Study of the LEGO WeDo 2 BLE protocol at the byte level.
This was carried out using a BLED112 dongle, however the data can be used in any app that can write byte data to a UUID.
The official SDK is at https://education.lego.com/en-us/support/wedo-2/developer-kits
However sometimes its just easier to write a few bytes directly to a UUID!
Hope it's of some use in your project.