Here’s a fun project using the Audio Hacker shield for Arduino – a realtime audio reverser! This program records the audio input to the Audio Hacker’s memory but plays it back in reverse. The “play head” jumps ahead a bit, then plays recorded audio backwards, then jumps ahead to the next snippet, plays it backward, and so on. There is a bit of lag between the input signal and reversed output, but this is unavoidable: we have to record something before playing it backward. There’s no way to play something backward in perfect realtime. This audio snippets are about a half-second long, so the lag is pretty small.
It’s great to hook up to a TV signal and just reverse all the audio. Using this effect, spoken English sounds like Russian to me!
The example is in the Audio Hacker Library examples folder so you can load it into the Arduino IDE with
File->Examples->Audio Hacker->RealtimeReverser
As always, get the Audio Hacker library from GitHub: https://github.com/nootropicdesign/audio-hacker