Hardware Required

You are going to need a few items to get a Head Tracker working

Boards

Here are boards this project will support,

Arduino Nano 33 BLE
- LSM9DS1 9 Axis, Gyrometer, Accelerometer and Magnetometer
- 2-4s Input Voltage (21v Max)
Arduino Nano 33 BLE Sense (Obsolete)
- LSM9DS1 9 Axis, Gyrometer, Accelerometer and Magnetometer
- 2-4s Input Voltage
- APDS 9960 Proximity sensor that can be used to reset zero
Arduino Nano 33 BLE Sense Revision 2
- BMI270 6 axis, Gyrometer & Accelerometer
- BMM150 3 axis, Magnetometer
- 2-4s Input Voltage (21V max)
- APDS 9960 Proximity sensor that can be used to reset zero
- This is a very nice Gyrometer chip, it's very stable in no-magnetometer mode.
DTQSYS Head Tracker by @Lele
- MPU6500 6 axis, Gyrometer & Accelerometer
- QMC588s 3 axis, Magnetometer
- 2-6s Voltage Input. (36V max)
- Beeper (There is no code to make use of this yet, it only beeps on startup)
- Battery Voltage can be monitored on Analog 0
- 3 Analog inputs
- Center button, pre-installed
- 3.5mm PPM jack, direct connect to radio
- 5V BEC on board, so you can power a ELRS transmitter for some truly good wireless trainer. See ELRS Setup
- PPM overvoltage signal protection on output and input. Not reverse polarity protected.

Ready to Go Kits

There are two suppliers who sell the pre-built kits with a Nano 33 BLE.

Nano 33 BLE - Build it yourself

The Nano 33 BLE + Nano 33 BLE Sense are now both obsolete. Their replacements are Nano 33 BLE Rev 2 and Nano 33 BLE Rev 2 Sense !!! There are issues with the code in v2.2 on these boards. It's not reliable. Please see Discord #test-firmware or GitHub actions for the most recent updates. We need more feedback on the state of this code. Thank you.

There are two variants of the Arduino Nano 33 BLE. The "Basic" one and the "Sense" version. Both have identical PCB's but the Sense has additional IC's installed. The proximity sensor on the Sense version can be used to reset the center instead of a physical switch.

If you have no intention of using the proximity sensor, buy the cheaper BLE board.

These boards are available from many sources. You can use the Octopart Search. It will show many suppliers stock, updated regularly:

https://octopart.com/search?q=ABX00030 (BLE version without headers)
https://octopart.com/search?q=ABX00031 (Sense version without headers)
https://octopart.com/search?q=ABX00034 (BLE version with installed headers)
https://octopart.com/search?q=ABX00035 (Sense version with installed headers)
https://octopart.com/search?q=ABX00069 (Sense Revision 2)

If you buy a Nano 33 BLE boards with headers pre-installed and want to remove them.

An easy way is to use a set of flush cut snips and clip off all the pins and remove the plastic bits from the bottom side. You will now only have short pieces of pin remaining. Heat one pin at a time from the top side of the board until it's loose, while holding it in your hand above a table. Smack your hand on the bench and the pin and solder will be ejected out downward leaving a nice clean hole.

DTQSYS Head Tracker

This board is purpose built for a Head Tracker by @Lele (Discord). You can find them on AliExpress or Banggood.

Where to purchase it,

USB Cable

The Arduino Nano 33 BLE board uses a Micro-AB connector. This means that the following 2 types of connectors will fit:

Micro B cables can be found at many stores. Computer stores, electronic suppliers, gas stations, etc. A very common.

Micro-A cables are less common, an example here: https://www.digikey.com/en/products/detail/cnc-tech/102-1072-BL-00200/3064850.

Push Button Switch

This is not required with the ready to go kits or

You will want to be able to line up the camera with the way you are facing. This is done by resetting the center with a button. If you bought the "Sense" version of the Arduino Nano 33 BLE then you can use the proximity sensor instead. Any normally open push button will work. Photo below is an example of a small tactile 6x6mm one.

RC Radio

It must support Trainer input functionality (PPM, SBUS or Bluetooth). Most radios support trainer using PPM with a 3.5mm head phone connector. Please refer to your manual for functionality and proper connector.