2011-01-20
The electronic shot timer CED7000 is widely used in IPSC and other practical shooting sports. It can be fitted with a 434 MHz (in Europe) radio frequency transmitter that will transmit timing information to external devices like big screens and remote viewing devices. These devices are sold by the manufacturer, and there seems to be no information on how to extract the information to other devices.
This is what I have found out about the protocol so far:
I am receiving the data with a radio device that can be tuned to that channel. I hope to be able to decode the data soon with a computer sound card input. I will be using Linux for that. Hopefully this timer input could be integrated with some scoring software.
This is the waveform as recorded in linux line input.
The main cycle seems to be 400 Hz ie. 0.0025 s. Maybe some kind of PSK?
There is another higher frequency beat there, maybe some kind of sync?
This is the raw file: recorded-1.93s-first-shot.raw (44100 Hz 16 bit signed raw file) and this is the wav: recorded-1.93s-first-shot.wav