RP2350 Ethernet Servo Controller

A web-based servo controller for the Raspberry Pi Pico (RP2350) with Ethernet connectivity using the CH9120 Ethernet module. https://www.waveshare.com/wiki/RP2350-ETH https://www.amazon.com/dp/B0C3R86WFB?ref=ppx_yo2ov_dt_b_fed_asin_title

Overview

This project implements a web server on the RP2350 microcontroller that allows remote control of up to three servos (tilt, zoom, and focus) through a simple web interface. The system uses the CH9120 Ethernet module to provide network connectivity.

Hardware Requirements

• Raspberry Pi Pico (RP2350)
• CH9120 Ethernet Module
• 3 Servo Motors
• Power supply for servos
• Jumper wires

Pin Connections

CH9120 Module

• TX: GPIO20
• RX: GPIO21
• CFG: GPIO18
• RST: GPIO19

Servo Motors

• Tilt Servo: GPIO2
• Zoom Servo: GPIO3
• Focus Servo: GPIO4 -- Yaw Servo (external): GPIO5

Features

• Web-based control interface
• Real-time servo position adjustment
• Persistent storage of servo positions
• Support for three independent servos
• Simple HTTP API for integration

Web Interface

The web interface provides sliders for each servo with the following features:

• Range: 1000-2000 μs
• Real-time position updates
• Numeric input option
• Automatic position saving

API Endpoints

• GET / - Serves the web interface
• GET /set?{servo}={value} - Sets servo position
  • Parameters:
    • servo: tilt, zoom, or focus
    • value: position in microseconds (1000-2000)

First hardware usage - Setup

1. Connect USB-C cable from computer to module
2. Push and hold boot and reset buttons, then release reset, then release boot. A file volume will appear on your OS.
3. Drag and drop rp2-pico-20230209-unstable-v1.19.1.uf2 to the drive that shows up. The board will restart and the file volume disconnect.
4. Install mpremote: pip install mpremote

Setup

Make sure to setup device with RPI_PICO-20250415-v1.25.0

1. Flash the RP2350 with the provided firmware: mpremote cp main.py :main.py and mpremote cp ch9120.py :ch9120.py
2. Connect the servos according to the pin connections
3. Power on the system - if debugging, run main.py with mpremote run main.py (otherwise main.py runs on boot)
4. Access the web interface at http://192.168.2.42

Dependencies

• MicroPython for RP2350
• CH9120 Ethernet module driver

License

This project is open source and available under the MIT License.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.