hello all, heres an attempt i made at something like an LED throwie..
the problem (for me) with led throwies is that they just consume their battery, and produce light.. but they could be better at doing both..
first you have to accept the premise that your willing to spend a bit more for the tradeoff..
the inspiration for this came from some of my other projects, and of course the "LED as a sensor" concept as well as the "LED throwie"
so the parts list:
1 common cathode, tri-color (RGB) LED
1 12f683 pic micro
1 coin cell battery holder
(cheap plug) http://www.makenyc.org/
Step 1: So Whats It Do?
the software is designed to use the LED as a light sensor (so as not to waste power during the day)
the led as an entropy source (to make each firefly unique moments after switching it on) to vary blink color, and rate.
and of course to play a flash pattern every so often in a way that seems "organic" and isnt just an "on/off" blink
and of course use as little power as possible!
(apologies for the darkness of the video, but the light had to be dim enough not to trip the fireflies daylight sensor)
Step 2: Pic Code and Assembly Instructions,
assembly is straight forward, the common cathod of your RGB led gets soldered to pin 2 of the pic, R-G-B pins get soldered to 7-6-5 and the pic power and ground go straight to the battery power and ground.
to put the whole thing together i just put the pic upside down on top of the battery casing, with a small dot of hot glue, bent the power and grond pins to reach over to the battery leads and attached the LED and hot glue a magnet and i was ready to go, total construction time was about 1.5 minutes.
Step 3: Suggestions
battery life is hard to estimate on this one, but... during the day the pic will consume ~25-30 microamps of current.. thats... microscopic.. at night, depending on the blink patterns generated.
sparkfun claims their coin cell has 250mAh of battery life, which, if the pic were the only thing on there would last well over a year, with the LEDs and of cours other factors like phantom drain from the battery..
i would estimate a couple weeks of random firefly like goodness..
some other ideas being thrown around are to maybe use infared to communicate between fireflies to some interesting effect.. but let me know what you think!