Auto bed level (with Z probe) for Prusa i3 Hephestos

Due to lack of designs about probe support for Prusa i3 Hephestos I made this one.

Probe diameter: 3mm
Servo: TowerPro SG90

First test: https://youtu.be/1Zho6gh9Toc

Unfortunately photo interrupter stop working. Probably due to wrong resistor for 5V. Current was a bit too high. However this photo interrupter was at least 8 years old (from a worn desktop printer).

Credits:
http://www.thingiverse.com/thing:1164679 [TowerPro SG90]
http://www.thingiverse.com/thing:371842 [Prusa i3 He