Open CG-Scale

The complete project is open source.

The weight and the CG is measured by 3 scale modules places under the landing gear of the airplane. Everything is powered by an ESP32. The position of the CG is projected by a laser on the button of the plane.

Measuring of distance is supported by a laser, that points to the middle of the main gear.

All information are shown on a Android app via bluetooth 4.0 low energy. The app was designed in Thunkable. The design file is stored together with the aplication AKP in the repo. (Link)

All parts are printed 3d. Files are provided as (STL). Some aluminium parts are required. But they can simply be cutted from aluminium profile (PDF).

Hardware

Based on ESP32.

• Used Board ESP32 WeMos LOLIN32 Lite V1.0.0
  • https://wiki.wemos.cc/products:lolin32:lolin32_lite
  • https://arduino-projekte.info/wemos-lolin32-lite/ (German)
• The Board provides an Lipo Battery Charger

Scale

• Used 10 kg load cell together with the HX-711 board you can find for example
  • on ebay: https://tinyurl.com/ybxn4rfh
  • on aliexpress: https://tinyurl.com/y78dd9gv

Laser pointer module

• From ebay like https://tinyurl.com/y8mcnznn
• Aliexpress https://tinyurl.com/ydeltejj

Used Libaries

• Used Libraries from espressif. See https://github.com/espressif/arduino-esp32/blob/master/docs/arduino-ide/boards_manager.md for installation.
• HX-711 Board: https://github.com/bogde/HX711.git

Circuit

The PIN-setting to the esp32 is configured in the config.h file.