In the context of a speech-to-text/IoT project, I needed to capture the audio output of one device and feed it to the mic of my raspberry PI. This gist is stricly concerned with the hardware aspect. Since I wanted to capture speech, not music, I used only one channel of the stereo audio
- One 1 microfaraday capacitor
- One 1 kilo ohm potentiometer
- Two TSR audio jacks
Circuit:
Right (or left) channel of TSR jack hooked to lug 2 of potentiometer (middle lug - the wiper).
Output of pot comes through lug 3 (rightmost when facing the lugs).
Nothing on lug 1 (used as ground when pot is used as a voltage divider - but we're only using it as a variable resistor here).
Output of pot connected to positive end of capacitor
Negative end of capacitor joined to both channels of other TSR jack (the mic jack) via a fork.
Of course, the grounds of the two TSR jack are connected.
Adjust the potentiometer to your convenience. To avoid damaging your mic input, you might want to add a resistor in series with the pot to ensure minimum resistance.
//TODO: Draw circuit diagram