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  1. Thread: MX-106 speed

    by jwatte
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    3
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    314

    Re: MX-106 speed

    Money can buy you anything :-)

    The Dynamixel Pro series has two encoders, one for position, and one (higher resolution) for velocity. They may do better for the velocity read-back.

    There are...
  2. Thread: MX-106 speed

    by jwatte
    Replies
    3
    Views
    314

    Re: MX-106 speed

    The servo has to run the PID loop and compensate for all kinds of mechanical forces like friction, backlash, and so forth, and runs this loop on a very small time step where the difference between 5...
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    Re: USB2AX firmaware update

    Maybe COM3 isn't the right COM port?
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    Re: TTL bus has a mysterious pulse on it

    The original post was July 23 of 2017, so not that long ago.

    It has, however, stood the test of time, for now. The 'bot this is on did take second place at the autonomous RC car racing in Oakland...
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    Re: Robogames 2018 Ideas and Suggestions

    Another way to think about it: Each panel regain the ability to subtract a hitpoint every 20 seconds, but the 'mech only regains one hitpoints' worth of health every 20 seconds.
  6. Replies
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    1,966

    Re: Robogames 2018 Ideas and Suggestions

    Probably best to illustrate in code :-)

    Here's a sketch for code that could run on the scoring board:



    #define HEALING_TIME 20000
    #define PANEL_HITPOINTS 10
    #define TOTAL_HITPOINTS 15
  7. Discussion Re: Servo won't turn while accepting commands from an Arduino

    I don't know! WHat does your servo need? What servo is it?



    If there is not a shared ground between Arduino, servo, and battery, then the signals from Arduino won't make it to the servo....
  8. Discussion Re: Servo won't turn while accepting commands from an Arduino

    9-volt batteries are bad for two reasons:

    1) The voltage 9V is way too high for what most RC servos expect. Most servos expect something in the 4.8V-6.0V (4S-5S NiMH) range, and "high voltage" RC...
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    Re: How do we get kids interested in robotics?

    I think the main problem is that a lot of people think that $500 is a lot to pay to educate kids about robotics, because they might not like it, and thus it's "an expensive wasted toy."
    Presumably...
  10. Question(s) Re: RX_TIMEOUT error when setting power to Dynamixel Pro - Raspberry Pi

    Trossen does not have a factory in-house. They, like most other people who sell electronics, contract the manufacture of their electronics boards to electronics manufacturers (colloquially called...
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    60,152

    Re: PhantomX controlled by a Raspberry Pi

    From the picture, it looks like a Model A. It has the big SD card, and the shorter GPIO pin header, so it's one of the first batches.
    Anyway, if the TTL out on that serial converter is 5V, and he...
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    Question(s) Re: ArbotiX avrdude error

    Yes, ICSP "always works" as long as the chip has power; much easier to recover from bad programs.
    And, yes, ICSP works even when there's a Xbee plugged in, or something else uses the serial port....
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    464

    Question(s) Re: ArbotiX avrdude error

    Do you have an Xbee attached to the board? If so, the Xbee will be getting in the way, and needs to be unplugged before programming.

    Personally, I've found that the serial bootloader nonsense...
  14. Re: Self-navigating rover, and how to ruin an AX-12A

    When the wheels spin/turn free, there's no problem with the gears. It needs significant torque to push the gears out of alignment.
    It didn't happen yesterday at the races; the surface there was a...
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    Re: Money Pit V for Victory

    In what way? That training run would have placed perhaps 4 or 5.
    The winner was a lightweight RC car that did as good a job as me on following the track, but at a faster speed.
    Third place was an...
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    Money Pit V for Victory

    I placed 2 of 20 at the local "autonomous mini-cars" meetup/race today!
    The main limiting factor is the power of the motors -- they're geared 50:1, and if I gear them up more, they end up...
  17. Self-navigating rover, and how to ruin an AX-12A

    Saturday, there's a race in Oakland, with a track made from yellow intermittent centerline and white solid sidelines.
    (You're allowed to go past the sidelines.)
    This is indoors, and the track is...
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    Question(s) Re: Is EX 106+ servo still available?

    Yes, this is certainly a possibility, depending on how the system is assembled.

    The MX series servos use a 4096 position resolution absolute encoder, with a maximum absolute error of less than...
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    Re: Home network....

    TV just takes time away from building robots, anyway.
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    1,299

    Re: Home network....

    There may be something wrong with the wiring, or the connector on that particular wire. Do you have a cable tester? Or, can you get a 100 foot Ethernet cable and run around the place, and compare to...
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    Re: OpenCM 9.04 eeprom write problem

    Uh... it's been a while :-)

    If you read the support library, there are two functions that matter, that come from the lower-level flash control library for the MCU:

    1) Clear page
    2) Write to...
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    1,003

    Re: OpenCM 9.04 eeprom write problem

    A few years ago, I ended up trying to fix the bugs in the EEPROM module, but instead just wrote my own based on the same ideas.
    For example, if I only need a handful of different value keys, and...
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    700

    Re: USB2AX firmaware update

    Great -- sorry I missed it, and thanks for improving the indexing :-)
  24. Replies
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    700

    Re: USB2AX firmaware update

    Good to see you back!
    Do you have a Linux version of the bootloader loader? (Or is there another DFU loader that works there?)
    Windows 10 is much harder to install drivers on than Windows 7 :-(
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    Re: TTL bus has a mysterious pulse on it

    @KurtEck For the thing I tested, I was using the 5KP15CA, a 5 kilowatt bidirectional TVS. However, that diode wasn't needed in the end (as you can see in the picture, only electrolytic + ceramic.)...
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    Re: TTL bus has a mysterious pulse on it

    Four of these: Fixed Forever!

    https://watte.net/2017-07-23-vampire-pulse-solution-sm.jpg
  27. Replies
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    Re: TTL bus has a mysterious pulse on it

    I made a "capacitor plug" by cutting a TTL cable at an inch, and putting a 1 uF ceramic, a 100 uF electrolytic, and a 16V bidirectional TVS across the GND/power. I then plugged this straight into the...
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    Re: TTL bus has a mysterious pulse on it

    You know how a Dynamixel sometimes will pause in the middle of a reply for half a millisecond? (Presumably, the control loop interrupts)
    This happened while I was capturing, and the pulse is fairly...
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    Re: TTL bus has a mysterious pulse on it

    Oh, also: When I extend the return delay time register from 0 to 150 (which adds 300 microseconds of delay,) the pulses still show up in the response data, and never in the request data or the...
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    TTL bus has a mysterious pulse on it

    I have a rover. It uses four dynamixels to steer four wheels. (AX-12As)
    I have a Teensy and a 74HCT125 that talks to the Dynamixel bus.
    This largely works great. Except, once in a while (at...
  31. Question(s) Re: Advice and opinion about Phantom X for use in theatrical performance

    From the data you've given us, I would give it a 70% chance that you will have to cancel at least some performance, with the set-up you describe.
    This is not based on any kind of solid statistics,...
  32. Thread: UP Board

    by jwatte
    Replies
    33
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    8,693

    Discussion Re: UP Board

    Aluminum chassis + up2 might make for a good home theater PC. Or perhaps a 3D printer runner. (I have a little AMD-based Z-box from many years ago that initially went on the first Onyx walker doing...
  33. Thread: UP Board

    by jwatte
    Replies
    33
    Views
    8,693

    Discussion Re: UP Board

    Hate it when that happens! And I know exatly the smell you're talking about :sad:

    My favorite power protection is a PTC resettable fuse followed by a high-power TVS followed by a MOSFET or Shottky...
  34. Question(s) Re: Advice and opinion about Phantom X for use in theatrical performance

    Honestly, I think that, with the constraints you're suggesting, it's probably too much risk for your use case.
    If you could afford two robots so you have a "hot spare," that might reduce the risk.
  35. Replies
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    Re: OpenCM 9.04 eeprom write problem

    The STM chip on the OpenCM doesn't have "true" EEPROM memory. Instead, it has page-erasable flash memory. Page-erasable flash memory supports two operations:
    1) Set all the bits of a page to the...
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    Re: OpenCM 9.04 eeprom write problem

    "i" has a value range that can go way beyond the addressable range of the EEPROM library.
    (The EEPROM library is actually emulated by using flash memory.)
    You are writing too much to the EEPROM,...
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    News/Announcement Re: The Robotis TurtleBot3

    This error means one of a few things:

    1. The tools for this board are not correctly installed.
    2. The tools for the board are installed in the wrong Arduino version.
    3. There are also other...
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    Re: Numa V2 - Quad Mech

    Celebrating progress is what it's all about -- nothing's ever "finished" anyway :-)



    Can you upload compiled pyc/pyo files? If so, python -O will strip the comments.
  39. Question(s) Re: Advice and opinion about Phantom X for use in theatrical performance

    You can actually carry up to 160 Wh, but are limited to a maximum of two batteries in the 100-160 Wh range.
  40. Question(s) Re: Advice and opinion about Phantom X for use in theatrical performance

    In the US, the rules are that you either carry a battery as-installed in a factory-made device in checked luggage, or you carry spare batteries in your hand luggage. There's a maximum size for spare...
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