It fits in a 50mm diameter gumball machine capsule.
Way low cost (about 1€ each if you make 10 of them).
It comes with a pre-programmed 28-second composition (which is kind of crazy).
The sound is generated by Pulse Width Modulation (PWM) from a wave table, so it can make complex, interesting sounds.
(If you feed the output into a recorder, the sound is way cool!)
Here is a video of the completed project (where you can here the nice sound, as well as the blinky-lights): http://www.flickr.com/photos/maltman23/50726767613/in/album-72157715852297553/
For high-res photos of the project (including wiring) please see: http://www.flickr.com/search/?user_id=67734410%40N00&sort=date-taken-desc&text=gumball%20sound%20capsule&view_all=1
The firmware is well-commented, so you can hack on it and make your own sounds.
I made this project because a local artist friend and I bought a capsule gumball machine that fits 50mm diamter capsules. We are collecting tiny art from lots of local artists. The gumball machine will be in a cafe a half a block from my apartment. The machine takes 1€ coins -- turn the crank, and you get a random piece of tiny art in a capsule. It's not much money (with only 1€ for each piece of tiny art), but the artists will get half of the proceeds, and the other half pays for the machine and capsules. The Gumball Sound Capsule project is my contribution. since each Gumball Sound Capsule cost me 1€ each, so I won't make any money (but I'm OK with that).
This project is licensed under CC BY-SA 4.0 Creative Commons 4.0 Attribution and Share Alike