Instructables

LED on the spark plug wire?

I would like to attach a string of LED's to run off of the spark plug wires on a motorcycle but I don't know where to start, but it would look awesome flashing under the tank at night, any takers?

and7barton5 years ago
Use a Neon ! - I used one on my Gas Turbine engine - simply cut the spark-plug cable and inset the neon in-line.
NachoMahma5 years ago
. Neon bulbs (or tubes) might be a better choice. As CameronSS points out, LEDs are very low voltage devices and will probably fry without some sort of interposing trigger circuit.
lemonie5 years ago
Wire them into the 6 / 12V supply, but take a trigger from your ignition circuit. I guess you've got some kind of Magneto - you might be able to add an additional small coil that will trip a transistor circuit.

L
CameronSS5 years ago
That does sound like it would be cool. However, keep in mind that LEDs usually run off of 1.5V-3.5V, whereas spark plugs can use anywhere from 40,000V to 100,000V. If you want to run it off the spark plug wires, you will probably be better off with neon or fluorescent lamps.

Actually, you could possibly even run them wirelessly: if the electromagnetic field around the wire is strong enough, simply placing a neon lamp or fluorescent tube next to it will make it light up. If you don't have one handy in your junk pile, you can pick a small neon lamp up cheap, which you can simply hold up next to the spark plug wires with the engine running to test the concept. I'd try it for you, but I don't have any engines around here with exposed plug leads.