Week 8 - Analysis about RF module

RADIO FREQUENCY 

To control the wheelchair, we have decided to use the remote control. We have used the RF Module because it's easy on the adoption and the price is cheap. We've bought in Jalan Pasar. For those who dont know what is RF Module, i will explain it in below 

An RF Module is a small electronic circuit which is used to receive, transmit or transceive radio waves on one of a number of carrier frequencies. RF Modules are often used in consumer applications including wireless alarm systems, garage door openers, industrial remote controls, wireless home automation systems and smart sensor applications. Due to RF modules not requiring line-of-sight operation, they are often used instead of infrared remote controls. A module is a self-contained component of a system, which has a well defined interface to the other components. An RF module is a functional integration of semiconductor devices.

The RF module, as the name suggests, operates at Radio Frequency. The corresponding frequency range varies between 30 kHz & 300 GHz. In this RF system, the digital data is represented as variations in the amplitude of carrier wave. This kind of modulation is known as Amplitude Shift Keying (ASK).

Transmission through RF is better than IR (infrared) because of many reasons. Firstly, signals through RF can travel through larger distances making it suitable for long range applications. Also, while IR mostly operates in line-of-sight mode, RF signals can travel even when there is an obstruction between transmitter & receiver. Next, RF transmission is more strong and reliable than IR transmission. RF communication uses a specific frequency unlike IR signals which are affected by other IR emitting sources.

This RF module comprises of an RF Transmitter and an RF Receiver. The transmitter/receiver (Tx/Rx) pair operates at a frequency of 434 MHz. An RF transmitter receives serial data and transmits it wirelessly through RF through its antenna connected at pin4. The transmission occurs at the rate of 1Kbps - 10Kbps.The transmitted data is received by an RF receiver operating at the same frequency as that of the transmitter.

The RF module is often used alongwith a pair of encoder/decoder. The encoder is used for encoding parallel data for transmission feed while reception is decoded by a decoder. HT12E-HT12D, HT640-HT648, etc. are some commonly used encoder/decoder pair ICs.

Pin Diagram;