Everything I've read about the induction sensors we use with 3d printers says that they're 'generally' meant to read thick steel, and that they can be a bit 'less sensitive' to the relatively thin aluminum used for build surfaces. The SN04-N sensor that came with my printer always sensed real close to the build surface - probably 1-2mm off of it. I was doing some searching, looking into sensors out there, I picked up a Taiss 'LJC18A3-H-Z/BX' that's supposed to be good for sensing from 1mm to 10mm. I thought 'great, with an adjustable sensing distance up to 10mm, this sensor should be able to be used with a piece of glass between it and the build plate. Well, it seems to work, but not quite how I expected.
Apparently this sensor is a CAPACITANCE sensor, not an INDUCTANCE sensor, and as a result, it can sense things other then metal. After I put it in place and set the 'home' position high enough off the aluminum build plate to allow a sheet of glass to slide under the nozzle so it wouldn't crash into the glass on homing, I was a 'bit' surprised to find that when I re-homed it, it homed higher, as in it was homing off the glass, not the aluminum.
This seems to be a bit of a win for bed leveling when using glass as a build surface... Is there any reason not to use this kind of sensor over an inductance sensor?
