What Has 114 LEDs And Is Always Running?

The answer, of course, is a word clock. This is actually [Eric’s] second version of a word clock. Like the first one, it uses 114 LEDs to back light the words on the display.

In his first iteration he used an Arduino to drive a Charlieplex array of lights. It was an 11 by 10 grid, plus four LEDs to display the in-between minutes as dots at each corner of the clock face. This time around he’s still using an Arduino, but the lights have seen a huge upgrade. In one of his build pictures you can see the reel of RGB led modules which have two RGB LEDs and an HL1606 driver on each segment. These are SPI controlled, making them easy to hook up, using just a few data and power bus rails. Check out the test video after the break that shows what this grid is capable of.

In case you can’t figure out what time is displayed above, you might check out an English version of a Word Clock face to help in your own build.

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LED Wand For Light Painting Photography

[Michael Ross] is a photographer who has been getting into light painting recently. He’s come up with his own RGB light wand to create some amazing images, and also written a very, very thorough tutorial (PDF warning) on how to build your own light wand.

The light wand is based on an Arduino Mega board and uses an RGB LED strip based on the HL1606 controller chip. We’ve covered these LED strips before, and they’re very easy to use with the requisite library. So far, [Michael] has built a 48-LED light wand and a 16-LED wand with a 6-position program selector, making it easy to do awesome single-exposure photos like this.

[Michael] creates his images in an Excel spreadsheet – rows are which LED to address and columns are units of time. The picture data is then copied and pasted straight from the Excel worksheet to the Arduino source code. This in itself is a pretty clever use of Excel.

Check out the how [Michael] creates one of his light paintings here.

Addressable RGB LED Strip


[Synoptic Labs] stumbled upon an RGB light strip with individually-controllable LEDs. The strip uses 5 volts and is controlled by an HL1606. Because the strips are hard to find, this chip is mostly undocumented and he had trouble driving the strip. He was unable to get it working until he met with [John Cohn], who had previously reverse-engineered the serial protocol. Working together, they released a library for the Arduino to drive the strip. So far, the library only supports fading each LED, the only known functionality. If more strips like these were available, constructing LED matrices would be much easier. Embedded below is a video of the strip fading through the rainbow.

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