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Friday, December 10, 2010


We got three out of four hub motors calibrated, which is awesome. The current problem is that the fourth hub motor's sensors decided to idea why or how, because they sometimes work, and sometimes not. It can't be a magnetic field issue because a. they are mounted in the exact same locations on all motors. b. they do change state...except sometimes to the WRONG state. WTF, that shouldn't even be possible. I even tested them with a small magnet and an oscilloscope before assembling the motor, and they worked fine. And we determined it wasn't a problem with the MC board because we ran a different hub motor on it just fine. Oh well. I've ripped the sensors out and am going to put three new ones in at some point. Then reassemble and test again. Then put NEW HUBCAPS on! Wohoo.

Lessons learned over the past month or so:
1. Sensors can fail even when taking every precaution
2. Don't use steel alignment pins (see earlier posts) until the final motor integration onto the board. Pulling those things out sucks
3. Make your hub motor rotors with a water-jet, like this.
4. I should have wound the motors hotter (or just made smaller motors). At 10A, I'll have more torque than I could ever use/stay on the board with. In fact, this board would have no trouble at all running on two motors. Something I will consider if weight ends up being an issue.