Posts with «charlieplexing» label

Lite Brites fade, but LED clocks are forever

Ahh, the Lite Brite.

What could be more fun than pushing dozens of little plastic pegs through a piece of black paper in order to create a pixelated, though colorful image? Well, I can think of quite a few things more engaging than that, and luckily so can [Lonnie Honeycutt] over at MeanPC.

While contemplating what to build with a pile of LEDs, his daughter came into the room with her portable Lite Brite. He thought that the pegs she was using looked awfully similar to the LEDs on his desk, so he did some test fitting and was surprised to see that they fit almost perfectly.

[Lonnie] thought that the toy would make an excellent clock, and his daughter happily agreed to let Dad do some tinkering. A few hours, an Arduino, and some Charlieplexing later, he had a nice looking clock that his kids were sure to enjoy.

If you’re interested in seeing more about how constructed, be sure to check out his YouTube channel and Instructable, where he happily provides all of the build details.


Filed under: arduino hacks, led hacks, toy hacks

Led as light sensor [Arduino]

If you connect led in the opposit way he can act as light sensor:

positive leg to analog pin

negative leg to 5V

You can use that for some things, but he not sensetive as LDR,

ןf you use a for example a green led he not "see" well red light

If you use charlieplexing method you can control one led to light and as a light sensor.

The idea is like this:

Two wires connect the led to two analog pins.

To light the led you set the two analog pins as digital output and one high one low. 

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