tamilkamathaigal

OK, this one isn't really a project. But I wanted to share it anyway. One day a bought this little ...light thingy in a junk shop. I didn't really know what it was, but it had LEDs and anyway it was only 1 €... This is what it looks like: It turns out that it has three very bright LEDs in red, green and blue and it works in different modes; one of them is a colour change mode. But it does this

Some time ago I stumbled over an article about charlieplexing on hackaday.com. Charlieplexing is basically a method to control n * (n-1) LEDs using only n I/O ports of a microcontroller. Say you have 5 I/O ports, then you can control 5 x 4 = 20 LEDs independently! Find more details in Wikipedia. I was fascinated, because I had never thought it was possible to control so many LEDs with so little