i want to read the audio signal from my smartphone. Can i just cut a headphonewire and connect it to the analog in? (Arduino uno) I sadly dont know much about electronics.



1 Answer 1


No. It partly depends on the phone, but most put out a low voltage AC signal. This would drive the Arduino inputs negative. You can do this by biassing the input at the mid point (+2.5V) and feeding audio in via a capacitor. There are many projects which use similar to record audio.

PS I would not recommend cutting a headphone cord. The wires are very fine, and almost impossible to solder. If you want to do this make a custom cable.

  • What do you mean with "This would drive the Arduino inputs negative"? (Sorry not native english)
    – gorilla
    Commented Jan 17, 2015 at 15:12
  • @gorilla: signal transmission in electronic systems usually use voltage as the thing transporting the information. Usually the voltage is generated and measured relatively to a potential called ground, which often is also connected to casings and earthing facilities. AC signals which are always used to drive speakers reach negative voltages relatively to ground in (roughly) 50% of the time. The ardino has only inputs capable of measuring and detecting positive voltage levels. Milliways refers to the trickery needed to "convert" AC signals to readable signals on the arduino.
    – Ariser
    Commented Jan 17, 2015 at 19:22

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