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Robot base comments — Parallax Forums

Robot base comments

The two disk based bot design that Micro Center sells for Adafruit uses the same pair of gear enabled motors that were described by erco early on, (last sold when RS was going out of business), and in a base also sold by Tinkersphere as well. (Both are based in NYC). By disk based, I mean that the bases sold with the other parts are indeed circular in shape.

And it seems that both of the platform designers expects that the buyers will be using the Arduino platform to manage these motors. Obviously it is possible to manage such devices via the Prop. And indeed Parallax does sell comparable hardware.

Has anyone bought either of these platforms, and gotten them to work using the Prop, and appropriate motor driver circuits?

Just asking. No plans to build something around them. Certainly something around the kit that erco described, soon.

Comments

  • How large is the base diameter? Would you happen to have a link handy? Thanks!
  • Afraid not, but the Micro Center site should give you a good idea. Search on their site using the term "adafruit" w/o quotes of course, and it should be there, and cost about 20 dollars use.

    The more expensive one of the two is the Tinkersphere one. Look at their site on robots. And I suggest using Google to find both sites.
  • ercoerco Posts: 20,256
    I guess you mean: http://www.microcenter.com/product/474379/AdaBox002_Feather_Bluetooth_LE_Mini_Robot

    See also the chassis only for $19 at https://www.amazon.com/Feetech-FT-DC-006-SMC-Aluminum-Vehicle-FT-SMC-2CH/dp/B06XXS8L1C

    The $19 Feetech chassis includes a nice motor driver board which uses servo-style pulses to drive the two DC motors.
  • Basically yes.
    And as it happens, I did buy that particular kit. Twice as it happens. Then several other items.

    I'd say we are off to the races with everything.
  • ercoerco Posts: 20,256
    edited 2017-11-10 00:04
    BTW that chassis kit, when ordered directly from Feetech in China, comes with a choice of gear ratios (48:1, 120:1 and 256:1). I prefer the 120:1 ratio myself. I don't know what comes from Amazon (no choice AFAIK). These use midsize yellow Solarbotics/Vigor gearmotors. Here's my figure 8 with one.



    And another Feetech chassis doing a figure 8. This one uses gutted blue 9g (small) servos for gearmotors:

  • Um actually close enough. But I chose a different one.

    This one

    And that one is much the same as the cat chase toy described in the Amazon page. Yes after realizing that the bot kit is simply trying to chase them, the capable well dressed individual will turn around start chasing the thing.

    I first admit that I tracked down a copy of a book on PDA Robotics to better understand how to make things move. And of course that book on Linux and robotics. On his site, the author of that one admits that his ideas made sense years earlier. But now with the Raspberry Pi around, he's largely giving up on the book.

    Me? I bought it before I discovered the Pi, in hopes that I'd discover how to have the penguins talk to circuits other then their own. But that's a discussion for a different thread. And I believe again we've answered the correspondent's questions.
  • ercoerco Posts: 20,256
    The other one is also available at https://www.ebay.com/itm/2WD-Two-Wheel-Drive-Metal-Smart-Robot-Car-Chassis-Arduino-DC-Motor-DIY-USA/262454223855

    Both these kits are sold direct from the manufacturer for $6... but shipping is costly, so you have to order ten at a time to make it worthwhile. They're pretty nice kits but have some QA issues. If you order ten, you'll find a few defects.
  • erco wrote: »
    The other one is also available at https://www.ebay.com/itm/2WD-Two-Wheel-Drive-Metal-Smart-Robot-Car-Chassis-Arduino-DC-Motor-DIY-USA/262454223855

    Both these kits are sold direct from the manufacturer for $6... but shipping is costly, so you have to order ten at a time to make it worthwhile. They're pretty nice kits but have some QA issues. If you order ten, you'll find a few defects.
    That sounds highly suggestive! But I'm not a fan of that site. And the big problem I have right now is space. My family is grouching over what I do have out, and want me to defenestrate more.

  • Haha, that’s funny about the Pi disruption in the robotics field, but I think that's somehow missing the point. Linux is the future of robotics, so why give up on his book? (Though I have no idea what book you're referring to.)

    The ideal scenario I've got in my mind is something like a Pi or equivalent as the overarching "brain", passing computer vision and related tasks to something like an Nvidia TX2, and calling on a Propeller / Arduino level chip for motor, servo and sensor control.
    That would all be done under ROS . . . Linux.

    Those look like nice little chassis kits, but unfortunately a little small for what I'm working on next. Something the size of the Stingray or close seems about right to hold multiple battery packs and control boards.
  • Perhaps he is talking about the Doug Williams book on PDA Robotics, as in Personal Digital Assistant Robotics. However, that might be a good used of my old HP Jornada; to control some sort of robotic system with a Propeller. I did hack an old iPod and installed a Linux version on it some moons ago but not sure if it could control anything except a play list.

    The chassis look nice, but i personally try to avoid the direct purchase things from Chinese vendors and stick to the Major sources either in the US or UK. That's just me.

    As far as the RasPi being a disruption in Robotics, the ev3 for the Lego Mindstorm kit is an Embedded Linux device and has been out for sometime now but is a bit pricey. There are ports of the Ev3 code to the RasPi which offers a much cheaper option to the Lego system. The Pi and the BeagleBone (the BeagleBone Blue is really for Robotics) have offered a low cost option for folks to get into Linux and Robotics, so it has been interesting to see how these systems have push the evolution of Linux over the past few of years. Having worked with Linux since '96, it is nice to see it get some traction finally.

    If you have a Nvidia TX2 why would you need a Pi. I believe the TX2 is more powerful than the Pi and supports ROS on its own.
  • Sorry to hijack the thread, but @JonM - that's cool, I didn't realize the TX2 has its own quad ARM A57 as well. I thought it was just the Nvidia CUDA GPU cores after reading a quick news article about some MIT students using it for the vision side of a robotic car project. That's pretty sweet it has everything all wrapped into one. Hook that up to a Propeller for real-time control of motors and sensors, and that would make one heck of an ROS bot. :smile: I'm dreaming now...
  • JonM wrote: »
    Perhaps he is talking about the Doug Williams book on PDA Robotics, as in Personal Digital Assistant Robotics. However, that might be a good used of my old HP Jornada; to control some sort of robotic system with a Propeller. I did hack an old iPod and installed a Linux version on it some moons ago but not sure if it could control anything except a play list.

    The chassis look nice, but i personally try to avoid the direct purchase things from Chinese vendors and stick to the Major sources either in the US or UK. That's just me.

    As far as the RasPi being a disruption in Robotics, the ev3 for the Lego Mindstorm kit is an Embedded Linux device and has been out for sometime now but is a bit pricey. There are ports of the Ev3 code to the RasPi which offers a much cheaper option to the Lego system. The Pi and the BeagleBone (the BeagleBone Blue is really for Robotics) have offered a low cost option for folks to get into Linux and Robotics, so it has been interesting to see how these systems have push the evolution of Linux over the past few of years. Having worked with Linux since '96, it is nice to see it get some traction finally.

    If you have a Nvidia TX2 why would you need a Pi. I believe the TX2 is more powerful than the Pi and supports ROS on its own.

    Hello!
    About the PDA robotics book, no I am not. I'm talking about a different one. Yours I did read. A little too complicated. The book on Linux and Robotics had the author physically embedding a full feature PC motherboard into a system.

    I've also examined the Lego Mindstorms stuff, and how the third party companies have managed to create a RasPi alternative. As for the Nvidia TX2, ask me about that when it comes down to being below the cost of the Pi family members.

    Me as well. I'd rather buy my chassis directly from a supported US vendor. Besides I still have that tractor tread base that's waiting for a brain.
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