Thursday, November 11, 2010

My "akari"

Last Spring, after the Japanino came out, I started thinking about chopping up the Aurorarium and using the tricolor LED with the Japanino to make my own form of Aurorarium. In effect, the Aurorarium is like a modern lava lamp. It has moving shapes and patterns, since you draw on a mylar disk that is then rotated by a small motor in the base. The problems are, that 1 - the motor is noisy so you don't want this running at night when you're trying to sleep; and 2 - the patterns don't change, unless you have a bunch of mylar disks you want to mark up. However, if you connect the LEDs to the Japanino, you can create a much wider range of patterns as you switch combinations of LEDs one at one time, and you can put different lamp shades on them over time.

Shortly after I planned out my idea, the Edo Clock kit came out, and I wrote about my disappointment at learning that the next kit in the pipeline was going to be the Akari, which was going to take my idea to all new heights. But, a few weeks ago, I decided to chop up the Aurorarium anyway, just to free up some shelf space, and I connected up the tricolor LED to the Japanino to have something to play with. It's pretty easy to come up with pattern ideas. I used 3 basic ideas - random fade-ins; turning the LEDs full-on either with a binary counting pattern or Gray code, and manual levels selection.

The next step was to mount the lamp on a perf board. Once I got the through headers from Switch Science, I was able to get to work. I threw in 3 push button switches for pattern and level selection, and a photo cell to change brightness levels automatically when the room goes dark (my thought was that if you're trying to sleep with the lamp in the room, you want it to become dimmer with the lights off, and if the lights are on, you want the lamp brighter to be able to see it.)

For the shade, I wanted something small and simple. Small because I wanted to maximize the light coming out to make it look brighter; simple because what I really wanted was a "magic candle". Spark Fun sells a kit called the "magic candle", and the customer feedback is all negative because the LEDS flash full-on and off randomly in an irritating way. So, I wanted to make something that works better. I took the smoked plastic screen from the Aurorarium and cut a rectangle from it, wrapped it in a cylinder and held it together with sticky-back tape. The LEDs are held in place with a cleaned ice coffee sweeter syrup cup with the bottom cut out. The top is a piece of foil held by a slice from the neck of a plastic soda bottle.

Sure, the overall effect is pretty amateurish-looking, but the code running on the Japanino is fairly sophisticated, and I have 10 of my own patterns, plus whatever I decide to duplicate from Gakken's kits. Further, it dims when the lights are out, it's silent, and it works well as a strong candle. Best of all, the crinkled foil on top reflects the lights back at different angles, creating what looks like a "cracked wax" effect. I think it works out pretty well. On top of this, I can now connect up the Akari to the other 3 PWM pins of the Japanino and have two lamps running off the same sketch at the same time.

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