http://www.stormcam.org/mono-microphone/
What sort of conversion would you need to take a output from headphones (Stereo) to a Microphone input(mono)?
I don’t need to combine left and right audio (would be nice) but i know the speaker level signal is different from a mic input. In order for things to work correctly it needs to be a mic level input.
You can use 2 resistors to do this. Just do this twice if you want both right and left channels. Since you say it a headphone out, take about a 300 to 500 ohm resistor from each channel hot to ground. This loads the circuit with the equivalent of the headphones. Connect a 27,000 (27k) to 47,000 (47k) ohm resistor in series to feed the mic input. If using two of these for left and right the other end of the 33k to 47k resistors can be connected together and then fed into the mic input. As crude as it sounds, it works and is effective. I’ve done this several times in the past.
How to Change A Mono Microphone into a Stereo Microphone