Teaching the Raspberry Pi how to read analog inputs is easier than you think! The Pi does not include a hardware analog to digital converter, but a external ADC (such as the MCP3008
) can be used along with some bit banged SPI code in python to read external analog devies. Here is a short list of some analog inputs that could be used with this setup.
This guide uses a potentiometer to control the volume of a mp3 file being played, but the code can be used as the basis for any kind of analog-input project