi,
    i made this ckt.
    but the ckt is not running ???

    ReplyDelete
    Replies
    1. Hi,

      The above circuits were taken from the manufacturers datasheet, you may check the following link to get more information about these chips:

      http://www.rentron.com/remote_control/remote1.htm

      Regards.

      Delete
  5. Hi ,so what does pressing the switches for pins 10,11,12,13 in the transmitter actually do and lets say to activate a transistor as a relay would you have to add anything? thx

    ReplyDelete
    Replies
    1. You'll have connect the flip flop to the relevant output of the second diagram as explained in the article.

      Delete
    2. but why cant you connect the base of the transistor directly to the output pins of the decoder ? and can the 4 pins be used as 4 switches for 4 different circuits? such that when you activate pin 10 on the encoder it provides and output in the pin 10 of the decoder and when you activate pin 11 on the decoder it provides output in pin 11 of the decoder and so on. thx a lot for your help

      Delete
    3. Yes you can connect via a limiting resistor, but the transistor and the subsequent relay will be ON as long as the Tx button remains depressed and will switch off when Tx buton is released...it will not flip/flop.

      The 4 decoder outputs correspond to the 4 encoder switches.

      Delete
  6. I am having problem with the circuit.I need to transmit 8-bit, so i used TPS12codec but no result can you tell me how to check the encoder/ decode. The TPS12CODEC can be configured as both encoder and decoder. pleae mail me a solution at...

    ReplyDelete
    Replies
    1. I am sorry I have no idea about it since I have never used it practically.

      Delete
  7. hello..i used the same ckt shown above..but am not gtng any result..i hav checkd all the connections..when i checkd the voltage at all the points,and i found that voltage at the address pins is not zero..instead m gtng a potential of 2.5 smthng..can u plz suggest me sugst wt might b the possible error.

    ReplyDelete
    Replies
    1. I have put everything as per the manufacturers datasheet, I have never used these personally.....

      Delete
  8. ok..i got that..but now the prblm is..im gtng a voltage of 2.04V at the data out pin of rws 434..even if i remove the transmission circuit..i.e. without any reception..reciever is showing a voltage at its data out pins..what cn b the possible reason..

    ReplyDelete
    Replies
    1. You can refer to the following site and the to the given links that's been included there, it might help.

      http://www.rentron.com/remote_control/tws-434.htm

      Delete
  9. hi i have seen rf tx'r contains 4 pins .. here u hav made tx'r 6 pin connection to encoder how is it possible. could you explain clearly......

    ReplyDelete
    Replies
    1. the outputs are four only, the extra pins are unused or are shorted.

      Delete
  10. Will it be secure what if another person would build the same circuit will that person be able to control the output What can i do to make more personalize like the remote for the car alarm. Can i used a dual tone multiple frequency encoder decoder with the transmitter

    ReplyDelete
    Replies
    1. The possibility can be eliminated by configuring the address pins uniquely for the particular Rx/Tx sets.
      Suppose you disconnect all the address pins A1 to A10 of the Rx module and select A1 and A2 only for the ground connections, and you do the same with the Tx module....this will make the two unit compatible and paired with each other uniquely and will not respond to other modules in the vicinity which could have a different address pin configuration.

      In this way you can select different sets of address pins and group them with each other or with ground (identically for both the modules) for creating unique pairs.

      Delete
  11. Hi, I'm making a similar circuit but I have a little problem I bought two pairs of the rf circuits, I mean 2 transmitter and 2 receiver in order to have 8 devices to controlled, but when I did the first circuits (receiver and transmitter) they worked properly, but when I did another pair of circuits (receiver and transmitter), the first circuits stop working, actually they work if I don't connect the second circuits and the second circuits work if I don't connect the first circuits, what could I do?, both circuits have a different address

    ReplyDelete
    Replies
    1. Hi, It's difficult to figure out, they might be operating with the same frequencies but in that case all should have worked randomly irrespective of whether remote#1 or remote#2 is being used, but in your case one is blocking the other, I have played with many such circuits but haven't faced this problem yet, so really can't troubleshoot the issue.

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    2. could I change the frequency? , both remotes are in 434Mhz frequency

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    3. yes, you can try doing it if you know how to it.

      Delete
  12. Dear sir..may I know which software did you use to make schematic circuit? I always use proteus..but some components are not available in that software..and I want to run a circuit simulation..please help me again..thank you and waiting for your reply soon..:)

    ReplyDelete
    Replies
    1. Dear Akmar, I usually simulate the circuits in my mind, I don't use any software, so not sure about them.

      Delete
  13. hy...according to your circuit in the receiver side,data pins (10-13) are having high voltage initially and get connects to ground wen push button is pressed..but my data pins are having low voltage(0.43V)initially..is there anything with the push button connection??

    ReplyDelete
    Replies
    1. hi, I can't see where I mentioned this??

      anyway, if the pins are low initially and become high on pressing the Tx buttons then it's fine too...you can configure the output stage accordingly.

      Delete
  14. Hi Sir.
    I am boy who has very keen interest in Electronics and Circuit making. Seeing this project of yours, I wish to try this out. But I had also seen another post in which the circuits contains few additional and different connections, while the basic components remains the same as of this circuit. So wanted to know whether you had tested out this circuits and checked the proper functioning of this circuit, assuring 100% working.
    This is the link to the other circuit--->>>
    http://homemadecircuitsandschematics.blogspot.in/2013/07/simple-100-meter-rf-module-remote.html

    Please Reply Soon
    Anxiously waiting to try out this project :)
    Thanks A Lot for sharing your hard works with all of Us :)

    ReplyDelete
    Replies
    1. Hi Jibin, the circuit has been tested by a few of the readers from this blog and they could successfully implement the results, these circuits have become very common and reliable nowadays and it's not at all difficult to work with these chips...

      Delete

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Readers are advised to proceed with the construction of the presented circuits only after understanding the concepts from the core. Not adhering to this can lead to failures and frustrations.