Monthly Archives: December 2018

What Do I Want in a Robot? Part 1

End of an Era

I’ve been having a lot of fun playing around with different technologies. I enjoyed unguided dabbling in realms all the way from the battery to the web-based UI. It is thus, with reservation, time to acknowledge that I must move on.

What do I really want to do? I thought it was build a robot. I did that many times. I was wrong. I want to be able to more robots, quicker and cheaper than I do now. I also want it possible for anyone with a 3D printer to build.

Skills Necessary to Pay Robot Bills

I want one of these robots to be able to be built by any random kid. I got my first soldering iron around 12 years old, so I’m going to shoot for that level. However, I would not expect the kid to be able to do much more than assemble it. For programming it with new behaviors, I’d expect that’d take to around 15-16 years old. Once again, that’s when I started getting more comfortable with programming small projects.

As for tools and materials, here’s an abridged list:

  • 3D printer
  • Linux computer w/ a nice screen, keyboard, and mouse
  • Screwdriver (assorted or a kit)
  • Pliers, tweezers, etc.
  • Calipers (digital and semi-accurate)
  • Battery charger
  • Lots of unguided free time, like I did

The rest is consumable goods and other parts.

Building Robots with a Grain of Salt

While not all parts are known yet, here’s an overview of the constituents.

  • Processing
    • Raspberry Pi 3 or above — Used for processing of video, streaming video, and all heavy lifting.
    • Arduino Micro — These Arduinos are tiny and have a plethora of IO ports. Perfect for hooking up motors and sensors.
  • Sensors
    • PI compatible NoIR camera — Night vision is important, as pets with dark fur could otherwise evade detection.
    • Range finders × 8 — We got the IO ports on the Micro, why not use them? I like Pololu’s Sharp analog distance sensors. They work well, have a flat beam that makes it possible to mount at or near the same level of the wheels.
  • Locomotion
    • Stepper motors × 3 — I started off with NEMA 17s with a good amount of torque. My suspicions are that I can drop to NEMA 14s, and with the reduced weight not need as much torque.
    • Omnidirectional wheels × 3 — I swear by the Vex IQ 63mm omni wheels. They’re affordable and easy to make a custom hub to attach to any motor.
    • Stepper motor drivers × 3 — I’m a fan of Pololu’s DRV8834 driver. It allows me to use the same power rail for the drivers and Arduino, which are on the same board. A few beefy capacitors in key spots, and it seems to work rather well.
  • Miscellaneous
    • IR illuminator — One of the circular ones designed for outdoors works well. Usually you can poke the PI cameras right through the center.
    • 7.2V battery — I got a Rage RC 5000mAh NiMH battery. It does the trick. This is only the second battery I’ve needed to buy in years, so I have little experience with these other than: they work.

Godspeed You! Robot Emperor

With these goals and ideas in mind, off I go to design what I hope is a robot so cool, it will inspire people. Failing that, it will terrorize my cats. I can live with either outcome.