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    Re: Novel leg/chassis design

    I'm not seeing a picture?

    Some contestants have used mechanical advantage. There was a nice two-legged robot a while back that used four servos total (two per leg, for "extent" and "front/back"...
  2. Re: Maker Faire 2019 Mech Warfare (WMFNY in Queens on Sept 21 and 22)

    Oh, that's disappointing :-(
    Thanks for the note!
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    Re: The task (lawn mower topic)

    I know the feeling!

    WHY ... CAN'T ... THINGS ... STAY ... WORKING !?!?!?
  4. Thread: Budget Class

    by jwatte
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    Re: Budget Class

    There's typically one event in a year :-)
    (Except for R-team, which has an Arizona Garage League)
  5. Thread: Budget Class

    by jwatte
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    Re: Budget Class

    Realistically, those "simpler classes" exist for cars/planes/quadcopters because the technology and market adoption of the "main" classes has gotten to the point where that makes sense.
    Walking...
  6. Re: Power for eight (8) Dynamixel XM-430-W350-R

    That should, theoretically, work fine! RS-485 is supposed to work across isolated ground domains (that being one of the main points.)
  7. Thread: Budget Class

    by jwatte
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    Re: Budget Class

    I think the general idea is that the "cam driven" and "statically stable" designs are not in the spirit of Battletech-inspired warfare robots.
    E g, the whole POINT is that it's not easy.
  8. Re: Power for eight (8) Dynamixel XM-430-W350-R

    I agree -- LiFePO4 are nicer in many ways (including number of lifecycles, matching to 12V rail voltages, and fire safety.)
    Unfortunately they seem even harder to come by now than a few years back....
  9. Re: Power for eight (8) Dynamixel XM-430-W350-R

    The Robotis wiring is generally 22 or 20 gauge. 15A through a single 22 gauge wire will heat the wire to the point where the insulation will scorch, even if it's high quality silicone insulation. Or...
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    Question(s) Re: Camera for Arbotix-M?

    If you want a camera streaming to a cell phone, get a GoPro with built-in streaming/wifi support.
  11. Re: Supply robot with 8 MX-64T Dynamixels and measure power

    You can run the MX-64 with 4S LiPo if you either don't charge the LiPo fully, or use a fat diode in line (to drop out a few tenths of a Volt -- gotta be rated for 8A or more on average, though) or if...
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    Project Re: Pololu's Wixel + Arbotix Commander V2

    I tried doing exactly this (with a slightly different OLED) with an Arbotix Commander and a PhantomX quad, but the Xbee turn-around time latency made the Phantom way too jerky in its control. (I've...
  13. Re: Maker Faire 2019 Mech Warfare (WMFNY in Queens on Sept 21 and 22)

    I'm hoping to be able to come. (Need to get serious about finishing my gun!)

    Btw, I find that the "edit the top post" mode of update is good for "what is the latest status" but bad for "what...
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    Re: Maker Faire 2019 Mech Warfare

    All those GoPros gave you some pretty good angles!
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    Re: The task (lawn mower topic)

    That sounds pretty good!
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    Re: Malum Gun Sub-thread

    My boss said her hair couldn't take a garage remodel right now, so re-pouring the pad is on hold.

    However, given that I have neither a sine bar nor a set of angle blocks, I can kind-of squint and...
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    Re: Malum Gun Sub-thread

    @cire, that's a very good point! Thinking outside the box! I shall check with my boss, she probably doesn't need any retirement savings anyway!
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    Re: The task (lawn mower topic)

    Many alternators have a regulator built in, and that regulator is, as far as I can tell, a linear regulator, meaning they sink a bunch of heat to the case when they would generate more voltage than...
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    Re: The task (lawn mower topic)

    That's a fair bit of air :-D
    At that point, the limiting factor may be the surface area of the alternator casing.
    Which leads you to consider water channels, ....
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    Re: Malum Gun Sub-thread

    Turns out, the cutter did get here before today, so I've been cutting! https://amzn.to/2LF11wT

    I now have a bit of a manufacturability problem, though. The 3D printed version works great. However,...
  21. Thread: Rip Van Winkle

    by jwatte
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    Re: Rip Van Winkle

    Double-sided is useful for two reasons:
    1) You can make things smaller!
    2) You can put heat spreading parts on different copper planes!

    Routing traces out from components requires a certain...
  22. Thread: Rip Van Winkle

    by jwatte
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    Re: Rip Van Winkle

    If you think the Raspberry Pi 4 is too weak: Neural networks on drones / robots:
    https://developer.nvidia.com/embedded/jetson-agx-xavier-developer-kit...
  23. Thread: Rip Van Winkle

    by jwatte
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    Re: Rip Van Winkle

    In my opinion, compared to 10 years ago, "motor control" is now a solved problem.
    Back then, some people were still using BJTs and large heat sinks / cooling fans.
    Robust, affordable MOSFETs have...
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    Re: Malum Gun Sub-thread

    I printed a second variant on this idea, and it, too seems to run without catching, so I think I may be on to something.
    I also found an undercutting convex radius end mill that I can use to...
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    Re: Malum Gun Sub-thread

    I 3D printed a slightly wider version of this, and that seemed to work surprisingly well.
    The draw-back is that I don't quite know how to make it using 3D milling.
    A lillipop cutter doesn't quite...
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    Re: ROS Key's update

    The internet is a well engineered system with a robust security model. Any apparent similarity to a house of cards is entirely coincidental.
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    Sticky: Re: Project Khepri - MX 106 hexapod.

    That's funny; my first walker was an all-MX-64 quad with a Zotac mini-box, too. But it was one of those earlier AMD APU ones, not worth the extra weight in the end.

    Have you trained any cool...
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    Sticky: Re: Project Khepri - MX 106 hexapod.

    Very nice!

    I was thinking "can those nylon brackets really carry 5 kg each?" all the way until I saw they were just covers on top of the metal brackets :-)

    What do you use to interface with the...
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    Re: The Raspberry pi 4 Model B

    Neat! Really glad they added Gigabit Ethernet.

    Are there any benchmarks on the VideoCore VI?
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    Re: Maker Media shut down

    RoboGames seems highly unlikely, given that it didn't happen this year ...

    I'm game to visit West Point! Looking forward to see what happens.
  31. Thread: Malum IK

    by jwatte
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    Re: Malum IK

    I've used Seeed before, and I've used MacroFab a few times (up to quantity 10.) My experience with Seeed was "acceptable" and my experience with MacroFab was "great!" MacroFab does charge American...
  32. Thread: Malum IK

    by jwatte
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    Re: Malum IK

    https://www.youtube.com/watch?v=8fnfeuoh4s8
  33. Thread: Malum IK

    by jwatte
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    Re: Malum IK

    SO I haven't been very active on the gun thread, because I realized something else was broken, too.
    The new video transmitter, with "SmartAudio(tm)" 4800 bps half duplex interface, needs a serial...
  34. Question(s) Re: AX12-A not communicating after failed firmware recovery

    Overloading servos can die, for sure. Debugging this is going to require some effort!

    You should add an Xbee or something that can send periodic status information. For example: Every five...
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    Re: DJI releases RoboMaster S1 - Robot tank

    Look at that delicious injection-molded plastic gimbal!
    I wonder if it's separable enough to use on its own? And what the control electronics are?
    Also, seems quite comparable to a mech:


    ...
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    Re: Malum Gun Sub-thread

    Not giving up on this. Just too busy at work to make post-worthy progress.

    A dual-start worm screw, perhaps?
  37. Re: How many hours per week does your team meet to work on anything robotics related during the season?

    That's not enough really to do actual work. Just setting up and tearing down will take a significant amount of time.
    I'd rather use a single three-hour window instead of two 90-minute times.
    That...
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    Question(s) Re: Dynamanager finds mx-28t but not mx-106T

    Are you using "Dynamanager," or the specific "Dynamixel Manager" program that's part of the RoboPlus download?
  39. Re: Why are there two sets of wires going to the electromechanical brake - mobility scooter motor

    Brakes are good if you need to stop.

    Does the "mystery" motor have six total wires? And you think four of those may be going to the brake?
    If so, you might want to measure the connectivity, and...
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    Maker Media shut down

    https://www.theverge.com/2019/6/8/18657824/maker-faire-make-magazine-shut-down-layoff-diy-culture

    So ... no Maker Faire New York, I guess? :-(
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