The Radial Tattoo Plotter (RTP) is a capstone mechatronics project featuring an embedded system that controls a cylindrical manipulator to draw custom tattoo designs. The system scans a user’s arm to generate a 3D surface model, processes tattoo images to extract drawing paths, and projects these paths for precise application. The embedded firmware, developed for STM32, manages real-time control of stepper motors and coordinates communication between the scanning system and the host computer. The project highlights challenges in embedded firmware architecture, sensor integration, and reliable motor control. The prototype uses a pressure-controlled end effector to apply temporary tattoos with a washable marker.