MouthPad^USB

After joining Augmental's creator program and receiving a custom-fitted MouthPad^, I built a BLE-to-USB HID dongle to solve real-world connectivity issues for MouthPad^ users on Windows and macOS.

The firmware turns the MouthPad^ wearable into a wired USB HID device. A microcontroller sits between the host computer and the MouthPad^, bridging BLE HID + Nordic UART Service traffic to USB HID + CDC without changing the MouthPad^ firmware.

Ships two platform implementations with identical USB interfaces: Nordic nRF52840 (production hardware on Seeed XIAO) and ESP32-S3 (feature parity alternative). Both expose the same HID descriptors, CDC command set, LED semantics, and bond-management behavior. Achieved 1:1 feature parity across 9+ board variants.

Also built companion desktop applications for macOS (Swift) and Windows (Rust/Tauri) for device configuration and management.