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About ord

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  1. @Jonas That's right about the tread link. I think it could be enlarged, I was just restricted by my longest axles being 12M. With 32M axles it could be enlarged significantly I think. @NikosSprocket thanks. It was programmed using Pybricks.
  2. @Jonas thanks! Correct, just a standard cylinder.
  3. Here is my latest MOC; a 3DOF cartesian parallel robot with suction gripper. It is capable of lifting small parts within a work envelope of 7x7x5 studs.
  4. What I meant by "exit the program" is to click the back arrow at the top-left of this screen, which I think might save its current state:
  5. @allanp I've been facing the same problem with the keyboard not showing up (I upgraded to Android 11 and app version 3.6.0 recently so maybe it's because of one of them?). As for the programs not saving, I feel like when this has happened to me it's been when I've closed the app without exiting the program but I could be wrong.
  6. Thank you . I don't see why it couldn't be stacked (to make a 0-99 counter, if that's what you mean). That would actually be pretty cool; it would just require a mechanism that steps every 10th rotation and can handle a reasonable amount of torque.
  7. Version 2: I'd like to present version 2 of this MOC. Taking inspiration from aeh5040's seven-segment display, this version features: Control by a single shaft/motor Number incrementing and decrementing Faster response time than version 1 Unfortunately, mostly due to the goal of having only one input, this version doesn't feature a 'minus sign' segment.
  8. Perhaps you could deduce more accurate angles from the accelerations in x/y/z.
  9. From my experience with a similar project but with an Android device: - As @David Lechner said; long, smooth accelerations work best. - Even with long, smooth acceleration, data inaccuracy will build up quickly. You will likely want to record the data at a high sample rate but whatever rate you choose, that will be the rate at which inaccuracies accumulate. These inaccuracies might come from rounding or from the sensor itself. - It is impossible for the device/hub to know when it has come to a standstill without some outside input (a constant velocity is the same as a a standstill in terms of acceleration). Because of the previous point, when returning to a standstill from movement it is highly likely that your calculations will show that the device is still moving and hence your distance measurement will drift. This drift will also occur during movement. - Treating velocities of say -0.1 to 0.1m/s as 0 did help prevent drift at standstills for me but introduced other obvious problems. Good luck!
  10. ord

    General Part Discussion

    This is great news - if I understand correctly, 2 stud wide chain drives will now be possible with these sprockets (down from the previous 5 studs)
  11. I admit, there is something nice about having the axes in the same plane. If you were to control it with linear actuators you could do away with the lower turntables and have it mounted on pins, I think, to streamline it a bit. I wonder how luffing is driven in the actual machine...
  12. You could mount the boom axis above the luffing axis (rather than on the same plane)? This looks like how it's done in the Gradall excavator photo you attached. This could also lend itself well to controlling luffing by linear actuators, if you want to go down that path. Great project btw - it has a lot of similarities with an industrial robot arm. Well, I guess it kind of is a robot arm... on tracks
  13. Nice robot arm! I'm working on one myself so will be following this thread. I haven't done it before but was considering using the Robotics toolbox for Matlab to simulate the arm and get joint coordinates to plug into python. Any idea how you might approach it?
  14. ord

    General Part Discussion

    I imagine the notches are there to allow the inner core to slide out during molding.