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Sometimes, the back door is just easier - Jason Lindquist
Idle ramblings of an idle mind
jlindquist
jlindquist
Sometimes, the back door is just easier
One of my long-running backburner projects is a decoder for our scoreboard controllers at the high school. If I had something that could read the output, then spit it out a serial port, I'd have a way to put live game status up on the web. Or integrate timing data with the scorekeeping software I'm also forever developing. Or build my own mini-displays for the rooms our teams retire to at halftime. Possibilities, you know?

There's two things that have to happen to make this possible. I need to electrically decode the control signal (reliably pick out the 1's and 0's off the wire.) Then I have to decode the payload (what do those bits actually mean?) The second part is unreliable at best without the first part, and the first part meant beating up on microcontroller code for a while, and verifying the results by comparing them to a visual inspection of the oscilloscope trace. Ugh. Tedious.

Until now. I finally got hold of a wireless Daktronics controller. Cracked it open, and lo, an off-the-shelf 2.4GHz data radio stares out at me. (It's a Laird/Aerocomm AC4424-200, if you care.) They're about $90 each. Or you can buy a dev kit with TWO of them, with power and RS-232 level conversion, for a hair over twice the price. Knowing that the wireless payload is exactly the same as the wired data payload (it has to be--they sell upgrade/retrofit receivers for scoreboards, and the scoreboard internals are (mostly) not field-upgradable,) I can now plug this dev kit into a laptop, and the first problem is solved. Then I capture some data, write a script to post-process it and pick out patterns, and that's the second problem. THEN I can go back and design my own hardware for decoding the wire signal, because I can compare my own decoded payloads to the captured wireless payloads.
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