This is a bracket for attaching the Escher Technologies Mini Differential IR height sensing board 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 attach the sensor, with space for holes for two screws. As the sensor should measure the bed height with a resolution below 50 μm, it is important that it is rigidly attached to the printhead so it does not move.
I ended up drilling one hole in the plywood piece to the right side of hotend. To make the attachment rigid, I designed these two pieces (one goes on each side of the plywood piece) to prevent the circuit board from tilting, and giving it two attachment points. See the photos.
I used M2 screws, the left part has traps for M2 nuts. The holes are made a bit big, because otherwise the ended up filled when I printed them on my printer.
The sensor itself is the connected to the unused E-stop connector on the Printrboard, and Marlin version 1.0.0-RC8 is used with three point bed measuring. Adding a 'G29' command after 'G28' in the G-code runs the bed levelling procedure before each print.
The design was made in Fusion 360.