Notices

1. ɗ𐐩ʃƕρʋ (deshipu@fosstodon.org)'s status on Tuesday, 11-Apr-2023 22:14:26 CEST ɗ𐐩ʃƕρʋ

   I always wanted to play a bit with proprioception in my walking #robots, that is, sensing of joint positions and forces, but with the low budget I put on this, I never had a good way of doing that with the cheap 9g servos. Smart servos tend to be much bigger and heavier and much more expensive, and various schemes for reading the position/force by modifying the cheap servos never worked reliably for me. But recently I found those small smart servos that should be straight replacements.

   • ɗ𐐩ʃƕρʋ (deshipu@fosstodon.org)'s status on Tuesday, 11-Apr-2023 22:14:26 CEST ɗ𐐩ʃƕρʋ

     in reply to

     I even received the documentation for their protocol from the manufacturer, and it mostly makes sense, so I'm very optimistic about them. Just like any other smart servo out there they use a half-duplex serial protocol, with data frames on top of that. Now I'm reading about the rp2040 pio assembly in order to implement that, but I might stoop down to just putting resistors or diodes on the RX and TX pins and using regular uart...

   • ɗ𐐩ʃƕρʋ (deshipu@fosstodon.org)'s status on Tuesday, 11-Apr-2023 22:14:26 CEST ɗ𐐩ʃƕρʋ

     in reply to

     I got the little fren to move. And reply to pings and report its position and all that. The examples in the documentation were invaluable, I wouldn't manage to do it with description alone.

     For now I'm using a regular uart with two resistors to turn it into a half-duplex uart, and discarding the data I send and read back. I might leave it like that, it works well enough for my needs.

   • ɗ𐐩ʃƕρʋ (deshipu@fosstodon.org)'s status on Tuesday, 11-Apr-2023 22:14:26 CEST ɗ𐐩ʃƕρʋ

     in reply to

     Some progress on the mechanical side. I had to use the older leg pieces made from PCB, because the 3mm laser-cut pieces are too thick for those smart servos - they have shorter shafts. The PCB just connects all the servos together.

     I still need to write a proper library for controlling the servos, but I don't have any energy left for programming right now.

   • ɗ𐐩ʃƕρʋ (deshipu@fosstodon.org)'s status on Tuesday, 11-Apr-2023 22:18:22 CEST ɗ𐐩ʃƕρʋ

     • Ekaitz Zárraga 👹

     @ekaitz_zarraga I wouldn't know about the toolchain, because I use it with CircuitPython, but generally I can't complain. I want to write a half-duplex uart implementation for the pio at some point, for now I'm just using regular uart shorted with resistors into a single signal.

   • ɗ𐐩ʃƕρʋ (deshipu@fosstodon.org)'s status on Tuesday, 11-Apr-2023 22:20:06 CEST ɗ𐐩ʃƕρʋ

     • Ekaitz Zárraga 👹

     @ekaitz_zarraga It's nonexistent next to the servos.