Building Sumobot Jr., No Soldering

Build instructions for Sumobot Jr., with no soldering required.

View on Github.


These instructions will help you build a Sumobot Jr. Here are some photos of a completed bot. (This bot is slightly different from the one in the construction photos - it's cut from acrylic and has soldered leads from the motors.)





  1. Start with 2 screws, a "horn" from the servo bag, and a Sumobot wheel.

  2. Check the alignment of holes in the your servo horns to the hole in your wheels. Be sure to screw into holes that will line up later.

  3. Screw one screw into each side of the servo horns. Don't be afraid to muscle them in there; you're drilling the threads as you go.

  4. Drill until the screws' tips just come out the flat side of the horn.

  5. Use the tips of the screws to line up to holes on the wheel. While pressing the horn towards the wheel, screw until tight.

  6. Alternate which screw you're working on every so often to keep it even.

  7. Make a second wheel and horn.

  8. It's normal for the tips of the screws to stick out the back of the wheel just a little.

  9. Get the traction-enhancing rubber bands for the wheels.

  10. Use the band to circle the wheel perpendicularly.

  11. Then rotate the band onto the wheel and coax in into place.

  12. (On laser cut pieces, arrows point towards the front of the bot.)

    The bottom of the bot chassis is the largest of the rectangular pieces. Note that it has 2 circular holes near the front.

    The sides are the 2 pieces with large rectangular cutouts and one slanted side towards the front.

    The top of the chassis is the smaller one with 4 circular holes in it; the weird off-grid hole is the front.

    The front of the chassis (aka the shovel) is rectangular with just two rectangular holes in it.

    Slide the bottom piece into one of the sides, making sure the front and back edges line up.

    Insert the top into one the first side piece, then slide the final side on.

    Slide the front piece onto the front.

    At this point, you can glue (Elmers, wood glue, super glue) and clamp the pieces together and let them sit for a while, or you can keep going unglued. Just don't keep working with wet glue.

  13. Insert the two servos into the chassis box, so that their posts stick out the sides of the bot. Insert the zipties into the holes just behind the servos so that their locktabs point backwards.

  14. Wind the zipties back up through the bottom of the chassis, around the servos, and back through the locktabs. Tighten them. Now their tails stick out the back of the bot along with the servo wires. (Think about how you can decorate these when your bot is done.)

  15. Instead of cutting wires and soldering, we'll use jumper wires to connect the servos to the Arduino board. Get 6 small to medium jumper wires; 2 each of white, black and red is a nice convention, but all wires work the same. I was out of red wires, so I used orange ones.

  16. Put the breadboard onto your sumobot.
  17. Plug the jumper wires into the the connectors on the servos: white to white, black to black, and red to red (orange).

  18. Screw the ball-bearing holder into the bottom of the bot, into the holes near the front. Put a ball bearing into the holder; I used a marble here.

  19. Put batteries into the holder, and slide the battery holder into the back of the bot, with the wires hanging out.
  20. Screw the Arduino board onto the top of the bot.
  21. Using jumper wires if needed, connect the battery pack's red lead to +5 volts (probably pin 9) on the Arduino. Connect the battery pack's black lead to 0/Grnd on the Ardiuno.

    Sumobot Jr Wiring Diagram
  22. For each servo, connect it to power (red), ground (black), and send the signal (white) to pins 10 and 11.
  23. Snap the wheels onto the bot.
  24. Give yourself a high-five - construction is done!

It's Go Time.

More About Sumobot Jr

More Bots