ATtiny Hacks: Look Ma, No Batteries!

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[Gadre] built his own ATtiny project without using any batteries. It’s an electronic Dice (or die if you’re being critical) which uses induction to charge a storage capacitor to act as the power source. The voltage generator is made from a tube of Perspex which houses a set of rare-earth magnets. At the enter of the tube [Gadre] machined a channel wich accepts about 1500 windings of 30 AWG magnet wire. When someone shakes the tube back and forth the magnet passes the wire, inducing a current.  The product is stored in a 4700 uF capacitor, which feeds a boost converter to power the rest of the circuit.

The ATtiny13V that controls the circuit is running its internal RC oscillator at 128 kHz, the lowest setting possible in order to minimize power consumption. After a good shake the user can press a button to roll the die, which is then displayed for several seconds on a group of seven LEDs. See for yourself in the video after the break.


30 thoughts on “ATtiny Hacks: Look Ma, No Batteries!

  1. I think a bare bones kind if dead bug design with a smaller supercapacitor (those 3 volt 1f ones should do the trick) would have made it a little smaller. Perhaps even using a peizo for something that you “roll” would also be cool.

  2. Don’t listen to people who say “it could be smaller” or whatever. This was an exploration, not a production piece. It was fantastic. I really like how the traditional “shake it up” motion for rolling dice was integrated into the object. Nice work!

  3. Pretty neat setup.

    I wonder though, how its lifespan is affected by the moving parts. I’ve gone through a couple linear induction flesh flashlights.

    If I were asked to make a shake activated, battery-less, die, I’d tear apart a $4 solar calculator and add a tilt sensor.

  4. Here’s an idea for digidice for your next round of roleplaying geekery. Look up how the SGI Lavarand system was built.

    Basically it pointed a crappy webcam at several lava lamps then periodically sampled a frame of video to use as a seed to run through some random number generation algorithms. Since the seed data was completely chaotic the whole system functioned as a true random number generator with absolutely unpredictable output.

    Instead of lava lamps, the camera could be aimed at any source of visual chaos, like a room full of RPG playing geeks and nerds. ;) For more chaos, add a microphone for additional random seed data.

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