First thanks very very much for the replies. They’re very helpful & informative.
What where the moving displays they had at the airport? Last year I did a 7’ tall R2-D2 with a rotating head.
I haven’t seen any other moving can sculptures, but I’m sure they’re out there. He only rotated 90 deg. & the head was only around 200 lbs. so it was much easier then the cube this year.
No I don’t think I’ll try to reverse engineer the controller. I know that’s over my head, but might be fun one of these days…
So you think 4 motors total? So, I’ll need a 4 channel control or 2x 2 channel controls…?
Actually no I didn’t want them to spin consistently in the same direction. I’d like one level to spin 90 deg. then maybe wait 30-60 sec. then spin the other level maybe in the other direction. I was thinking of having it choose randomly which level to turn & which direction it’ll rotate, so it’s not a repeating pattern. I also think it should start out slow, then speed up, then slow down as it comes to a stop at the 90 deg. position. PID, I think it’s called…
I’m so glad you think I should use 30A per channel. The 2x60A controllers seam to be a lot harder to find & a lot of money. It’s hard for me to justify spending $200 on something where the funds are supposed to be going to charity & it’ll only be on display for a week. I also e-mailed these guys: http://store.eurtonelectric.com/wheelchairscootermotorsmodel425500.aspx
since they repair them & they said the motor was 5 amps (pretty close to your 7.5 amps)
There will be what I call a “Rotation Ring”, basically a big circle all the way around inside the cube. Then the motors will spin against that ring. The ring is attached the the plywood below & the motor to the plywood above. It’s like a big turntable. In the first version, shown above, I just had a rubber wheel against the ring (this is how I did R2-D2). But I’m afraid the wheels won’t get enough traction with all this weight, so I want to try to do a geared system, cut on a CNC machine out of think plywood. See the new version attached below, with the correct sized motors & gears…
I’ve already build a small prototype version:
Maybe this video will help show how the rotation is happening. This is of course with the small motors & no Arduino…
Also, note at the end of the video, I can have both motors going in opposite directions to make the middle level spin & keep the top level stationary.
So I have 3 rotation options: top only, bottom only, or top & bottom in opposite directions…
Hope that all makes since. I guess now I have to narrow down which controller to use…
Here’s another questions for ya.
I was planning on using these Slip Rings: http://www.ebay.com/itm/300Rpm-Capsule-Compact-Tiny-Slip-Ring-12-Circuits-12-5mm-2A-240V-Test-Equipment-/390591603081?pt=LH_DefaultDomain_0&hash=item5af112e189 so I can have the batteries at the bottom & pass the wires through the rotation plane. But now that I know I need the higher amps, I don’t think that will work anymore with these thin gauge wires… Maybe I can split the load & use 2 wires for positive & 2 for ground…? If that doesn’t work, I can always keep track of the rotation & be sure to always unwind it, but I was hopping to not have to do that… I was going to use a rotary encoder anyways, so that I can stop it at the 90 deg. faces…
Thanks for the suggestion, but I don’t have the skills to build my own…
This one looks interesting, since it can take 70A, but if I need 2 per motor, then I’d need 8 total & that’s almost as much as the 2x60A from Pololu: