Firefly LED light wand! I want to make one.
June 23, 2016 11:00 PM   Subscribe

There is an LED toy that I want to recreate. It was the length of an umbrella, without the canopy, and looked like the person was being followed by a bobbing, waving band of fireflies. Details inside.

I can't find any companies that currently make them (they used to be about $100), or I would buy it. It is a single color-fade LED at the tip of each of a dozen or so 3' lengths of thin wire or metal tubing connected to a battery pack that serves as a handle. The wire/tubing is thin enough that it waves at the slightest movement, but doesn't flop over when still.

When asking some of the makers, they say piano wire can be used for this (is it all hollow? I need to run a wire down the inside). I have access to solder equipment, and can source whatever materials necessary. Any resources, advice, or suggestions are welcome.
posted by ananci to Technology (8 answers total) 2 users marked this as a favorite
Are you sure it was LEDs on wires and not Fibre Optic?
posted by missmagenta at 4:28 AM on June 24, 2016 [5 favorites]

Yeah it sounds like fiber optics. I was able to find something called fiberflies or fiberwhip - here's one.
posted by amanda at 7:11 AM on June 24, 2016

If you're still interested in building a larger scale one, you could use the piano wire as your ground and just wrap a thin-gauge power wire around the outside of the wire.

But it also looks like "Pixel Whip" and "Space Whip" are other names for the fiber optic version, and there are even a few of those available Amazon Prime.
posted by straw at 7:31 AM on June 24, 2016

I can't help you build this but I can inform you that piano wire, i.e. wire used for piano strings, is definitely not hollow.
posted by spielzebub at 8:52 AM on June 24, 2016

No, it is definitely not fiber optics :)

I am familiar with Pixel Whips, and had an opportunity to examine the firefly wand closely. It was very clearly small LEDs at the tips, like the kind used for throwies.

Straw's idea of wrapping a power wire around piano wire sounds correct, so I'm going to try that. They must have covered the power wire with something, so I'm thinking to use thin vinyl tubing or a paint-on rubber coating. Is using rubber paint a bad idea? I don't want to shock myself while I'm carrying it around.

Reading this forum leads me to believe that there are a lot of details that went in to making this thing, and I've never done anything electrical before, so any resources on how to hook multiple non-sequenced LEDs to a battery pack without electrocuting myself would be most welcome.
posted by ananci at 1:06 PM on June 24, 2016

You can get heat shrink tubing in a variety of colours, lengths and diameters. Also very flexible once shrunk. It's electrically insulative and easy to use. You don't have to worry about an injury from shock (the voltage and amperages are very low feeding a small led) but you need to prevent the wires from touching each other and destroying your circuit. IE: putting your finger across the terminals of a 9V battery won't hurt you.

A really small insulated wire can be obtained from a network cable.
posted by Mitheral at 1:57 PM on June 24, 2016

And the power wire should be insulated already. You're not drawing much current, so something like transformer winding wire in a very thin gauge should work fine. Shocks aren't a problem, the voltage will bee pretty low, but you do want to avoid short circuits.

My first thought was wire wrap wire, like a 28 or 30ga insulated wire. Voltage drop over 3'may be a thing, so you might have to use slightly smaller resistors than if you were driving your LEDs off of the battery up close, but experiment with a volt meter.
posted by straw at 12:47 PM on June 26, 2016

I'm going with .029" piano wire as a base with insulated wire for power, and heat shrink tubing over the whole thing to strengthen it and protect the solder connection (thanks Mitheral!). Made my first prototype of the LED tipped piano wire part and it looks super cool! Still on the hunt for a good handle, but will probably fabricate one from PVC and epoxy.

Thanks for your help!
posted by ananci at 6:22 PM on July 27, 2016 [2 favorites]

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