20 Nov

8×8 RGB LED Grids – the build

Here’s the list of the major items for the build

  • WS2812B RGB LEDs strips
  • Fadecandy module
  • 3mm MDF board (laser cut)
  • Frosted Perspex

Here’s the project outcome.., 8 x 8 LED grids connected up as a 2 down 2 across. All LEDs are illumined with the full brightness test pattern from the Fadecandy server web page. You’ll notice that there is a slight impurity in the ‘white’ because of the different performance of the red green and blue LEDs within the WS2812B. In practice multicoloured patterns are shown so this is not noticeable. Frosted Perspex is used to diffuse the light. A future design may secure the Perspex in a channel within the MDF as no amount of hot glue secured these well enough.

Multiple 8 x 8 grid with a ‘white’ RGB LED signal

This is the rear view showing the LEDs zig zagging across the LED mount panel. The MDF panel is on the shoulders of a narrow piece of MDF around the inside of the frame. LEDs in strips of 50 were purchased so an extra strip had groups of 14 unsoldered to make these up. The 64 were then rolled without twists onto an old ribbon cable spool so that is was easy to unroll flat onto the LED panel. Heavier hook up wire was taken to every 16th LED to cure any dimming of the LEDs at the end of the strip.

64 LEDs zig zag and glued to an MDF board

To make the cubes in to which the LEDs shine 3mm MDF was laser cut into narrow slotted strips, 7 horizontal and 7 vertical. The cube size is about 52mm. MDF ‘staples’ were also cut and within the mount panel you can see 10mm diameter holes for the LED and the staple arms to be accepted. Each LED and staple were hot glued.

Laser cut MDF sections to make cubes

A custom loom was made with heavier gauge (16AWG) hook up wire for the ground and +5V – 64 LEDs take about 2 Amps at full brightness. When soldered onto the pins and the crimp folded over this just fits the JST connector. For mobile use power was taken from a 12V car battery with a 5 Amp DC to DC step down buck converter module adjusted for 5V output. One per 8 x 8 grid and again part of a loom – à la spaghetti junction – manageable with only 4.

Using the Fadecandy module and the Processing.org IDE the project was quite code light.

  • Code to write patterns to the LEDs was just a few lines
  • Libraries for images, video and audio are easily available
  • Processing code and Fadecandy’s fcserver could be a computer that we could leave at an installation (e.g. Raspberry Pi)

Sample Processing.org code for this project is available on Github…

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