The General Instrument AY-3-8910 is a sound chip that appeared in old home computers and game consoles. Vince Weaver has taken the chip and hooked it up to a Raspberry Pi and then added bar graphs and a matrix display for graphic feedback. He has worked out how to make the chip do most of the work, just as in days of olde and the result is chiptune heaven. Read how he did it here and see an example of playback below.