Jar Of Fireflies

[Randomskk] has been attempting to make electronic fireflies for quite some time and finally settled on a design he liked. His jar of fireflies uses an ATtiny13 to control a set of 12 matrixed LEDs. The green SMD LEDs are each soldered to a pair of thin wires that hang down into the jar. The software picks an LED at random to flash and then flashes it 1-3 times. The random seed is incremented each time the jar is turned on, so you’ll get 255 different patterns. The power is just a standard coin cell. The project is fairly simple electrically, but the LED soldering could prove difficult. It was inspired by this firefly jar project. Check out [Alex]’s synchronizing fireflies too. A video of the jar is available below.


14 thoughts on “Jar Of Fireflies

  1. I feel this [blog entry] is a total pile of crap. Granted you acknowledge the original idea on instructables; but why not feature the original (and far better) jar of fireflies, and say ‘this other guy did it too’ instead of saying ‘this guy built a version of this other guys idea’.

    Just my humble opinion.

  2. Yes, why wasn’t the first fireflies-in-a-jar projected presented instead of this?

    Also, this idea is begging for the addition of a solar cell & charging circuit extracted from a solar garden light – fireflies that appear every night without the need to replace batteries.

  3. It could definitely do with some thinner wire, but in the dark you can’t really see the wires anyway, so it does still work fairly well.

    A solar panel would be a nice addition too (I might pick up some small calculator ones and rig them up so they sit on top of the jar), but as it’s kept indoors I doubt it’d get much light. An outdoors version with LEDs rigged to plants could really benefit from a medium sized panel hidden somewhere, though!

    frollard: the idea is the same, but the implementation is pretty different – the one at instructables has multiple songs and lights up a few at once, but takes ten times as much code (so needs an attiny45) and only controls six LEDs. I still think having 12 LEDs controlled by 5 pins and still having hardware PWM control of all of them is interesting, even if it is basically charlieplexing.

  4. If I recall from my days of catching fireflies in a jar, when one would light, they’d all light up, so you’d have an entire jar lighting.

    Fireflies exhibit the random lighting only when they’re out in the wild. Put them all together and they make a nice momentary lamp.

  5. Take a look at FireflyMagic.com/jar for the original “Fireflies in a Jar Kit”.

    They supply these devices to theme parks, zoos, nature centers, museums, and to stage productions, movies, and magicians.

    Their ‘Fireflies in a Jar’ were recently used in the Tennessee Williams play a Rose Tattoo at the National Theatre of London.

    They also have ‘Fireflies in a Jar” that operate on rechargeable batteries and have a solar panel on top of the jar for solar recharge.

    And, they even build battery powered units for Universities for use in the field to lure in real fireflies. Firefly Magic has been acknowledged in scientific papers for their work in this area, and for their patented technology that accurately recreates firefly flash patterns.

  6. I know I’m late to the party, but this post (as well as the Instructables post) inspired me to give this a go too. Admittedly, I used standard (large) LEDs but added some shrinkydink to make up for it ;)


    I also ‘hacked’ my fireflies to run off solar power after finding some dirt cheap solar-cells (with charging circuit) on allelectronics.com (http://www.allelectronics.com/make-a-store/item/SPL-07/SOLAR-CELL-W/CHARGING-CIRCUIT-1-RED-LED/-/1.html)


    Those solar cells should be pretty useful for a number of projects (I bought 4 to play with).

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