Re: Saab mic

Posted by czabel on
URL: http://bluesaab-forum.90.s1.nabble.com/Saab-mic-tp6p1472.html

If a mic swap is desired, it might be interesting to build a mic PCB to match the existing Saab mic setup, that way it's just -Unplug Saab mic -> plug in new mic, and you're off to the races. This would also allow us to add the RC circuit that the bare electret desires on that PCB instead of a new board rev. Keeping it in that nice little Saab box would certainly simplify the install for end users, and you'll already have to get in there to run new wires.

If we don't want to swap, and instead want to add a bias circuit to the mainboard, I'd be happy to try and
 help with that as well - I've got a decent amount of experience in Eagle, and really enjoy creating board layouts. It's also a tiny circuit and would work with 5V (I'm assuming there's 5V somewhere on this board?).

As for an electret to try out, give this one a shot: DigiKey Part Number 102-5628-ND. The datasheet supplies a circuit to use, where Vs will be MIC_BIAS. Set MIC_BIAS to the minimum value before connecting, and move up from there. It shouldn't be many steps before you hit the 500uA required for operation. Let us know how you do! If that doesn't work, the RN52 eval board has a more complicated circuit we could try.