Simply Sound

Task

The given task was to modify one of those sound recorders used in greeting cards by changing the resistor.


Work

Before altering anything I recorded the first few seconds of "Thunderstruck" by AC/DC to test if everything is working fine, check the quality of the replay – not that good, obviously – and avoid hearing my own voice. Subsequently I removed the original resistor and replaced it with a light depending resistor.

Sound-recorder-hack.jpg

After this modification the recording was influenced by the surrounding light; the more light was caught by the resistor, the more rapidly the audio signals were processed, thus making the pitch level higher.