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ericbolo/attenuator-cable.md

Last active August 28, 2016 15:56
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Attenuator cable: stereo jack audio output to mono mic TSR jack.
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attenuator-cable.md

Introduction

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

Checklist

  • One 1 microfaraday capacitor
  • One 1 kilo ohm potentiometer
  • Two TSR audio jacks

Output attenuation

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

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