Gonna have to switch to glass mirrors

Here's a picture of the reflection made by the 2' x 4' piece of mirrored acrylic I've been using.

Here's a picture of an ordinary, glass mirror. About 2' square. Yeah. The acrylic isn't really going to work.

So, back to glass. Ikea sells this for $8 on their website, $10 at my local store. It's about 16" x 48". I was planning on using two, which gets very close to 1 square meter. So glass costs are $20/meter square. Which is much cheaper than the acrylic. The downside is only weight, and perhaps breakage. Ikea also has these for $5, which is $1.25/ft2 = about $15/sq meter.

Version 2.2

The best is the enemy of the good so I'm just going to stop procrastinating and post. Here's a couple pictures of current status. First an overview against a yellow wall.

Next, the same again, closer and from below. It's easier to see the linkages from here.

And, a close up of where the motor interfaces with the threaded rod.

So the changes in this version are...

1) The way the motor connects to the angle iron is simpler and better. I laid it out so the threaded rod would go through one of the round holes, let that determine the position of the motor, then drilled holes to mount the motor.

2) It uses a tee-nut instead of a gear. The version in the last post used a 1/4" bolt that was clamped to the motor shaft. That kept falling off so for this I drilled a hole through the motor shaft and put a #4 machine screw through it. It tended to catch its threads on the tee-nut, so I took a dremmel to the end of it to smooth it and that helped. In retrospect (or for a next version), it might be easier just to pre-drill a hole in the shaft then drive a nail through it. The tee-nut is a rare 6-prong version. That works well because it only has to be turned 60 degrees per motor rotation (it's more forgiving than the 4-prong tee-nut -- you can put the motor farther away). I like the tee nut for being cheap but it makes the interface a little finicky. Longer term I'm tempted to make real gears (maybe with this!), because if it ever went to production, it'd be easy to have gears manufactured cheaply.

3) The piece that keeps the threaded gear from riding up (top cap?) is done more neatly. It's an L-bracked that is bolted to the back of the angle iron and then the L comes over the top so the threaded rod goes through it. Works well, though it's one more thing to make. It probably needs one at the bottom of the rod also to help define the threaded rod's path as perpindicular to the angle iron.

4) The way the threaded rod links to the mirror actually works (and it's still not super stable). When I ran the motors to move the threaded rod and tilt the mirror in v2.1, it would get out of alignment. The addition of a second in-line ball joint fixed that issue for now.

5) There's a brick supporting the long angle iron. This wants to be another 8" high cinder block but I have not gotten to the store for that.

So it's better, but still not where it needs to be before it's worth documenting and field testing.