I’ve been planning to make a telescope with hoverboard motors (direct drive scope) and I’ve just noticed a new release of Odrive pro. I’m planning to make a Light Encoder for it based on the dexter robotic arm GitHub - JamesNewton/HybridDiskEncoder: Hybrid Disk Encoder: A lasercut Analog / Quadrature encoder with more than 1 MILLION CPR. will there be any compatibility issues? is pro better than 3.6 in this case? since it is a telescope, high-speed isn’t a requirement but precision is. (never mind, I’m back to zero in terms of finding a proper encoder, turns out the GitHub rep is incomplete and the project is abandoned )
I have finished building my direct drive telescope called DDScope and it is fully functional. I designed and built my own motors since I needed the torque because the telescope is so big. Much of the telescope is 3D printed. My DDScope firmware is a plugin for the excellent OnStepX telescope driver firmware.
I spent a lot of time looking at encoders. I also tried using a belt and 1:10 gearing to increase the resolution, but the ODrive didn’t support calibration of the pole pairs/phasing when I tried it (I asked). It would probably be possible to support such a scheme my modifying the ODrive FW but you still have to contend with the belt/gear cogging non-linearities.
The encoder I used was a 14 bit version (~$50) and meets my needs since I don’t do astrophotography. But at some future date I may retrofit to a higher resolution as the high resolution encoder prices come down and will check out your interesting links.
I’m using the ODrive v3.6 since that was all that was available when I started and I needed two motor drivers (altitude and azimuth). The advantage of having separate motor drivers with ODrive pro is that the cabling is much cleaner, especially in an Alt/Azm telescope. The disadvantage is two of them is more costly than a single v3.6.
I plan to create a video in the near future of the operation.
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