Billboard Thoughts

I’m collaborating with my friend Raven. We’re still at the drawing board but we’ve talked about those billboards that change images using rotating triangles. It’s a cool way to incorporate more than one frame of content into a painting.

Initially I was thinking of using a timing belt to move all the slats in unison. Michael and I thought of controling the slats independently so we could get some wave effects. He suggested an LED driver and a system of coils and magnets to control the slats. I like the approach but I’m concerned it might take me a long while to get it working and tune it. Perhaps a later version can have that once I have it figured out.

I decided to make one with two frames since it looks the easiest. I made up a simple 6″ slat riding on rare earth magnets to help me visualize the problem. This  3D object really helped me (plus it’s fun to fidget with).

I decided that the easiest way to control the slats independently was with an array of servos, a micro-controller and servo controller (or an Arduino Mega). With 180 degree servos, I could have the standard servo horn plug into the slats from the bottom. Then the magnet bearing could hold the slats in from the top.

But most servos might be short 180 degrees of rotation so I may need to do something fancy to couple the servo to each slat. I could make gears such as the ones in my Spirograph Business Card. I used the Involute Gear Plugin to make a .8″ and .4″ gear. I figured that should give enough clearance since the slats are 1″ apart in my SketchUp mock-up.

An escapement is another interesting idea for a future version.



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