Robotic Arm
A custom-built robotic arm controlled with N20 motors and an ESP32, featuring a 16 to 32 tooth gear ratio on the base for precise rotation.
See it in action
Overview
A custom robotic arm built with N20 motors controlled through an ESP32 with a custom board. The base uses a 16 to 32 tooth gear ratio for controlled and precise rotation.
The entire arm is 3D printed. The second joint is driven by another N20 motor through a 1:1 pair of 24-tooth gears, and the claw is a custom two-gear mechanism powered by another N20. The whole build is press-fit - no screws or fasteners needed.
Hardware used
Handles motor control and command logic from a custom-designed driver board.
Compact DC motors driving the base, second joint, and claw mechanism.
Entire arm is printed - frame, gears, joints, and claw - designed for press-fit assembly.
16:32 reduction at the base, 1:1 24-tooth pair at the second joint, two-gear claw mechanism.
Mechanism breakdown
A 16-tooth pinion drives a 32-tooth ring for a 2:1 reduction. This slows the base down and increases torque, giving controlled, precise rotation instead of jerky movement.
Driven by another N20 motor through a 1:1 pair of 24-tooth gears. Keeps the joint compact while transferring motion cleanly without backlash.
A simple two-gear mechanism, custom designed and driven by an N20 motor. Opens and closes with consistent grip force.
Challenges & Learnings
Tuning the gear ratio
Direct-driving the base made it spin too fast and overshoot every target. The 16:32 reduction calmed the motion down and made positioning predictable.
Press-fit tolerances
The entire arm uses no screws - every part is press-fit. Getting tolerances right in CAD took several print iterations so joints stayed tight but still moved freely.
Custom ESP32 board
Building a custom driver board kept the wiring clean and the arm self-contained, but meant designing the motor control circuit from scratch.
Summary
A self-contained, fully 3D-printed robotic arm that combines custom electronics, careful gear-ratio choices, and press-fit mechanical design. It's a hands-on study in making a multi-axis system feel precise and intentional rather than hacked together.