We know 433MHz RF Tx Rx module have the ability to transfer Data sequence wirelessly up to 100 meters. A simple wireless switch can be made easily with one push button input, and you might think, How to use 433MHz RF Transmitter and Receiver? in a circuit which have multiple switch input and output. Here is the solution. By using IC HT12E (Encoder) and IC HT12D (Decoder) we can achieve multiple input and output in 433MHz RF Transmitter and Receiver circuit.
FS1000A Module takes sequence binary input (Logic HIGH and LOW) and modulates it in Amplitude Shift Keying and propagates as RF signal. The reverse operation happens in 433MHz Receiver module and gives sequence binary output. When we introduce Encoder and Decoder we can increase the ability of these module and get multiple input and output.
433MHz ASK RF Tx RX Module Pinout
Check FS1000A 433MHz RF transmitter and receiver Brief Note for full details. Lets Jump into the Circuits.
Wireless Switch 433MHz ASK RF Transmitter Circuit
Wireless Switch 433MHz ASK RF Receiver Circuit
Here for the prototype purpose we used Four push button switch as input and Four LED as target output device, and our aim is to turn ON and OFF the LED wirelessly according to the pushbutton input, Required components for this circuit,
- FS1000A 433MHz ASK RF Transmitter and 433MHz Receiver Module.
- IC HT12E (18 Pin Dip)
- IC HT12D (18 Pin Dip)
- Four Pushbutton Switch
- Four LED (any color)
- Resistor 1MΩ, 51KΩ, 330Ω
- Power supply
Construction & Working
Transmitter and Receiver circuits are constructed separately and both Encoder and Decoder ICs Address lines are grounded and Addressed as 00000000, and in Encoder IC HT12E Transmission Enable (TE’) kept in Ground that is LOW because it is a active low pin. For internal Oscillator to produce 3KHz range of pulse signal it requires 1.1MΩ External Resistor, here we have used 1MΩ External Resistor and its works fine. For Decoder IC HT12D the External Resistor for Oscillator is 51KΩ.
AD8 to AD11, four pins in the Encoder IC connected with input push button switch, when the Switch is open it is considered as HIGH input and when the switch is pressed then it is considered as LOW input because the other end of switch is connected with Ground supply. you can Invert this by connecting diode in reverse then pushbutton switch to these Data input pin.
In Receiver circuit After ASK demodulation Sequence of data received by the Decoder IC in DIN pin and after Receiving the Sequence of data, this HT12D Decoder IC processes the signal through its internal circuit and identifies the address bits and the data bits. Then it compares the received address bits with its own set address to determine if the data is intended for it. If the address matches then the data is send to the output pins and LED start to Glow or OFF according to the Data Transmitter wirelessly.
Schematic of FS1000A ASK Transmitter and Receiver module