As you may already know, the Xpand X101 use an infrared encoded communication.
I don't have access to an Xpand emitter,so I needed to record the Infrared pulses on an Xpand equipped cinema. I cant bring my oscilloscope to the cinema so I build a circuit that measure the pulse timings and send them on an MP3 audio recorder using the serial output of an Atmega8 microcontroller :
![Image](http://www.mtbs3d.com/gallery/albums/userpics/24608/thumb_ir_recorder.jpg)
To read the data, I just have to plug the PC serial port on the comparator output and play the recorded MP3.
The IR pulses can be interpreted as binary code :
The code that activate the glasses isn't send at every frame. It is send periodically, always after a Ron-Loff command. I don't know the original frequency but it's not important as the glasses only need it once to activate after a communication loss.
I personally send the code every 100ms to get a fast recovery after a communication loss.
I've also made a program to find the code by brute force it (try every combination) but my pair of X101 seems to activate whatever the code so it was not very useful.