Building a motion control camera…

Ever notice that the most popular and successful consumer robot is the camera gimbal? DJI Osmos and drone gimbals are sold by the hundreds of thousands— and they are basically camera stabilizers that use brushless dc motors with feedback for control… rather than servos or stepper motors. They are very fast, precise and can handle heavy loads (the Ronin can handle 5 pounds— and costs less than JUST ONE Dynamixel pro that handles that weight!)

I have a particular set of cinematography moves I need to make repeatable.

I’m doing a project that requires a motion controlled camera… but I can’t use the industrial robot based platforms out there. ( due to cost but also size. They are way more than I need.)

I can stick a commercial gimbal like a ronin on the end of a crane/job though. Then I just need to move the job up and down. Or left and right. (The Ronin can be programmed to make its own motion control moves.)

I’m thinking of a weighted jib as the basic mechanism so the arm is balanced and less power needed to raise it. It will move very slow- compared to most robots. Slow enough to bore humans watching it.

But it needs to be very precisely repeatable.

I only need two axis— one up and down to swing the arm up and down and a second left and right across about 80 degrees of rotation max. Imagine this guy:

http://maiamedia.co.uk/wp-content/uploads/2011/08/kessler-crane.jpeg

At the beginning of the move the jib arm is close to the ground and facing left and at the end it is up high and facing right. Max speed for such a move would be 20 seconds. Sometimes would set it to take hours (for time lapse.)

Looked at Dynamixel but they are extremely expensive. Found these and they seem ideal : https://www.hebirobotics.com/hebi-team but “call for quotes” makes me thing expensive.

For both axis I can put gearing in to make it less stressful on the motor. The weight is balanced by the weights on the other end of an arm (I literally want to automate a model of the crane above but will be a DIY version of the crane.)

Just need suggestions for a good motor I can turn a precise number of times in each move.

Will be driven by a raspberry pi.

Best I have so far is this : https://www.phidgets.com/?tier=3&catid=23&pcid=20&prodid=1121

https://www.phidgets.com/?tier=3&catid=24&pcid=21&prodid=353

Any ideas of a better solution? Right now I think those phidgets are a good choice, easy to program, and while “expensive” they are cheap compared to industry products.

submitted by /u/gorobophoto
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