IR or infrared communication is a common, inexpensive, and easy to use wireless communication technology. IR light is very similar to visible light, except that it has a slightly longer wavelength. This means IR is undetectable to the human eye - perfect for wireless communication.
Infrared communication was something that we needed, so the Koruza units could talk to each other. We all know that turning your TV with IR LED from a remote control is nothing special, but when you want to do that at the distance of 100 m than it is something worth mentioning.
We tested the system for long ranges with Arduinos and some additional hardware to get maximum out of the high power infrared emitting diode. Now, we are migrating all that to Raspberry Pi, and soon it would be ready for integration with the Koruza wireless optical system.
In the testing phase, we used two Arduinos, one for the IR transmitter and one for the receiver. Arduino with his output current from the controller can drive the IR LED, but there is not enough power to send the light signal far. To overcome that problem we used MOSFET and separate power source, but that was still not enough for the light to travel at least 100 m. We had to do something with the light rays. Collimating the beam of Infrared light was the solution. We did some calculation, put the collimating lens in front of the IR led, and that was it. We started testing it and make sure it works smoothly at the distances we needed.
Now we have working IR link for sending and receiving data over long distances. Because the current version of Koruza system has Raspberry Pi inside it was a logical move to migrate the system to RPi platform, so the link could be tested with Koruza units.