Chris, I thought about optical sensors, etc., but the slack detection was so easy and had a lot of room for "slop" while still accomplishing the goals.
#1 was a non-starter, that would be VERY expensive for the size stepper motor needed and the control circuitry needed to manage it. We're taking at a minimum hundreds of dollars and a ton of development work! That sounds like killing flies with a sledgehammer!
#3 I'm having trouble visualizing exactly how that works or solves my problem. The issue is the table settles into place, but not necessarily all corners at exactly the same time. There is a certain amount of "wobble" as it goes up and down. Not much, but if you are looking, it's noticeable. It sounds like this sensing would share the issues of the current system, I wouldn't be positive that the table was fully seated.
The upward stop was never a problem, that's a totally non-critical adjustment. It's the lower stop that's the tricky one. When the table is coming down, it's the motion of the table that trips the limit switch. However, once the table hits the lower stops, it stops moving. If the switch is not precisely adjusted, the table stops just before it's totally down. However, once the table finally is totally down, if the switch doesn't trip simultaneously with that happening, then the motor keeps running as the switch will never trip, no movement after the table is all the way down! My mod makes sure the table is fully down, and only after that there is a positive action that opens the limit switch and stops the motor. I can't imagine a simpler method of doing this, and this should be dead reliable.
Steamfan77 posted:John, can you post a video of the new set up in action?
Once I get my flexible rubber cable and run it, I suppose I can. However, it'll look exactly like it runs now, the only difference is how the stop is triggered. Actually getting a picture of that action would probably be somewhat difficult.
