LED Fireflies in a Jar

An ATtiny13 uses PWM to fade 12 0603 surface mount green LEDs in and out, suspended from the PCB inside a jam jar.

The ATtiny13 picks a random LED to flash each time, flashes it once, twice or three times randomly, then waits a random amount of time before flashing the next one. An incrementing counter is stored in EEPROM and used to seed the random number generator, leading to a different sequence each time the device is powered up via the switch mounted on the top.

The LEDs are arranged in a standard 3x2 matrix which gives 6 LEDs, and for each position there is a second LED in reverse. The two column controllers are PB0 and PB1 as they can do PWM - another two LEDs could be added between PB0 and PB1 (and were on the prototype) but made the PCB design needlessly more complex: 12 is more than enough!

See photos on flickr here: http://flickr.com/photos/randomskk/sets/72157608158262467/

Inspired by: http://www.instructables.com/id/Jar-of-Fireflies/

More info / source files:
http://negativeacknowledge.com/2008/10/18/led-fireflies-in-a-jarled-fireflies...

Category:

Science & Technology

Tags:

• DIY
• electronics
• fireflies
• leds
• attiny13
• attiny
• avr

[suikerpotje9481]

booooring



[visualtim]

That's really neat. The colours seem spot on, too.

[Yulami]

any guys have a cam? i have mine in my profile

meh hehe 5w