Just wanted to start a new thread when I found this one. Still, since I took some pictures, I guess my post is worth something after all 
Took the freedom to make the title a bit more dramaticâŠ
TL;DR;
When the machine starts up, it assumes door state âclosedâ regardless of the actual door state. Only after closing the door properly once, the door state by e.g. M1010 reflects the physical door state.
This is a security problem when because of e.g. misaligned magnets (like after them falling off [again]) or a broken cable or connection the door sensor reports back âopenâ constantly. In this case the machine will never switch to âopenâ in its software, and if you then open the door mid-laser-job, it will not interrupt it, thus rendering the safty feature useless and putting your loved ones in danger.
If you want to verify this: Boot up your machine with at least one door open. Connect to the machine with Luban (either serial or network) and issue M1010. The answer will be Door State: Closed. Close all doors and open one again - M1010 will show Door state: open.
Iâm on 1.13.2 (and currently reluctant to upgrade) - would be nice if someone on 1.14.1 could test it there!
Long story:
I was running a laser job and could not properly see how it was going, so I put on my goggles and opened the door to take a closer look. After sticking in my head I though: How stupid, this will interrupt the laser job - but actually it did not. I checked the door detection setting, and it was active - so wtf?
I checked with Luban and M1010 and always received Door state closed. OK, I thought, the door sensor must be broken. I disassembled it - it is actually a nice bit of engineering: They included four hall sensors and four LEDs to check if the hall sensors register a magnet - made troubleshooting easy!
Hereâs the four sensors (left) and LEDs (right):
And here it is in action, showing the door magnets registered of one door:
Turns out that my magnets were misaligned. They kept dropping off all the time (like many others had it - at least with the Kickstarter version - see also this thread), and at some point I used superglue to fix them for good. Past then, door sensor worked fine. Yet it seems to be a borderline case - now my workshop being colder in winter, only three of the four magnets registered, and the switch reports âopenâ even if just one hall sensor is âoffâ. The LEDs made it really easy to spot the problem and to realign the magnets.
So technical problem solved, but firmware bug remains. Iâll file a bug report on this.