3178 2023 LEGO Robot Showcase: LITTLE MAC

Every year, I create a LEGO robot using Mindstorms EV3 (now sadly discontinued). This year, I was compelled by some of the things I saw at Week 0 to create this monstrous machine.

Back View

Front View

Side View

I was also inspired by some robots from 2018 that used the 180 degree rotating arm to place cubes. It was a bit of a challenge to balance out the extending claw because usually Ev3 motors with a 5:1 gear ratio can’t lift up 190 grams of pure LEGO and motor. On the back as a “counterboom”, I used a roll of nickels and some tape to secure it down. It can place both squishy cone and cube (I am working on 3D printing actual field elements and game pieces for it).
Underneath, it uses traditional LEGO tank treads and 2 Ev3 large motors to power 4 wheels on the underside (front and middle). For the rear wheels, I removed the tires off of some wide 56mm diameter wheels for easier turning.
The arm is powered up and down by 4:1 large motors and rotated by 5:1 large motors with the “counterboom” I mentioned earlier. The 2 medium motors drive the claw (4:1 gear ratio) and the extension of the arm (1:1). It uses 6/8 possible motors, and 2 infrared sensors to receive commands from the controller. I am looking into adding a camera to the front, and possible creating a drive station out of my controllers.
Some flavor of reveal vid will be up soon! Also feedback is appreciated.


If you are 3d printing custom gears, go big! You can make any diameter you want. Adding holes for pinned connections would give them more utility for future builds, too.

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Excited to see this bot in action! What events are you competing in? lmao

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It may or may not show up at UNH district event, North Shore district event, NEDCMP, and maybe Houston (if I can smuggle it on the plane)



This weekend I realized that the original version of this robot wasn’t quite what I wanted it to be. So I carefully removed the top and arm of the original robot, and in about 10 total hours, I built version 2 of Little Mac.

This robot features multiple new things, including:

  • Fully articulating 360 degree wrist on the end of arm
  • Passive “Punch Out” boom that shifts forward and backward with the weight of the intake arm as it moves (near the point where the motors are mounted has rubber bands applying force on both sides, allowing it to return to a centered position)
  • Intake that can grab both cones and cubes
  • Arm can reach to the high cone and cube nodes
  • Preferred pickup from double substation
  • 3D printed gears that I will need to replace with LEGO branded ones #qualiteeaward

I hope to bring this guy to various offseason events and possibly even run it on the carpet a few times to see how it goes (not in an actual match hopefully).

Inspiration was taken from teams like 176, 4253, 971, and 2471.


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