If you're following along, at this point you have the grid8x8_orbits example running on your NeoMatrix. It looks like this:
It's a really simple example, but there's already a lot going on. There's a huge range in brightness, from pixels that are just barely on to pixels that are blindingly bright. Colors mix in the center. By themselves, the LEDs convey some of this, but there's also just an overwhelming sense of brightness that results from the light being so concentrated in each pixel.

In a sense, what you're doing now is staring directly into a light source. It's really extreme, and it's attention-grabbing, but there are a lot of other aesthetic options for a project like this. The lights could be illuminating an object, or they could be casting shadows, or they could be projecting a pattern onto a surface.

This is a great time to experiment with different materials, to get a sense for what the LED light looks like under different conditions. Maybe this will give you ideas about other materials you'd like to try, or other visual effects you want to design.

First, a simple piece of printer paper. I folded each edge down into a sort of box-lid shape, so that it's separated from the LEDs by a fraction of an inch. This gap gives the light some distance to spread out before it hits the paper.
The paper acts like a rear-projection screen. In signal processing terms, it's also acting like a low-pass filter or blur. The hard edges of each LED are filtered out, and the result looks much more like what appears on-screen.

Next, let's take the same piece of paper, crumple it up, then flatten it. This adds a lot of interesting texture, and you can start to see how the moving light interacts with a complex 3D object.
Objects that cause interesting shadows and reflections are especially fun. If you have glass beads, marbles, or other small non-conductive objects, you can try piling them directly on top of the NeoMatrix. This is what it looks like with a pile of opaque white glass marbles:
Once you get an idea of what shapes look interesting, you can try fabricating your own. This is a shape I made with a Makerbot 3D printer:

This guide was first published on Nov 20, 2013. It was last updated on Nov 20, 2013.

This page (Play with light) was last updated on Nov 24, 2020.