I have been playing around with simple ways to make patterns on LED arrays.

Here’s one demonstration of how the same numeric pattern looks on a regular “square” array (cartesian coordinates) and on a circular or radial array (polar coordinates, you could say).

The circular array is quite suited to my work, because I am working with repetitive patterns and polar coordinates are usually used for things that repeat, like rotating planets or the sine wave that comes out of your wall socket.

Here we have a demonstration first of what **x=y** (cartesian) looks like on square and circular arrays. On the square array it’s just a diagonal line from the lower left corner to the upper right corner. On the circular array it’s a spiral.

When I flip the switch to take the x and y signals out of synchronization, where (in this case) x and y are different by about a ratio of 2 to 3, we get a slowly moving slanted line on the square array and a pulsing pattern – basically a set of spirals – on the circular array. So this condition looks more interesting. Many patterns are possible using this sort of system, and this is one thing I’m working on while stuck at home.

### Circular arrays

Circular arrays that use base-2 numbers (8 or 16 for instance) are, as far as I can tell, non-existent as manufactured items. That means I have to make them myself. Here’s what my recently-constructed 8-by-8 array looks like in the back:

Without going into laborious detail, you can see this took a bit of work.

I continue to look for pre-fab boards with circular patterns, but so far have only found ones used for clocks (12 points in the circle, or some multiple of 12). Digital ICs (old school CMOS) almost all use binary counting. As the standard IC has 16 pins, the most places you can pull out of one is 8. The binary number comes in as 3 bits (up to 8 places) or 4 bits (up to 16 places) and can be resolved to 8 places with one IC, or 16 with two, etc.

I may learn how to design my own boards for this purpose. We’ll see about that.

Tags: electronic art, math

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