From Friday, Jan 27 to Sunday, Jan 29 a few of my friends and I spent a lot of time at Artisan's Asylum in Somerville, MA. We weren't there just for fun (though we had plenty of fun). Instead we were there to design a working RC hovercraft in 48 hours. The participants from BUILDS (BU's hackerspace) were divided up into two teams:
Team McFly and the Hoverboard: Christopher Woodall (me), Ian Felder, Marc Beneck and Alejandro Bancalari
The Cult of the Devouring Fan and Brogle the Insatiable: Russel Shomberg, Patrick Ehrlicher, William Gullotta and Alex Whittemore
In the beginning we were given the electronics, a piece of pink foam, some wood and access to most of the tools in Artisan's Asylum. There is no real documentation from either my group's design, or the other BUILDS group's design; however we certainly had a ton of fun and we have pictures and videos. Also, it was my first time helping design a Radio Controlled vehicle and it was a ton of fun (which I hope to do again).
This is just a basic little dynamo which uses a tiny 6V DC motor I scavenged from an old CD drive. I have grander plans for the motor in the future, but I thought it would be cool to use it to turn on an LED with it!
The basic idea is pretty straight forward. If you take a motor, which has a permanent magnet in it, and turn the magnet on your own you will change the magnetic flux in the coil and as such start generating some current and, you will start to get a potential difference building up across the terminals of the motor. If I knew the RPM rating of the motor then I could figure out how fast to turn it to get a full 6 Volts. At the moment all I know is that I need to spin it pretty fast and the peak value my multimeter reads is 2.5 V, which is enough to power an LED.
Nomis is a Simon-like memory game for the ATTiny85, which uses the ATTiny85. The game logic in the ATTiny85 was implemented using AVR C and takes up 983 bytes in program memory and 6 bytes in data memory. The implementation size comes in under 1kB, but could most certainly be smaller. The pin usage, however, is very conservative and the games electronics take up a total of 4 of the 6 available pins. The 4 LEDs are controlled on 3 pins using Charlieplexing model (which could easily be extended to 6 LEDs). On the other hand the 4 pushbutton switches are feed into an ADC input through an R2R ladder configuration. I am very happy with the limited pin usage of this project.
The gameplay of Nomis is the same basic scheme as Simon. Which is to say once you initiate a game with it the game logic generates a random move, which lights up one of the 4 LEDs. Then Nomis waits for you to copy it. Each consecutive move is stored in an array and the string of moves must be copied exactly by the player. The game has no real ending conditions; however, the maximum number of moves is 100, but even then that limit was arbitrarily set by me. With a sufficiently large slice of memory and an extremely skilled (or cheat prone) individual the game could last forever. That said, the goal of the game is to best your previous score, which you keep track of by yourself.