Does anyone know what the analog and digital I/O pins are rated at in terms of impedance or power? Of course, I wouldn’t send them anything over 5 volts, and if I know either their impedance or the wattage at which they’d blow, I can scale my inputs so as to not destroy anything.
In particular, I’m wondering if I need to worry about taking the output directly from this (AA-1D: Electronic Rainbow : Super Snooper Big Ear Audio Amplifier Kit : Electronic Kits & Projects) little audio kit. (It’s spec/assembly sheet is here: https://www.jameco.com/Jameco/Products/ProdDS/151204.PDF). I’d imagine it spits out around 3V maximum (AC!), but I need to know that it won’t blow the analog inputs as soon as I plug it in, as I would’ve wasted $100 for nothing. (I’m buying things by the 10s, as I’m building 8 identical objects and want a couple spares of everything in case something goes wrong.)
Also, how would I go about converting the AC to DC? Do I need to do that via components, or can I just perform some math at the software side of things? I don’t care if I lost the bottom half (negative voltage) of the waveform, so hopefully I can just deal with this AC in the code.
Anyway, I’m just trying to get a low-quality audio input into the board (I only need to take amplitude values, so the sound quality isn’t important at all). What’s the SIMPLEST circuit I can do this with? Daniel sent me here (http://www.reconnsworld.com/audio/electretamp.gif), but this doesn’t seem to be working, even after decoupling the RadioShack electrets I have. The 1Mohm pot in that circuit also doesn’t make a 3rd connection; what gives? I suppose it’s also possible I haven’t got the software right, but that leads to another problem…
In short, has anyone built a working audio input circuit and patch that they can share with me? I need both the schematic/image of the circuit and the proper code, as it’s impossible for one to know if one’s hardware, software, or both aren’t right when something’s not working; one has to be 100% on either one’s circuit or one’s code to know that the other is wrong.
Thanks in advance.