BLTouch is a touch sensor for the bed auto leveling. In 3d printing it is important to have level extremely well leveled otherwise the first layer would be layed properly and the prints would come off the bed. Until now the leveling has been done mostly manually by adjusting the height of the 3d printer bed before the printing.
the other option is to use a proximity sensor that is either capacitive, inductive or optical. All these types have a downside that they are not consistent with the different print surfaces and different thickness above the bed or the coulour (print) of the 3d build surface will produce different results. Every time the surface is being changed to different type the offsets have to be adjusted.
And then the BLTouch has been invented. It is a sensor that is mechanical and uses hall effect sensor. so the only moving part is the needle and since it can be retracted.
Because the needle can be retracted there is no more need for the servo mounted micro switches.
The BLTouch sensor is compatible with most of the open source 3D printer controller boards on the market. It requires only minor modifications to the wiring and to the firmware. Most of the 3d printers have already got custom designed mounting brackets. They have been designed by fellow users.
BLTouch 3D printer sensor is being improved all the time and no is in V3 release.
Aurarum sells and uses only genuine latest version Anctlabs BLTouch sensors.
for more information please visit https://www.antclabs.com/bltouch