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About GroundskeeperWillie

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  1. GroundskeeperWillie

    Reverse Kinematics and Path Planning

    Yes, but from watching the video it's pretty clear to me that he is not using pre-determined movements but rather set coordinates with calculated movements, probably using a model that knows the arm's geometry and limitations. But since he doesn't discuss how it's modelled and implemented it doesn't help much. I've been using the Java Mindstorms OS, LejOS quite a lot and it has great abstractions for many robotics tasks. But again, unfortunately, they are mostly aimed at controlling/pathfinding in 2D, not 3D. This is just to say that your suggestion to create an open source python project is probably the best way to go about it. Good luck! From a quick look, this looks promising. And you're right, doing this math from scratch is a monumental task. I've been a developer for 2 decades but since I've mostly been doing high level work, I still find robotics really difficult and I'm always struggling to find the right abstractions. But they already exist and it's just a question of finding those that match the problem at hand.
  2. GroundskeeperWillie

    Reverse Kinematics and Path Planning

    I can highly recommend watching this video from Akiyuki. Especially the second half has many details about its motion. Unfortunately it doesn't get much into programming details.
  3. GroundskeeperWillie

    Torque and power - some insights

    What a great idea combined with great explanations and the experiment to match. Wonderful!
  4. GroundskeeperWillie

    LEGO railway crossing 4539 automated with Mindstorms RCX

    You could use a rubber band in the transmission which will allow the motor to slip once it reaches the extreme positions. Then just use a timer than runs slightly longer than necessary. Then it will remain in sync without a rotation sensor. Alternatively, you could change the gearing of the rotation sensor to make it turn slower and thus increase the measurement precision. Let me re-phrase that. Making the rotation sensor turn slower will actually decrease the precision, but this is probably what you want. If it goes out of sync, it probably means it turns so fast that some ticks are skipped.
  5. GroundskeeperWillie

    Do you use 1.2V or 1.5V batteries?

    Thanks for sharing @MikeTwo9398.It's too bad about the lower capacity but it does seem to work fine nonetheless. I'll consider this for my Control+ and Mindstorms hubs as they are a little tame with 1.2V batteries in them.
  6. GroundskeeperWillie

    [MOC] Old little tractor RS09

    That's a cute little tractor. Looks very authentic. Well done
  7. GroundskeeperWillie

    Do you use 1.2V or 1.5V batteries?

    It seems there are also 3.2V AA 14500 LiFePO4 rechargables. 3 of those come really close to 6 alkaline in voltage. Has anybody tried those?
  8. GroundskeeperWillie

    About powered up compatibility

    There is an ongoing discussion on about app-less control options. Doesn't look too difficult although it does require building a controller with custom electronics.
  9. GroundskeeperWillie

    Grass seeding robot Lego mindstorms EV3

    Awesome! Very well done.
  10. GroundskeeperWillie

    2020 Mindstorms set

    Did anyone explore the possibility of bluetooth connectivity between the smarthub and NXT or EV3? It seems it should be possible, right? I'm kinda fond of using Lejos and its workflow but would of course like to be able to integrate the new stuff.
  11. GroundskeeperWillie

    Nico71's Creations

    Great work! I can hardly imagine the work that must have gone into this marvelous machine. The programming mechanism reminds me of this "punch card" programmable crane from the 8888 ideas book, published in 1980:
  12. GroundskeeperWillie

    [MOC] Kverneland FastBale - Non stop Haybaler

    This is an amazing build I have sometimes considered building a baler but have always given up fast because I could not find a way to cut features to avoid it getting too complex. It's incredible how you have just taken all features and the full complexity head on and solved it too! I'm gonna watch that video quite a few times