glow bugs in a jar

Continuing my learning of electronics doodads, this week I have been introducing myself to the 555 timer and a display driver.

I’d rescued a load of the 555 chips out of some junked circuitboards, so when I saw this instructable for fireflies in a jar I thought I’d give it a go. (This page was also useful, as was this datasheet because I could only get a 4033 not a 4026 – pin 14 to ground people, pin 14 to ground.)

When the parts came the 1500uF capacitors were HUGE, so I thought I’d run with that rather than trying to make wires and parts invisible.

Here’s what I ended up with instead of fireflies:

Each glow bug is made out of - and only of - the components requred for that part of the circuit. All parts are functional.

Each glow bug is made out of - and only of - the components requred for that part of the circuit. All parts are functional.

After trawling some charity shops and finally finding a couple of glass jars, I squeezed in five bugs, the circuitry and some sand donated by a friend.

Making it really difficult to photograph in the process!

Battery and circuit embedded in the lid. Who wants a laser cutter? I want a laser cutter.

Battery and circuit embedded in the lid. Who wants a laser cutter? I want a laser cutter.

bugs2

bugs1

The capacitors are a nice way to get the LEDs to fade in and out. I’m using a 330 ohm resistor to get that fade time. (I’m also using a 220k resistor as R2 in the timer circuit to give an interval of about 14 seconds between changes.

Here’s some not great video that sort of shows the effect:

Untitled from nikkipugh on Vimeo.

Rest assured they’re pretty awesome when seen with your own eyes, ‘cos eyes are amazing.