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How to Wire Happ Trackball to Mini-Pac?
benarcade:
Thanks, Scott! I wired it up and it works. Here's how I wired it.
Both X and Y axis PCBs share a Ground and 5vdc.
benarcade:
One last clarification - I did actually hook up the big, green static ground wire to my PC chassis, but I'd rather not do that for the finished product.
Is there any danger of just grounding it to one of the MiniPac grounds? Wouldn't that ground via the USB then? I'd rather do it that way than have a separate ground wire from the controller to the PC.
BTW - I've read several accounts of 1) Green ground (static wire) isn't grounded at all, and it's no problem 2) It's grounded to a spare ground on the interface board (MiniPac), and it's no problem.
Of course, the best ground would be the PC chassis (or Earth), but I'd rather not do that.
PL1:
The green frame ground wire is there to bleed off the static electricity charge when you first touch the mounting plate and any charge that builds up when you use the trackball.
If you don't ground that wire (usually to AC line ground or the PC power supply metal case), static charges can zap the encoder as described in this thread.
Per RandyT, Static charges also attract dust/dirt which can collect on the rollers and eventually affect performance.
I'm not saying you can't ground it to the Mini-Pac, but the traces of an encoder are far more succeptible to damage and possible latent defects caused by ESD than the case of your power supply. ::)
Scott