So frustrating. This FSR setup doesn’t work like I imagine it to be. It would crashed the bed so hard to trigger the sensor. I want it to lightly tap the bed and triggered.
Now if I lightly push the holder in front of the FSR holder, it would triggered instantly. So sensitivity is not an issue here just the force transfer isn’t optimum enough…
Back to drawing board
Is the hotend just bolted or spring loaded. If the hotend is rigidly mounted how is that lever being pushed?
No spring just the two screw holding it. Was hoping the canteliver arm would provide enough force to trigger the FSR but I was wrong
I like the idea, but maybe put the vertical, between the mounting bolts? Another idea is to preload it, the fsr would already have some force on it, then you adjust the sensitivity.
Keep trying, I think it can work.
thanks not giving up just yet. next I’m going to try two FSRs. one for each bolt directly perpendicular and on top of the bolt aaand we’ll see if that works
If the hotend is rigid with no play it may be difficult to get a good trigger without some serious force.
Yes apparently that’s exactly what I’ve discovered here…
you want a rigid hotend for the most part, but a precision hinge that allows no other movement can be controlled with a spring so there would be no X or Y wobble and the Z doesn’t move fast enough to worry about. hinge it against the FSR so it pivots into it, you will have a negative Z trigger height but the firmware should be ok with understanding that at getting the readings it needs for bed leveling, pretty sure but not positive on the neg Z value as I dont use FSR. that must be how it works though eh? I mean, its touching the bed that cant be a positive z offset… ?
I think that would defeat the purpose of using FSR in the first place. FSR can work with some amount of preloading and this is the tricky part that I will be spinning my head around next.
with a tuned in preloading, the goal would be, a light tap on the the nozzle to the bed would trigger the FSR. I hope this can be done. but my first couple attempt so far has failed.
Ah but if the FSR is too sensitive to even the lightest tap then you might find you get false triggering during carriage movements while calibrating from vibrations.
@Alex_Skoruppa I believe you’ve played with FSRs?
Thanks for chiming in Alex I knew you did something with FSR but I wanted to try non detachable and no offset method. It seems this would be the best way of integrating FSR sensor of done correctly
I think the force needs to be applied parallel to the bed. Essentially you are taking the normal force applied from your bed and using it as detection. By turning it at near 90 degrees, you’re cutting away a good bit of that force. Positioning it so that the hotend can lever on one side a little to hit the FSR should solve the problem in theory.
Agreed 100% @Griffin_Paquette
Regarding 2nd stage home speed, how would the printer know that it almost reach the bed and slow the speed… I heard about this feature but never quite understood how it works
@Step_Cia what about reverse homing. E.g home to the bottom and then you know how far approximately you are from the nozzle then just move up that amount.
Look at how the lulzbot mini works. It homes at z-max, then lowers and searches for zmin.
Ok I get it. Using z max limit make sense. Thanks
