Interfacing 433MHz RF Modules with 8051 Microcontroller

Hello Friends Today I am going to show you how to use a 433MHz RF module in your 8051 Projects. The 433MHz RF module is one of the cheapest ways of wireless communication other than IR that you can use in your 8051 projects.There is receiving and Transmitting module that we will needed. You can easily find them online for3-4$(150-200 Indian Rs).

Components required

  • Microcontroller (P89V51RD2) (2)

  • Resistor 10K (1)

  • Capacitor 33pF (2)

  • Capacitor 10uF (1)

  • 11.0592MHz Crystal (1)

  • 433MHz RF Transmitter (1)

  • 433MHz RF Receiver (1)

  • Buzzer(optional) (1)

Circuit Diagram and Description

RF Transmitter-receiver

[caption id="attachment_513" align="aligncenter" width="2116"]Receiving circuit Receiving circuit[/caption]

[caption id="attachment_514" align="aligncenter" width="1621"]Transmitting Circuit Transmitting Circuit[/caption]

Connections of the Transmitter Module

The smaller module of the two with a crystal on it is the Transmitter module. The Pin connections for the module are as below

Pin on Module            Connection

GND               GND on 8051 Board

DATA             P3.1 on 8051 Board

Vcc                  Vcc on 8051 Board

ANT                Connected to 17.25cm long wire

Connections for the Receiver Module

The Larger module of the two is the Receiver module.The Module has multiple GND and Vcc pins which need to be connected externally. The Pin connections for the module are as below

Pin on Module            Connection

GND              GND on 8051 Board

DATA            P3.0 on 8051 Board

Vcc                 Vcc on 8051 Board

ANT               Connected to 17.25cm long wire

About the Program

In this particular program, we are using UART to transmit 8-bit data over the RF module. The data pin of the transmit module is connected to the transmit pin of the 8051. When the Switch 4 is pressed on the 8051 Board then the ASCII value of character t is sent over the RFmodule.If this is received at the receiving 8051 then the Buzzer will turn on for 5 Seconds.


Click here to download the C, Assembly and Hex file.

This article is written by Aditya Wani.

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