LEGO MINDSTORMS Robot Inventor's Hub to Hub Communication Hacks

LEGO MINDSTORMS Robot Inventor's Hub to Hub Communication is implemented on Bluetooth LE (BLE) Advertising.

For example, when a hub transmits a signal named "ABC" with a value "123", some INVALID advertising packets will be sent as follows:

Data structure

FF 03 97 01 48 03 83 A3 31 32 33

Bytes	Meaning	Note
`FF 03 97`	Fixed header
`01`	Transmission ID (`0x00` - `0xff`)	MUST be changed for each transmission
`48 03 83 A3`	Signal name hash = CRC32(`"ABC"`) = `0xA3830348`
`31 32 33`	Value = `"123"`	Max 23 bytes

How to transmit a signal by hcitool

$ sudo hcitool -i hci0 cmd 0x08 0x0006 a0 00 a0 00 02 00 00 00 00 00 00 00 00 07 00
$ sudo hcitool -i hci0 cmd 0x08 0x0008 0b ff 03 97 01 48 03 83 a3 31 32 33
$ sudo hcitool -i hci0 cmd 0x08 0x000a 01
...
$ sudo hcitool -i hci0 cmd 0x08 0x000a 00

Ref. Bluetooth Core Specification Version 5.3, Vol 4, Part E, 7.8 LE Controller Commands

Transmit and receive signals on Raspberry Pi OS

hub2hub.py is a Hub to Hub Communication library written by Python 3.7x for Raspberry Pi OS (and Linux). Usage as command:

$ sudo python3 hub2hub.py transmit <transmission-id> <signal-name> <value>

$ sudo python3 hub2hub.py receive

Transmission Demo

https://www.youtube.com/watch?v=K0kwiPHDSnw
Transmitter: Raspberry Pi Zero W
- Python 3.7+ scrpit: raspberry-pi/transmitter.py importing hub2hub.py
- Transmit signals named "ABC" with a counter value when pushing the button like this word block program
Receiver: MINDSTORMS Hub

Transmit and receive signals on SPIKE Prime Hub OS

MicroPython v1.12 scripts for SPIKE Prime Hub OS 3.1.21.9

Transmitter program: spike-prime/transmitter.py
Receiver program: spike-prime/receiver.py
TODO:
- implement crc32()

Transmit and receive signals on ESP32

WIP