In this post we start exploring the world of Wireless Communication and start with one of the simplest RF modules available for beginners, RF Modules working on 434 Mhz and using Amplitude Shift Keying (ASK) modulation.
In today’s generation, it is often required to switch electrical appliances from a distance without being a direct line of sight between the transmitter and receiver. As you may well know, a RF based wireless remote control system (RF Transmitter & RF Receiver) can be used to control an output load from a remote place.
RF transmitter, as the name suggests, uses radio frequency to send the signals at a particular frequency and a baud rate.
The RF receiver can receive these signals only if it is configured for the pre-defined signal/data pattern.
An ideal solution for this application is provided by compact transmitter and receiver modules, which operate at a frequency of 434 MHz and are available ready-made. This can be used to make wireless remote control systems which are cheap and handy.
Wireless Remote RF Transmitter
This simple RF transmitter, consisting of a 434 MHz license-exempt Transmitter module and an encoder IC , was designed to remotely switch simple appliances on and off.
The RF part consists of a standard 434 MHz transmitter module, which works at a frequency of 433.92 MHz and has a range of about 100 m (10 m- 20 m practically) according to the manufacture. The transmitter module has three pins (Data, Vcc, Gnd) for data and supply.
Note that, for the transmission of a unique signal, an Encoder is crucial. For this, we have used the renowned encoder IC HT12E from Holtek. HT12E is capable of encoding information which consists of N address bits and 12N data bits. Each address/ data input can be set to one of the two logic states.
The programmed addresses/data are transmitted together with the header bits via an RF transmission medium upon receipt of a trigger signal. To keep matters simple, we have grounded the address bits in the video/schematic.
Recommended antenna length is 17 cm for 433.92 MHz, and a stiff wire can be used as the antenna.
Wireless Remote RF Receiver
This circuit complements the RF transmitter built around the small 434 MHz transmitter module. The receiver picks up the transmitted signals using the 434 Mhz receiver module. This integrated RF receiver module has been tuned to a frequency of 433.92 MHz, exactly same as for the RF transmitter.
434MHz receiver module
The receiver module has four pins. Apart from a “ground (GND) ” and a “Vcc” pin, there are two pins for data output.
The “coded” signal transmitted by the transmitter is processed at the receiver side by the decoder IC HT12D from Holtek. HT12D is capable of decoding informations that consist of N bits of address and 12N bits of data. HT12D decoder IC receives serial addresses and data from the HT12D encoder that are transmitted by the RF transmitter module.
The “Valid Transmission” (VT) pin also goes high to indicate a valid transmission. A LED can be connected here to visualize a valid RF link.
The RF Receiver circuit can be powered from a standard 5V DC supply. Just as for the RF Transmitter, the aerial (17 cm for 433.92 MHz) has to be mounted as close as possible to the antenna of the 434 MHz RF receiver module.
Build a wireless remote using all the below components and make your first wireless project today.
1) 1 x RF Module Tx + Rx (434 Mhz) (Buy here)
2) 1 x HT 12E (Encoder) + HT 12D (Decoder) + Resistors (1M,50K) (Buy here)
3) 1 x General Purpose PCB (Buy here)
4) 2 x 7805 Based Power Supply Circuit Components (Buy here)
5) 4 x Switches (Buy here) + 5 x 5mm LED (Buy here)
6) Tools (Buy here)
NOTE : Use 2 x 100K resistors in parallel to get 50K value.
Assembled complete kit (Buy here)
Download Schematic from here.
Please follow the video for an easy step by step guide. In case of any questions or queries, feel free to post below.
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Im obliged for the blog article.Really thank you! Much obliged.
unable to find 50k resistor, is there any substitute
Please use 2 100K resistors in parallel.
circuit diagram send me bro
Check circuit here : http://blog.bm-es.com/wp-content/uploads/2017/01/RF-434-Mhz-Wireless-Circuit.pdf
What the use of this circuit.i
Mean for toys car plane flying bird etc.please reply I am B.Com.gratuate.but interest in electronic too.
This circuit is used to establish a simple 4 bit wireless communication. This can be integrated into wireless car, toys, boat, etc with some modification.
Your information about tranmitter and receiver is intresting and needed. So if you complite it with the circuit diagrams, it can be tried to practice it. Thank for what you have given.
The circuits are given in the links above.
if i add realy 5v its working
For driving a relay you need to add a transistor/driver.
You can however use a relay module which has all the circuit and use with the circuit directly.
Sir, Can I use the assembled circuit (available on ur ebay link) directly or I will have to modify it as per video ?
You can use the one on ebay and it works the same way.
In the transmitter section which is the data pin
In the transmitter section, the DATA pin of Transmitter is connected to the 17th pin of the Encoder IC.
How to increase it rang to 2 or 3 km
What module you prefer???
For 1km, we’ll recommend HC12 (Tutorial coming up), for more than 2km Zigbee High Range Transceivers are available.
U r amazing bro I’m going to subscribe u r chennel
Please send circuit diagram
You can download it from : http://blog.bm-es.com/wp-content/uploads/2017/01/RF-434-Mhz-Wireless-Circuit.pdf
What are the components we need send me clearly sir
Please check it in the blog, complete list is given already.
My link LED blinks, but LEDs at pin no. 10,11,12& 13 of HT12D constantly lights. It does not blinks over the signal of the switch at remote section. Please guide.
If Link LED is blinking on sending data via Transmitter that means data is being received.
Please check :
1) Antenna size and coiling is proper.
2) Power source is good.
There are two pins for out put data right…… For which pin shoud connect it???
Which pins are you mentioning?
If you are talking about the Data Outputs, you have to use the same pins which you have used in Transmitter Encoder IC.
I use a RF remot system in 20 channel remot,
But not series in use one bye one use
Plz take a idea or ckt diagaram make a ckt & remote
Use in 9 v or 5v
Your question is not clear.
Good day!! I do this project but the ranges of my RF transmitter and receiver is low. How can i expand it? Do you have a suggestion? The antenna I used has no cover. I strip the wire. Thank you for reply!!!
I forgot, I need to put the transmitter near the receiver to receive. The distance is 1 inch. Thank you again!!!
Use helical antenna for better range. We get about 5 – 10 mtrs range from this.
Thank you!!! In your video of RC car did you use helical antenna? Because that range is ok for me. May i know what type of antenna you used.
In the blog video we used a Single Core Wire of 15 – 20 mtrs length and coiled it to make an antenna. You can use this too.
Thank You!!! May i know what type of antenna you use in your RC car. Because that range is ok for me.
Can i have your email please… i want to send you my robos vedeo..i dont understand where the problem arises…. need your guidance plz… if posssible olzz mail on my id
Mail to [email protected]
How to convert in 8 CH ? Because currently is 4CH
Hello, you’ll have to refer to another encoder decoder based design.
Please you refer me which simple like your type.
I have bought a ready made circuit but it is not working
The link led is also not working and the data is also not being transmitted though they are getting a proper power supply
Please tell a solution
Hello, if you purchased from our store, we can fix it. Ship it back to our address or drop a mail with your product details. Mail to [email protected]
Your house is valueble for me. Thanks!…
Can you tell me that external ANT is required.
Hello, you need to add EXT ANT if you need better range.
If I buy those materials that u given in link then can I make that circuit
Hello, yes you can make the circuit.
Tell me how to modify it for dron
Hello, drone is a complicated thing and not possible only using this.
Excellent post however I was wanting to know if you could write a litte more on this topic? I’d be very grateful if you could elaborate a little bit more. Bless you!
Hi every one.
I have tried the Tx and Rx circuits i couldn’t able to succeed. Vt led has not gone high. Kindly help me out.
Thanks in advance
Hello, are you using the same components as posted by us?
Sir can you please make such video of transmitter receiver circuit with DPDT switch
Hello Ali, please check this : https://bm-es.com/2016/12/15/diy-wired-rc-remote-controlled-vehicle/
it’s 433 Mhz RF Module not 434 Mhz in your blog.
Yes, it means the same.
Hi bro ,
can you PLZ tell me which software did you use to draw the circuit diagram i need it for my school project .