MK8 extruder mount with IR sensor

2 Jan 2016, added mirrored version for those with extruder motor on right.
Modified to suit this sensor and a nozzle tip to motor distance of approx 30mm. http://aus3d.com.au/printer-parts/endstops/ir-z-probe
There is a gap of 0.5mm under one side of the ir mount to allow the motor mount to be tightened.