July 18, 2012

IR Remote Control

What is IR Remote Control ?

IR or Infrared Remote control is referred to when any product or appliance is controlled with the help of a handset which emits Infrared light. This IR light is emitted in a particular pattern. The controlled product is having an IR sensor, which converts this light pattern into recognizable information. This information is used to control the product.

Now let us understand the whole process in little bit detail.

InfraRed radiation was first discovered in 1800 by astronomer William Herschel. As you know what we see as light is a visible part of light spectrum. InfraRed or popularly known as IR light is having higher frequency than normal red light. This IR light is beyond our eye’s recognizing limit. Because of this we can not see the IR light. You may be surprised to know that many of living bodies including our own body & non-living bodies also emit IR light. ( yes including tube light of your room & mighty SUN !)

Now let us see how IR remote functions. IR remote handset consists of an IR Light Emitting Diode (LED), a small IC ( Integrated Circuit) and usually 2 pencil cells – batteries and a keypad. When any button is pressed on the keypad, it is recognized by the ic and according to the pressed button, a special pattern of light is emitted with the help of IR LED. This pattern is also known as Code. This code is very well defined. It is a pattern of Light emission with some breaks in between. This pauses & emission are in microseconds ( a microsecond is one millionth of a second).

At the product end an IR receiver converts this pattern – code of light into proper information and used to control the product functions. Let us take a practical example. When you press a Volume+ button on your IR remote handset of TV, it emits a particular code through its IR LED which is located at the front end of your remote handset. An IR sensor in your TV ( generally positioned behind small dark colored glass window) receives this light and converts this signal into an information which is to increase volume. The circuit of the TV then increases the volume of TV.

IR remote control was popularized specially by major TV companies. They developed special codes to control their own TV sets. Most known codes are of Philips ( RC5) and that of SONY (SIRC) & NEC of Japan.

As these codes are now well known, you can use this technology to control your own equipment. For example we have IR Remote control Relay board with which you can control any electrical items of your home or office. Now, you know what is IR Remote Control. In my next post, I will show you how you can control lights & fans of your home or office with the help IR Remote handset.

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