In this article, I will show you how to make a 433mhz rf transmitter and receiver circuit. There are variety of electronics projects with different purpose but wireless projects still stand different and attractive.
In this project I am going to use 433mhz rf transmitter and receiver circuit module. This module is cheap and easy to understand. The pin configuration of this module is widely available and its application is super easy.
Here I will show you the basic application of RF module by transmitting and receiving 4 bit data to control LED’s wirelessly.
The components required to make rf transmitter and receiver circuit are –
- 433mhz rf transmitter and receiver circuit module
- Encoder IC ( HT12E )
- Decoder IC ( HT12D )
- 18 pin IC base x 2
- Momentary push button x 4
- LED’s x 5
- Resistors – 1 MΩ, 33 KΩ, 470 Ω
- IC 7805 x 2
- 9V battery x 2
- Battery connector x 2
- Bread board
- Vero board
433MHz RF transmitter and receiver Module
This module comes in two parts, the first one is transmitter ( Tx ) part and the other is Receiver ( Rx ) part. The RF ( radio frequency ) module always works in pair to transmit and receive data. The transmitter module transmit the encoded data and the receiver module receives it. So the data can only be sent from one end to other end. We cant get any feedback from receiver side.
The transmitter module has 4 pins namely
+ 5v power supply
Receives data from
-ve power supply
The voltage range of Vcc pin is 3v to 12v. the current range of transmitter is 10 mA to 40 mA. The data transfer speed is 10 kb/sec and the frequency is 433 MHz. The name of the pins are printed on the module.
The receiver module has eight pins. Two pins for Vcc, three pins for ground, two pins for data and one for antenna. The pins can be identified by their names printed on the module itself.
Here Vcc pin requires 5v +ve supply. The operating current range is less than 6 mA. receiving signal frequency is 433 MHz in air. The received signal is supplied to decoder IC for demodulation.
HT12E Encoder and HT12D Decoder IC
The RF transmitter and receiver can work well without this IC. We can simply apply signal to transmitter’s data terminal and receive it from receiver data terminal. The problem in doing this is we can transmit and receive only one bit data. One bit data is not useful enough in practical applications.
When we use these HT12E Encoder and HT12D Decoder IC. We can transmit and receive up to 4 bit of data. These IC’s have 4 bit input that means we can make 2n = 24 = 16 different combinations.
Both of these IC have 18 pins and a operating voltage range of 3v to 12v.
RF Transmitter and Receiver Circuit Diagram
RF Transmitter and Receiver Circuit is shown separately is the pictures below –
To test the working of circuit I first made it on breadboard. The circuit worked well. The working of circuit is shown in the video below-
In the video you can clearly see that on the transmitter side we have encoder IC and on the receiver side we have decoder IC. IC 7805 supply 5v power to both encoder IC and transmitter module. 9v battery is the main power source that is applied to input terminals of 7805 IC.
The pin configuration / connection of encoder IC is as follows
Pin number 1 to 9 and pin 14 is connected to negative terminal of power supply. Pin number 10 to 13 is connected to push switch. 1 MΩ resistor is connected to pin 15 & 16. Pin 17 is encoded data output and pin 18 is positive power supply.
The pin configuration / connection of decoder IC is as follows
Pin number 1 to 9 is connected to negative terminal of power supply. Pin number 10 to 13 is connected to LED’s that show output. Pin number 14 is data input pin. 33 KΩ resistor is connected to pin 15 & 16. Pin 17 is connected to LED that will glow only when transmitter is in range. Again pin 18 is positive power supply.
Working of RF Transmitter and Receiver Circuit
In simple words, four push buttons creates a digital signal that is encoded by the IC. The encoded signal is then provided to transmitter module for its transmission in air.
The receiver module on the receiver side receives the signal from air and transfers it to decoder IC for decoding data. Now the decoded data glows the respective LED’s connected to pins 10, 11, 12, 13.
I finally designed this circuit on the vero board. It looks beautiful and perfect as shown in the pictures below
The working of circuit on vero board is shown in the video below –
Applications of RF Transmitter and Receiver Circuit
The applications of RF transmitter and receiver circuit are –
- Remote control toys
- Wireless network of small range
- Wireless security system
- Door bells
- Small range data transmission
- Remote control of household appliances
- Used in various IOT devices
Frequently Asked Questions
- What if all four or multiple buttons is pressed at once ?
- If multiple buttons are pressed at a same time, all the respective LED’s on the receiver side glow. Suppose if you pressed first three buttons at once, then the first three LED’s will glow.
- What is the range of this module ?
- This circuit can work up to 50 metres when a 15 cm long antenna is attached to both ends.
Discover More –
Suggested sites for buying components
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