CTC/ebay, E3D, Bowden, strain gauge Z probe

thingiverse

A Bowden E3D v6 hot-end mount for the CTC/ebay plywood Prusa I3 clone printer which uses a strain gauge for Z axis probing The hot-end mount shows no originality, the big plus is that it fits my printer and the OpenSCAD source means I can change it. A slightly modified version of the mount has a BF350 strain gauge super glued to it which in combination with an Arduino Pro Mini and a HX711 ADC provides Z axis probing. When the nozzle touches the print bed, the mount bends slightly and the electronics detect this and simulate a limit switch. The typical operating force is around 30 gm weight. The fan shroud (printed in yellow) comes from https://www.thingiverse.com/thing:2059016 A similar idea using a load cell https://www.thingiverse.com/thing:1248287 More discussion http://www.davidpilling.com/wiki/index.php/Zprobe Photos show mount with capacitive sensor and then the lengthened mount with strain gauge electronics. StrainStop04.zip (9th July 2017) is the source code of the Arduino software. The code relies on being able to see the Z axis stepper motor step and direction signals; it follows these have to be intercepted and passed on to the Arduino. The "hotend" scad files contain two pieces, the idea is that they will be edited and run once to produce the front and then again to produce the back. STL versions are included, the front is the same for both versions of the hotend mount. The "extruder" file is a bracket to hold the Mark 8 extruder to the printer. I had followed the design http://www.thingiverse.com/thing:1792366 "Prusa i3 Pro B Z axis top brackets with blocks for strengthening rods", and as a result had some M8 rod attached to the printer that I could slot the bracket on to. https://www.youtube.com/watch?v=K3higvTPbbA