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| Very off topic, a simple LED circuit needed. |
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| JonnyBoy:
Hey guys. I am working on a project for my halloween costume for school (it's a competition and I don't want to lose). I have this really campy cobra-head cane. I want to drill out where the eyes are and put in some LEDs and make the glow, for the extra cheese factor. Now, I can get LEDs and resistors and all that, I just need to easiest way to make a small circuit capable of running 2 LEDs (green) using a battery or something. Any advice would be great. Thanks. |
| Buddabing:
Without knowing your LED specifications, it's impossible to give exact numbers. Let's say your LEDs require 20ma of current and drop 2 volts each, and you're using a 9 volt battery, like are commonly used in smoke detectors. This is pretty typical. For simplicity you can put everything in series. Battery, LEDs, and resistor. To calculate the resistor, use v=i*r. V=the remaining voltage that is not dropped across the LEDs, which in this case=9-2-2=5 volts. i=0.02 amps (20 milliamps), This gives R=250 ohms. You can google for much more detailed info. The first link I got was http://unclean.org/howto/led_circuit.html Regards, Buddabing |
| Gambit:
What would be cool, would be pulsing LEDs for the eyes. Not flashing on and off, but slowly growing brighter then slowly growing dimmer. |
| BobA:
Here is a circuit sold to fade on and off. Used for LED eyes. The picture will give you an idea of the parts needed if you want to build your own. http://www.cowlacious.com/LightProd.htm |
| MikeDeuce:
http://www.instructables.com/id/E9D2ZJ3FG0EP286JEJ/ Since it sounds like you just need it for a few hours, a flat battery, some wire, and a couple LEDs would do it. |
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