Spudlights

[Mutie]

Back before super bright LEDs came out we started building Spudlights which are clusters of LEDs on an 12awg wire covered with split loom tubing. Recently I just started using LED reflectors from theledlight which I really like since I can use a single bright LED and still looks otherworldly. I still use clusters if I want a bug eye appearance or multiple colors. (Red and blue being the best combo.)

Using Spudlights as a base these are put on the back of wrist guards to make LED fingers or put on headbands to make antennae. Which are then covered with fluorescent latex monster skin. The LED fingers look very similar to Wolverine's claws.

Each cluster consists of strings of 2, 3, or 4 LEDs in series to run off a 9v transistor battery. Direct drive, no resistors. Old LED tech is figured at 2.2v and new is 4.5v (I know that is overdriving slightly but it works). 9v clusters are then wired in parallel if I want more. I have run up to 20 LEDs with run times of 8 to 24 or 30 hours of decent brightness (and in my apps I want max) depending on how many LEDs are used. I noticed in discussions on resistors for parallel (not that I plan on using them but it has raised questions and could explain some weirdness I've encountered) that rather than placing a single resistor before the parallel split each leg should have it's own resistor. Any comments or insight on this? Also these are usually run for 3 to 8 or more hours continuous.

 

[carbonsparky]

When you said "spudlight" you made me think of a science fair project I assisted in. A co-worker's son needed a science fair idea. The idea of a potatoe battery came up and I suggested being able to power a light with the battery and offered to part with one of my 5000mcd white LEDs. I never did see the spudlight but I was told it did work.

The reason for using sepearate resistors in parallel LED strings helps ballance out the current flow. Each string will have a slightly different forward voltage drop. With one resistor the one with the lowest will take more current, possibly even to the point of over currenting the LEDs,and effecting the balance of light output. Having a seperate resistor allows for smaller wattage devices to be used and will ensure each string is running on the desired current.