IR data transfer is very often used in devices around us. Every TV, audio system, Air Conditioner uses IR remote controllers. Every device that receives IR commands have one simple IR receiver component inside it. It is usually covered with IR filter to reduce noise from daylight. This is not necessary when making IR remote control project with microcontroller.

Most of these receivers are very simple. We will assume you know basic concept of IR data transfer. You can read all about it that you might need in practice in Ultimate guide through IR Remote Control article.

IR receivers usually work on 5V operating voltage which is convenient for use with most microcontrollers. They demodulate received IR signal that come from your remote controller. Modulation is usually done on frequency of 36,38,40,42,44kHz.. If you use receiver that is specified for different frequency than remote controller you will still be able to receive commands. Band pas filter on input of IR receiver is not that much selective but sensitivity will be decreased. Band pass filter of one typical IR receiver is shown on picture below.

Block schematic of one such receiver is shown on picture below

You can determine for what frequency it is intended to operate by its marking. Usually it is included in component type name.

For example:

RPM7138 works best on ~38kHz

RPM7136 works best on ~36kHz..

These receivers have very small working current. Typically about 1mA.

Output pin of these receivers will give you TTL level digital output signal. Signal from RPM7138 when it receives connamd from Panasonic TV remote control is shown on picture below.

For details on specific model see its datasheet. Here I will give you two different IR receivers just to show you that there are not much differences between them

Here you can download datasheet for SFH5110

And here is datasheet for RPM7138 that is model used in Universal reception of IR code from remote with AVR article. IR receivers are small, low power, easy to find, cheap components that can give very attractive and interesting features to your projects. Here you can find example on hot to use them with microcontroller in Universal reception of IR code from remote with AVR article. Good luck!

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