Bed leveling with Force Sensing Resistor -> seems to work with simply "touching" the head to the bed. I think this is very intersting.

http://reprap.org/wiki/FSR

Yes, this should be possible - see [forums.reprap.org]. My suggestion is to put the force sensitive resistor in the x-carriage runner bearing mount, see the 5th post in that thread. I have designed my hot end board (see [forums.reprap.org]) so that with a firmware change and a component change, the ultrasonic sensor could be replaced by an FSR.

One disadvantage compared with ultrasonic height sensing is that the nozzle needs to be clean, since any extruded filament stuck on the end will cause premature contact.

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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].

>One disadvantage compared with ultrasonic height sensing is that the nozzle needs to be clean, since any extruded filament stuck on the end will cause premature contact.
I think I would like to try HEATING the nozzle and "cleaning" it on the bed. something along the lines of
- home x,y
- heat nozzle
- move to X5 Y5
- lower until "contact" is detected by FSR
- move 2-3mm
- if FSR shows "less contact" -> move z down "a bit", goto move
- else -> must be "really touching" therefore set Z=0

really wondering if this could work...

nophead (in his early days) used a discarded electric toothbrush head as a wiper and used it like that I think

Ray