VEX Drawing Robot - Autonomous Image-Tracing Robot
timeline: 2026
tech stack: C++, VEX V5, Python, OpenCV, Path Planning
Overview
A VEX robotics platform repurposed into an autonomous drawing machine. Given any input image, the robot converts it into a series of pen strokes and physically draws it on paper using a custom pen-holder mechanism mounted to the drivetrain.
How It Works
A Python preprocessing pipeline takes an input image, applies edge detection and contour extraction with OpenCV, then converts the contours into an optimized sequence of waypoints using a nearest-neighbor path planner to minimize pen-up travel time. The waypoints are sent to the VEX V5 brain over serial, which executes them as coordinated motor movements. A servo-actuated pen holder lifts and lowers the pen between strokes, and odometry feedback keeps the drawing aligned across the full page.
Results
The robot reproduces recognizable line drawings from photographs, handling curves, fine detail, and large fills. Draw time depends on image complexity — simple logos take a few minutes, detailed portraits up to fifteen.