Cheap Tracker (SlimeVR)

The v2 version based on BMI160 and QMC5883L has been released. See the link below:
[SlimeVR] CheapTracker v2 - LCSC Open Source Hardware Platform (oshwhub.com)
 
Mini D1 (ESP8266) + BMI160 solution, solderable with just a soldering iron, allowing everyone to use full-body tracking at low cost. It maximizes low cost with a shell-less design. The downsides are that it's a bit heavy and large.
 
Component and material purchasing notes:
I purchased most components from Yongtaifa Electronics on Taobao, which cost approximately 20 RMB per Tracker (as of March 30, 2024). Pay attention to the package when purchasing; the TP4056 module is a Type-C protected module.
For lithium batteries, you can buy the cheapest 18650 type. It's not a big problem if the battery specifications are misleading or the battery has been disassembled (mine cost only 2 yuan per cell; the official documentation states 1 hour of battery life per 100mAh). Of course, if your budget allows, you can buy brand new, genuine batteries.
For the strap, I recommend using either a snap-on elastic strap or a Velcro elastic strap; a width of 3.8cm-4cm is fine. If you have one on hand, you can use that too, as the motherboard supports three strap widths (2cm, 4cm, 6.5cm).
 
BMI160 Calibration Notes:
With the strap side facing up, restart to trigger calibration mode. Due to the lack of a casing, when calibrating the six sides, you need to find six flat surfaces that are flush against the back of the motherboard. You can use a table, chair, wall, or other surfaces with 90-degree corners for calibration.
 
Charging Board Usage Notes:
When using the charging board, pay attention to the power supply wattage and voltage. It must be powered by a 5V power supply. For safety, it is recommended to reserve 1A of current for each charging port. For example, a 5V/3A power supply can charge a maximum of 3 Trackers simultaneously.
 
Soldering Notes: When soldering the motherboard, to avoid scratching the bottom strap with through-hole pins, it is recommended to solder all components on the front side, and then cut off the pins with diagonal pliers. Solder the battery compartment last.
The charging board uses 6 4-pin Type-C male connectors with boards, which are inserted through the back for soldering.
 
Firmware Flashing and Software Usage Notes:
Refer to the official documentation (the most detailed and complete) Introduction - SlimeVR Docs
or Bilibili, where there are many tutorials available.