Mini Differential IR height sensing board attachment to Printrbot Plywood Wade's extruder

This is a bracket for attaching the Escher Technologies [Mini Differential IR height sensing board](http://www.escher3d.com/pages/order/products/product1.php) to Printrbot's laser cut plywood Wade's extruder, as used on the PrintrBot Plus v1 (version 1303) 3D printer.

With this sensor, three pieces of electrical tape on my glass mirror printbed, and some adjustments to the Marlin firmware, I now have automatic bed levelling on my 2012 PrintrBot Plus!

I could not find a perfect place to att