Final project: PLOT BOT V0.1

presentation

1. Concept

Mecanum wheeled pen plotter with infinite* plotting area: This project is a mobile pen plotter that uses Mecanum wheels and can draw on surfaces much larger than its own size (*currently limited by wires though). The robot uses Pi Pico to receive G-code via serial, parse it directly, and control stepper motors on 4 Mecanum wheels and a Z-axis servo, with end-stop for zeroing.

2. Potential use cases

This machine can create large-scale drawings without being constrained by the physical size of the device. Possible applications include drawing large calligraphy, drawing Nazca Lines, or perhaps for documenting as it goes (literally).

3. Background

The idea started from a simple curiosity: could a machine print or draw things bigger than itself? Traditional 3D printers are limited by their fixed frames. This machine moves freely in X and Y directions using omni-wheels, and could later add a Z-axis arm for height. In the future, it might even be able to climb onto its own printed objects and keep building—making truly large-scale 3D printing possible.

4. Technical overview

The robot interprets G-code and moves using four Mecanum wheels. A microcontroller (e.g., RP2040) directly runs motor control logic without standard firmware, allowing custom handling of omni-directional movement. Basic Z-axis control is handled by a servo. Future improvements include position tracking and wireless control.

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5. Next spirals

Add relative/absolute tracking for position correction
Enable wireless control and battery power
Improve Z-axis design for 3D printing
Incorporate 3D printing firmware
Add filament feeding system and extruder