For a long time a had this idea that i wanted to try to control bent toys from a computer. Partly because i wanted to control bent instruments in ways that are difficult or impossible when playing them manually, and partly because i think it would look way cool to have a 1$ flea market toy hooked up to a computer.
My idea was to interface a toy to the parallel port of a computer. My first attempt involved a large metal box, an interface kit bought in an electronics shop, a homemade PCB with 8 relays on it, and a 12 V power supply to feed everything. I actually made it work, but it was very impractical, big, heavy, relying on mains power, and the relays was clicking in a very annoying way.
Then John Mahoney from the Benders group suggested that i checked the 4066 switch IC out. I did and after quite a few hours on the net, figuring out how to control it from the parallel port i found out that it was really very simple.
So now i have an interface that consists of nothing more than two 50 cent IC's, a small strip of vero board and a lot of wires. The only limitation is that it can only be used in toys that run at a maximum of 7.5 Volts, as this is the maximum voltage the 4066 IC's can switch.
Besides the actual interface, the system consists of a sequencer program written in Visual Basic,and a photocell for pitch control mounted in a plastic tube and placed in front of the computer monitor so the sequencer can control the amount of light reaching it, by changing the colour of a square area the photocell can "see" through the tube.