Arduino USB Media Controller

This project features a compact, custom-built USB HID (Human Interface Device) that enables tactile interaction with digital media through a rotary encoder. By bypassing traditional on-screen controls, this device provides dedicated physical inputs for volume adjustment, playback, and track skipping.

🛠 Hardware Requirements

To successfully build this project, ensure you have the following components:

• Microcontroller: OSOYOO R3 UNO (ATmega328P + ATmega16U2).
• Input: 1x Rotary Encoder with a clickable dial.
• Capacitors: A total of 100nF is required for bootloading. (e.g., three 30nF and one 10nF capacitors in parallel).
• Wiring: Jumper wires and a breadboard.
• Enclosure: 3D printed case and knob (see 3D Printing).

💻 Software & Firmware Installation

Standard Arduino Uno R3 boards do not natively support USB HID functions. This project uses HoodLoader2 firmware to reprogram the ATmega16U2 chip.

1. Required Libraries

Install these libraries via the Arduino IDE Library Manager:

• OneButton (by Matthias Hertel): Handles clicking logic.
• Adafruit Rotary Encoder Library: Manages encoder rotation.

2. Flashing the Firmware (HoodLoader2)

Reprogramming requires separating the microcontrollers into independently programmable units.

1. Suggest Method: Use the Installation Sketch method for a standalone Arduino Uno.
2. Wiki Reference: Follow the full Hardware Installation Guide on the HoodLoader2 wiki.
3. Stability: Ensure the 100nF capacitor is used. Capacitance values below 100nF will cause flashing failures.

3. Rotary Encoder Connection

Once the firmware is flashed, connect the encoder to the 16U2's serial interface data ports.

• Pins: The encoder requires 3 data pins (CLK, DT, SW) plus VCC and GND.

🖨 3D Printing & Assembly Tips

The enclosure consists of three parts matching the provided .stl files:

• Models:
  • Bottom Case
  • Top Case
  • Rotary Knob
• Slicing: Use software like Ultimaker Cura or PrusaSlicer.
• Print Reliability: Add a brim to ensure the case does not detach.
• Tolerances: The top part includes an extrusion to fit the base snugly.

🕹 Usage & Controls

Once connected, the device follows this logic:

Input Action	Resulting Function
Rotate Clockwise	Volume Up
Rotate Counter-Clockwise	Volume Down
Single Click	Play / Pause Toggle
Double Click	Skip Forward (Next Song)
Triple Click	Skip Backward (Previous Song)