The Code Project - Pocket PC TV Remote Control - Mobile / Embedded

The Code Project - Pocket PC TV Remote Control - Mobile / Embedded:

I recently lost the TV remote for my old Sony TV. In itself that was no problem, as I bought a replacement remote which did the job. However, when the TV lost its colour setting, I had a problem as it could only show pictures in black and white, and the replacement remote didn't have the buttons for colour adjustment. I decided to write a program on my old Jornada 525 Pocket PC to send the correct codes to the TV using the IR port.

There appears to be three main protocols for sending IR codes to devices. Sony uses the 'Pulse Coded' method which entails sending a steam of data containing header bits, '1' bits and '0' bits separated by spaces. These bits modulate a carrier of 40KHz, and are of different lengths, 2200 us for the header, 110 us for a 1 bit and 550 us for a 0 bit. The spaces are 550 us of silence. Most Sony equipment uses 12 bits of data, which is separated into 6 bits of address (the device type) and 6 bits of command. So the data looks like this: hxxxxxxyyyyyy where h is the header bit, xxxxxx is the 6 bits of the command (msb first) and yyyyyy is the 6 bits of address. I won't go into any further details on this, as there are many sources on the internet that describe the protocol and list the codes for the different devices. Some newer Sony equipment use 19 bit codes, and I believe that other manufacturers use the same format that I have described. It should also be possible to write similar classes for devices that use 'Space Coded' or 'Shift Coded' protocols.

I have written a class called CIrPulse using Embedded C , which encapsulates the functionality to control Sony and compatible devices from a Jornada 525 PC running Windows CE 3.0. It should work with other devices and Operating Systems, but you will need to try it!