parts and musings

I finally got a response from Hosfelt Electronics. I think they may have felt a little bad about taking so long. They shipped it yesterday (5/4) and it's scheduled to come tomorrow, so that's better. Yesterday, I also ordered 40 of the LED driver chips as well as a shit-ton of random stuff from Digi-Key. I knew I would need a lot of stuff from there and I already had a pretty big list of stuff picked out, so I ordered lots of surface-mount discrete components (resistors, caps, diodes, current limiter chip, voltage regulator), a few headers and connectors I figured I'd probably use, a bunch of tools for various tasks (tweezers, PCB vice, crimper, scalpel, breadboard, etc), and 2 sensors. I've been kicking around ideas about what else to do besides just lights. I can't really do touch sensors on a wall piece, so I started thumbing my way through the catalogue and came upon quite a variety of sensors. Two that struck my eye were a surface-mount illuminance photo-IC sensor and a distance measuring sensor. So I picked up one of each to give them a try.
The illuminance sensor measures about 1 to 3000 Ix and has a peak wavelength sensitivity of around 600nm. The wavelength response range is from about 350nm to about 825nm (visible light is between 400 (violet) and 700 (red) nm), so it reaches into IR a little bit (not a real issue, and could be rather useful). The output is analogue, so I'd need to send this through an ADC and then read off that.
The distance sensor is really quite sweet... I can't wait to get it so I can try it out. It's rather large (37mm x 19mm x 13.5mm tall), so that could be an issue, but I might be able to disguise it a bit. It's a nice all-in-one package. You just give it 5V and it outputs some voltage between ~0.5V and ~2V based on how close a "reflective" object is to it (I will need to experiment with how reflective objects need to be). The distance range for the one I ordered is 10cm to 80cm (4in to 31.5in), which is a pretty decent distance. Since this is an analogue output, I'd need to send it through an ADC as well.
What I'd like to do with one or both of these parts is place a few of them around the full pixel wall. With the distance sensors, I could have the wall react if anything came within range of it (and change the reaction based on how close the object was). Multiple sensors could be read to determine approximately where an object is (it could obviously be easily fooled). The distance sensors aren't exactly cheap either, so I would probably have maybe one every 1-2 feet.

I've been playing around some with the idea of using triangles instead of hexagons. Hexagons can really be thought of as 6 equilateral triangles (or 2, if you take the big one in the center and then the 3 smaller 1/3rds on the sides), so there's really no aleration I need to do to use triangles other than adjusting the side of them. The only thing that might be an issue with triangles is keeping the light diffused across the entire triangle face, especially in the corners. I'd have to make the walls thin enough (at the top anyway) to get color all the way to the edges.