Splain! Is this usable on other bots? Can we use it if there is glass on top of the metal bed? Can it detect just aluminum or unobtanium as well? Interested parties need to know!
https://printrbot.com/shop/auto-leveling-probe-2/
Lemme know what you find out.
No. 
It should work on just about any FDM 3d printer and any metal bed with reasonable level of conductivity should work. Not sure what kind of firmware setup would be required however if you’re not using Marlin and/or the pb firmware didn’t work for you.
thawkins has done a bit of exploration into other probes that you might find interesting also.
http://www.printrbottalk.com/forum/viewtopic.php?f=113&t=6812&p=44622#p44622
Thanx for the infos.
There are two kinds of proximity sensors. The conductive one we you are showing here, which relies on conductivity of the material that triggers the sensor. The other type is capacative. This type doesn’t need conductive materials to operate, but is more difficult to implement in a reprap machine, since every kind of material in proximity will trigger it.
I’ve seen people use switches as well. Mostly on deltas, which is why I found this curious.
do they have these in a small size? I ordered some for my zen toolworks cnc mill and they are big… too big to put on my print head