As I have already told you when an interface used between transmitter and receiver in infrared (IR) then it is called IR remote control. In whole frequency spectrum infrared region just legs behinds visible spectrum and its frequency range is between 0.1-100 Tera Hz. Its wavelength is in terms of micrometer (µm)

In IR remotes IR LED is used in transmitters which emits IR light. In receivers any IR light detector can be used like photo diode, photo transistor etc. I have used IR sensor used in TV/VCD/Music systems as a IR detector because it's performance is best.

These remotes are advantageous because

Advantages:-

• Very chip. Cost of the components used is very less compare to RF remotes

• Easy to implement

• Small and handy because no need of bulky antennas as in the case of RF remotes

Also there are certain limitations of these remotes

 Disadvantages:-

• They have quite less range compare to RF remotes. Usually up to 10 meter

• Less directivity means you have to point the remote toward the sensor every time when you press a switch

• Line of sight is required means transmitter can not communicate with receiver if they are not in line of sight of each other

• IR light can not penetrate through big obstacles like wall, partition etc.

Because of these limitations these kind of remotes are usually used for general purpose applications like (as I told you earlier) to ON/OFF any AC/DC device in homes/offices/shops, fan regulator, remote bell etc. These kind of remotes are not used for specific applications in industries because of its limitations.   

I have develop seven different kind of IR Remotes. All of them have totally different design and they are used for different applications. They are given on left hand side bar. Please click on any project to see detail description, circuit/block diagram, schematic etc.