Well, I'm an Electrical Engineering undergrad at Georgia Tech, so I'd certainly hope I'm able to figure this out.
I haven't been able to find any negative voltage regulators that would accept a positive voltage as input; the only ones I can find (specifically the 7905) require a negative voltage input also. Unless, of course, I'm reading the datasheet incorrectly, but I don't think I am.
One hack (which is working for me at the moment, but it's rather ugly) is to use 4 AAA batteries in series to produce approximately -5V (technically 6) but that takes up more space than I'd hope.
I've been tossing around an idea in my head of using two 7805s to turn a single +12V into +5, GND, and -5 (GND would actually be at +5 volts if you use the +12V input as reference); however, I don't think it would work. The GND output would be the output of a 7805, which, if I'm not mistaken, can't "accept" current as GND needs to in this case. I might just put it together and see if it works, though -- just gotta dig up some 7805s.
Thanks for the help! |