Looking to start building the frame soon and do the electronics work in June when I have a break from school. I was just wondering if anyone has seen/ has an opinion on the these “servo-steppers”. Aside from the inherent risk of kickstarter and the lack of torque info I am interested in doing my build with these.
You could also look into odrive. The board supports step/dir input so you should be able to drive it from a rambo (or whatever) in a fairly straightforward way. I would love to see this, and it should be straightforward enough, but I dont think anyone has done it so far.
I would say build with regular steppers first, then change over to the servo drive, or else you might be fighting multiple problems at once and it would be hard to get to the root of it.
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Interesting product.
I started to look into servo steppers a week ago or so. My initial interest was just to measure the actual stepper angle very precisely without any closed loop control. But the more I thought about it, the more interesting I think a servo stepper can be.
Most affordable servo steppers (Mechaduino, uStepper, Misfittech.net smart stepper) I found can be controlled with step/dir signals. While that may sound simple, long wires are susceptible to electrical noise. This makes the servo see step and dir signals that are not there. So Marlin and the stepper get out of sync.
The AnanasStepper is actually the first affordable one that does not have this drawback, if you can use the RS485 or CAN interface. But that would still require you to have some way of converting the step/dir signals to RS485 or CAN.
They list 0.54 Nm “static moment”. I guess that’s the torque. Sounds high for a 40mm long stepper, but it’s possible I guess.
I actually designed a circuit board just last weekend that does essentially the same as all these servo steppers. I also designed a little board that you connect directly to your main board, and which translates the step/dir signals to RS485, so you can use long wires to your steppers without any issues. Both boards have a 48Mhz 32bit MCU that I can program in any way I want. I have ordered it from JLCPCB, including assembly. I just need to solder on the headers and flash some (self-written) firmware onto it. And here’s the good part: the assembled PCBs to control 5 steppers only cost $72 total (+ $21 shipping)! You do need a separate stepper driver though, but I have those already. All other servo boards I’ve seen are around $50 each, and do not include a board to get noise free communication.
Anyway, the boards will only be produced after Chinese New Year (Feb 1) and it’s the first time I designed a board that includes a CPU. Hopefully I didn’t make any mistakes, fingers crossed.
All that said, I agree wholeheartedly with Jamie, build with regular steppers first, and only then change over to the servo drive. Most of the servo drives are add-on boards anyway.
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