There's prior art on that one... (using the microphone input as a ADC, sending power to the preamp via the headphone output) http://web.eecs.umich.edu/~prabal/

There's prior art on that one... (using the microphone input as a ADC, sending power to the preamp via the headphone output) http://web.eecs.umich.edu/~prabal/projects/hijack/ http://web.eecs.umich.edu/~prabal/projects/hijack/