Micro Mauler

Difficulty

Beginner

BYOB Kit

$20

Build Time

1 Weekend

Arena

Sumo · Combat

Overview

Hex Bugs, mini BattleBots toys, and dollar-store RC cars are cheap, small, and packed with salvageable parts. Strip the stock electronics, add Bluetooth control and upgraded motors, and you've got a micro-weight arena fighter that fits in your palm and punches above its weight class.

This is tabletop combat at its finest. Low cost, fast builds, and immediate gratification. Build three in an afternoon and host a tournament that night.

The Build

Strip the donor toy down to its chassis and wheels. Replace the stock motors and electronics with upgraded components. Add Bluetooth control and an optional spinning weapon. The whole build fits in the palm of your hand.

Remove the toy's shell, stock PCB, and motors. Keep the chassis, wheels, and battery compartment. Photograph the motor mounting before removal — you'll replicate the same geometry with the upgraded motors.

Hex Bugs use a simple vibration motor on bristles. For these, you're replacing the entire drive system. RC toys usually have geared DC motors that you can swap directly with the kit's micro gear motors.

Mount the micro gear motors using the original motor positions or the 3D-printed adapters. Wire them to the DRV8833 motor driver — this gives you full forward/reverse/speed control on both motors for tank-style steering.

// Bluetooth motor control
if (command == 'F') { forward(); }
if (command == 'L') { turnLeft(); }
if (command == 'W') { weaponOn(); }
// ... full implementation in project files
  

Wire the HC-05 Bluetooth module to the motor driver's control inputs via a small Arduino Nano or ATtiny85. Pair with your phone using the included control app. You get two virtual joysticks — one for driving, one for weapon speed.

Mount the spinning weapon motor on top or front of the chassis. The bar attachment spins at high RPM and delivers hits on contact. Clip the 3D-printed armor panels to the chassis — they're sacrificial and replaceable. Bring extras to competition.

Micro-weight class: 150 grams maximum. Standard sumo ring (12-inch diameter for micros) or open arena with walls. Matches are 90 seconds — most KOs happen in the first 30. Weapons allowed but no projectiles or liquids. Batteries must be secured and protected.