How to prevent sled from ripping the ring apart when it goes too far up

I’ve noticed a lot of people accidently rip their maslow ring apart. Is there a cheap sensor less than $15 that can prevent this by shutting down the machine? I was thinking garage door optical sensors put at the very top of the wasteboard so if the sled goes more than 10" above then it would trip the sensor which would be wired to the aux on the arduino to shut off the machine? good idea?

the metal parts of the ring kit only cost about $15 to get laser cut so it make sense to keep the sensor below that cost.

You could sell a red mushroom/panic/emergency-power-off button the user can smash to stop it…? I put light switches on my maslow and everything plugs into outlets connected to the light switches so it can all be shut off quickly rather than unplugged.

The M2 controller has a bad history of doing this when there is no machine home set. Some go up and some go down, but they will go even if just moving the z axis unless homed/reset chains first.

You are talking about a beam break sensor like the garage door eye? what if you accidentally put your hand up there while in the middle of a cut? You would have to add logic to the firmware to incorporate the sensor, so perhaps the root cause could be addressed in firmware? The assumption could be that the chains are extended at the center point rather than at full extension since manually mounting the sled will put it near the middle anyway. Before calibration, we need basic movement, so having the system set to think the sled is in the middle would be a reasonable starting assumption. Thoughts?

yes breaking the garage door beam by accident could happen and be frustrating. I will probably just include an emergency stop button. they are cheap in bulk and not too hard to wire up.

If the problem can be solved via firmware that would be great. I’ve never had this issue with our kits so not sure when the issue happens most often. I’m guessing at the beginning of a cut.

Perhaps a check for no, or insufficient, movement from the encoders?