My LED Darkroom Safelight
Today I decided to get those parts I had laying around into a useful darkroom. I boarded up the bathroom window, make some workspace and then wend to Radio Shack to get some components for the LED safelight I wanted to make. I wanted to go LED because they put out a specific wavelength, in the case of red, my LEDs are about 640 nanometers (I forget the exact figure but it's -+10 nm). I used 2 1W high power LEDs powered by a 9V battery, calculators online can tell you how big a resistor is needed given the arrangment of LEDs and the power requirements of source and forward voltage etc. I popped all the junk into a project box with a switch and there we go. Its really bright and shows no signs of fogging the paper I was cutting and getting ready so far. It's bright enough that it lights up the whole bathroom when placed on the closet door, bouncing off the ceiling.