Interface RF With ARM7

Introduction

Radiofrequency module is an electronic device used to transmit and receive radio signals between two devices.

  • Wireless communication is accomplished through Radio Frequency (RF).
  • Several carrier frequencies are commonly used in commercially-available RF modules they are 433.92 MHz, 315 MHz, 868 MHz, 915 MHz, and 2400 MHz.
  • By increasing the transmitter power, a large communication distance will be achieved.
  • The performance of the overall system may be improved by using matched antennas at each end of the communication link.
  • RF Module consists of two parts
    1. Transmitter section.
    2. Receiver section.

Transmitter

  • An RF transmitter module is capable of transmitting a radio wave and modulating that wave to carry data.
  • Transmitter modules connected with a microcontroller which will provide data to the module which can be transmitted.

Receiver

  • An RF receiver receives the modulated RF signal and demodulates it.
  • There are two types of RF receiver module
    1. Superheterodyne.
    2. Super-regenerative.

SuperHeterodyne

Super-Heterodyne module is generally imprecise as their frequency of operation varies considerably with temperature and power supply voltage.

Super Regenerative

Super-regenerative module is usually low cost and low power design using a series of amplifiers to extract modulated data from a carrier wave.

Application

  • Robot remote control.
  • Wireless data transmissions.
  • Alarm systems.
  • Digital home automation.
  • Industrial data acquisition system.

Hardware Required

  • Rf Module.
  • LPC21XX MicroController.

RF PinOut

Rf Receiver

  • Vcc=+5v.
  • Data=To Microcontroller pin.
  • Gnd=Gnd.

Rf Transmitter

  • Vcc=+5v.
  • Data1=To Microcontroller pin.
  • Data2=To Microcontroller pin.
  • Gnd=Gnd.

Transmitter Circuit

Receiver Circuit