This mount can be used to attach the BLTouch sensor to the Wombot extruder carriage.
The BLTouch sensor uses a hall effect device more details are here. https://plus.google.com/u/0/collection/8sQ5DB

The arm attached to the extruder mount body with m3 x 10mm screws/nuts. The BLTouch attached to the arm with m2.5 x 10mm screws/nuts. The slot allow for quite a bit of initial adjustment due to the variances in mk8 extruders.

See it in action on youtube https://youtu.be/B4yzOQo7iYY

Note: This is not an official Wombot upgrade it is just alternative that I did for my own testing. The owner of the Wombot printer design is http://www.aurarum.com.au/