Try to connect to LEGO HUB

Hi @kawasaki, I have got a LEGO HUB from the LEGO Mindstorms robot inventor set. I am not sure if it should connect aswell using the scratch_link script. Is it compatible with LEGO HUB? I managed to pair the LEGO HUB using bluetoothctl:

pi@raspberrypi:~ $ bluetoothctl
Agent registered
[bluetooth]# devices
Device 38:0B:3C:AD:54:5F LEGO Hub 38:0B:3C:AD:54:5F

Output from scratch_link:

pi@raspberrypi:~ $ /home/pi/.local/bin/scratch_link 
2021-01-03 15:34:12,556 FireFox NSS DB not found. Do not add certificate.
2021-01-03 15:34:12,616 Certificate is ready for Chrome
2021-01-03 15:34:12,659 Started scratch-link
2021-01-03 15:34:17,185 Start session for web socket path: /scratch/bt

But Scratch is not finding the device. (“No devices found”). Is the LEGO HUB equal / compatible to LEGO MINDSTORMS EV3? Thanks for your support 😃 Best regards Andy

[kawasaki]

@rasenderhase Thank you for sharing the debug log. Though it does not clarify everything, it is definitely helpful. I found two things from it.

1. After the first “loop in BT thread” message, I expect the message “in discovery: state”. But it is missing. Session.status may have unexpected value.
2. While I walked through the debug log, I noticed that my code tweak for LEGO Hub was not enough. I modified the handling of device class returned from the device. On top of that, I needed to modify the device class used for device discovery API.

For these two findings, I made another commit 3cf61a145b3a in the dev branch. It adds more debug print to track session status and discovery work, and add one more code tweak for LEGO Hub.

Can you try the dev branch tip? (I expect that I will need to ask you some more trials based on the results.).

[kawasaki]

@rasenderhase Thank you for the info. LEGO HUB has the device class numbers 8 and 4. I will teak the pyscrlink code to make LEGO Hub pretend to be LEGO EV3 (class numbers 8 and 1), hopefully on next Sunday 😃