I want to help some 5th grade students create a demonstration of how sine, sawtooth, and square waves sound and appear different. Ideally, we would have a simple 3-way switch, a speaker, and a simple oscilloscope to view the waveforms. This does not need to be a fancy synthesizer - simple is best.
I'm wondering whether anyone has recommendations on parts to buy, working code, and/or wiring diagrams (I already have an Arduino and can do code manipulation as needed if there's a good starter project out there).
While a PC or Ipad solution is the best, you could do worse than build one of these to show how the waveforms can be combined to make something more interesting, its also simple enough for kids to build themselves -
A few other noisey projects at the end of this page that might be interesting to kids -