The RC5 code uses the bifase modulation technic which means that every bit consists of 2 parts which are never the same. |
So a bit is always a high/low or a low/high transisition. By the RC5 code a 1 is a low high transisition |
and a 0 is high low transisition. For all the bits the most significant bit is transmitted first. |
Remember also that the outputsignal of the integrated receivers is inverted: |
Detecting an IR signal the output of the integrated receiver will be 0V. |
The duration time of each bit is equal to 1,778 ms, and the total time of a full rc5 code is 24,778 ms. |
The space between two transmitted codes is 50 bit times or 88,889ms. |
To improve noise rejection the pulses are modulated at a carrier frequence |
The carrier frequency of the rc5 code is 36 kHz so take always a receiver with a response |
frequency of 36 kHz. |
There are plenty of Detectors for receiving the bitstream of an IR remote control but the best |
I ever used is the TSOP1836 of VISHAY. (Datasheet available on my site). |
The TSOP1836 is a 3 pin device that receives
the infrared bursts and gives out the demodulated bitstream at the output. The RC5 code is an easy protocol to decode with a pic mircrocontroller . I will show an example to control your PC when it's finished |
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