One tool that I’ve been missing at my lab at home is function generator. They tend to be a bit expensive, so I haven’t bought one. I thought this might be a good opportunity to try and make one myself. I found a pretty common DDS (direct digital synthesis) chip, called AD9833. Then just strap a USB-enabled AVR micro there and maybe some analog electronics.
This board doesn’t do any of the special analog magic to allow for variable amplitude or offset for the signal. The output is fixed to 0-4v. I’m planning to make another completely analog board for adjusting amplitude and offset. [Link]