Make your Hello world! LED project a little more jazzy with these rainbow LEDs. All you have to do is to provide power, and they'll cycle through all the colours of the rainbow!
These 5mm LEDs look (from the outside) and work just like single colour LEDs, except that they cycle through every hue at three different speeds (fast, medium, slow) one after the other.
In our testing, these LEDs will work happily at either 3.3V or 5V, and have a maximum current draw of 60mA at 5V. Bear in mind they don't have any protection against reverse current, so make you connect them up the right way round (long leg to +/power and short leg to -/ground)!
LED diagram by Sparkfun, shared under a CC BY-SA 4.0 license.