This project is an interactive, standalone CNC-style drawing machine powered by the ATmega328P microcontroller. It translates user inputs from a resistive touch panel or pre-loaded data into precise mechanical motion using NEMA 17 stepper motors. The system features a built-in UI displayed on an ILI9486 LCD, allowing the user to select between distinct operating modes via a potentiometer.

• Purpose: The primary goal is to design a versatile embedded system that handles multi-peripheral integration; specifically ADC processing for touch and analog inputs, SPI communication for external storage, and precise timing for stepper motor control.

• The idea: The project was inspired by the desire to build a simpler version of a CNC machine that can be easy to modify, operate and calibrate, but without compromising the features and complexity of the software.

• Utility: For the developers, it provides deep, hands-on experience with microcontroller peripheral management, memory constraints, and motion control logic. For users, it serves as an intuitive, tactile tool capable of assisting in drawing perfect geometric shapes or automatically replicating complex digital patterns.

Mini-Plotter is an automated drawing system based on the ATmega328P-XMINI. The system operates as a closed-loop interface where user input is captured via a resistive touch screen or an SD card and translated into physical motion through two NEMA 17 stepper motors. The project logic is divided into three functional layers:

• Input Acquisition: Captures analog coordinates (via Resistive Touch) and menu selection (via Potentiometer) or digital data (via SD Card).

• Processing & Control: The MCU executes state-machine logic to handle three modes:
  • Freehand
  • Shape Correction (algorithmic smoothing)
  • SD File Execution

• Output Execution: Real-time visual feedback on the ILI9486 LCD and high-precision motor control via DRV8825 drivers.

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