FugLong/Nano33_PC_Head_Tracker — reverse-engineered prompt

Build me a simple Arduino Nano 33 BLE head tracking project for PC games that works with OpenTrack. I want to attach the board to my headset, plug it into my PC with USB, and have it send head movement so games like Star Citizen can use it for looking around.

Please make the firmware for the Nano 33 boards with the LSM9DS1 IMU, include calibration on first connection, and use clear LED colors so I know when to keep it still, when to rotate it, when it is connected, and when calibration data is being reset. It should be practical for a beginner to flash and use, with a simple example sketch, setup notes, and OpenTrack configuration steps.

Keep the first version focused on reliable USB serial support. If Bluetooth is easy, add it as optional or leave clear notes for later. This old project says it moved to Azimuth, so look up the current docs online if you need to.