Kossel Mini with FSRs under a heated bed

Hello. I am building a Kossel Mini with force-sensing resistors (a set of FSR402s) beneath a heated bed. I was hoping to use this configuration to allow the printer to auto-level itself.

I'm finding that the weight of the bed on the FSRs causes z-min to trigger. I attached a multimeter to measure the resistance of the FSRs and found that when there is no weight on the FSRs, the resistance is infinite (beyond what my multimeter can read, anyway). However, with the bed (and heated) on it, the FSRs show a resistance of around 10 kiloohms.

I can think of a couple of options to resolve this off the top of my head:

1. Is there a way to set the sensitivity of the z-min endstop so that at 10 kiloohms (or some other threshold), the endstop is still considered open?
2. Are there any good mounting solutions for the endstops that might reduce the load on the FSRs?
3. Should I use a different kind of sensor (such as a switch mounted to the effector)?

Thank you!

please read the wiki page on FSR [reprap.org]

I think most people who use FSRs under the bed use the JohnSL board to interface them to the microcontroller. Alternatively you could try connecting a resistor or potentiometer between the Z min endstop input and +5V. A 10K potentiometer or 4.7K resistor should be about right.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thank you both for the help. I hadn't heard of JohnSL boards, and I missed the detail on that page about potentially requiring a microcontroller. I think I will pursue this route, either by getting one premade or trying to assemble one myself.

One thing I was also a bit curious about is if there's a preference between using an analog or digital pin for the FSRs. Currently I have the FSRs connected in parallel into the zmin input on my RAMPS board. However, that page mentions that one of the analog inputs can be used instead. However, when I tried this, I could not figure out which configuration option to set in Configuration.h so that Marlin could treat the input as an endstop.