Raspberry Pi Switched LED Nightlight

thingiverse

This is an LED nightlight that can be powered directly from Raspberry Pi GPIO provided you use only one LED and a low value resistor such as a 10 or 22 ohm to get something like 3v and 14ma. To create brighter lights, you can add more LEDs in series, but then you need to supply higher voltage and switch the light on and off with a transistor. This nightlight works great with: 1 White/blue/pink lights on 3v, using a 10-22ohm resistor straight from GPIO 2 Red/orange lights on 5v, using a 39-47ohm resistor for each pair, switched with a transistor I've gone as high as 8 white LEDs or 6 red LEDs powered from a 12v supply, but that's overkill for such a small light.