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.

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37 comments

comments
December 23, 2011 at 2:31 AM delete

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

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December 23, 2011 at 11:15 AM delete

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.

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Anonymous
February 20, 2012 at 11:19 AM delete

hi
how can i connect load in the receiver circuit?

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February 20, 2012 at 12:26 PM delete

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

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April 10, 2012 at 12:37 PM delete

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

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April 10, 2012 at 12:44 PM delete

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.

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Anonymous
September 11, 2012 at 7:26 PM delete

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

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September 11, 2012 at 10:01 PM delete

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

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Anonymous
September 12, 2012 at 9:50 AM delete

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

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September 12, 2012 at 10:13 AM delete

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.

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Anonymous
December 18, 2012 at 11:00 PM delete

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...

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December 19, 2012 at 9:53 AM delete

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

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February 20, 2013 at 10:02 PM delete

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.

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February 21, 2013 at 12:17 PM delete

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

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February 22, 2013 at 11:02 PM delete

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..

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February 23, 2013 at 3:16 PM delete

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

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Anonymous
August 20, 2013 at 10:36 AM delete

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......

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August 20, 2013 at 8:04 PM delete

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

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March 6, 2014 at 4:10 PM delete

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

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March 7, 2014 at 9:57 AM delete

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.

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May 3, 2014 at 6:50 AM delete

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

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May 3, 2014 at 5:38 PM delete

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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May 4, 2014 at 5:13 AM delete

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

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May 4, 2014 at 12:59 PM delete

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

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August 14, 2014 at 9:21 AM delete

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..:)

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August 14, 2014 at 11:11 AM delete

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

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October 26, 2014 at 7:06 AM delete

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??

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October 26, 2014 at 1:05 PM delete

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.

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December 11, 2014 at 9:02 PM delete

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 :)

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December 12, 2014 at 10:34 AM delete

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...

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August 8, 2015 at 3:14 PM delete

Hi swagatam, nice tutorial on RF encoders and decoders.BTW, How HT12E/D can successfully communicate using 433 mhz rf modules did you know how they works? with PIC micro controller its very hard , maybe the working principle of these encoders or decoders is secret...

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August 8, 2015 at 8:24 PM delete

Thanks Mrunal, the internal circuitry could be extremely complex and intricate, so yes replicating these modules using PIC won't be easy, at least at our level.

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March 21, 2016 at 11:10 PM delete

swagatam ji i m using RF 434 receiver and transmitter.
i m using 16 inches radio antenna.
transmitter voltage 6 v
and receiver voltage 5 v DC.
range is 60 feets in home condition.

if i increase transmitter volt 9-12 volt
range not increase.
i need 500 feet range.
how can i got it.

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March 22, 2016 at 8:59 AM delete

Prashant ji, you can try increasing the antenna length a little more by using any ordinary flexible wire, may be around a 2 meter length, that's the only thing you can try....there's no other option to enhance the range....since it's rated with a range not more than 50 to 70 meters.

increasing voltage will not help

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March 24, 2016 at 2:51 PM delete

swagatam ji here is a problem
i m using RF 434 with ht 12 e and ht12d
i m using in home.
i have a door lock in in home woth help of car centeral lock remote.
here is problem if RF receiver is on car cennetal lock range getting to low.
if i switch off transmitter 434
then centetal lock range goes high.
please solution for it .

i m using in address ( no sjort with -ve to pin 12345678.

plz tell me if i change the adress with dip switch frequency change or data address change ?
thanx n happy holi.

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March 25, 2016 at 7:34 AM delete

prashant ji, yes matching the transmitter module's address connections with the receiver module's address connections will make them compatible with each other.....so you can try this through a SPDT switch.

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