Ultra Compact Opto Z-Probe for Mendel with Diamond Nozzle

You need the following printed parts:

* 1x Probe V2 body * 1x Probe-Bar

Get additional parts:

• 2x screw M3 x 30mm
• 4x screw M3 x 12mm
• 1x screw M3 x 40mm
• 8x nut M3
• 2x nut M3 self-locking
• 1x screw M5 x 50mm
• 1x nut M5
• 1x nut M5 self-locking
• 1x Opto-Probe on PCB (e.g. Chinese product)
• 1x Servo SP90 (e.g. Chinese product)
• 30 cm of thin isolated flexible cables
• 6cm shrinking tubing, fitting the cables
• 1x cable-tie 6mm x 180mm

A first sketch of the idea.

Preparing the probe

• Pick up the M5 x 50mm screw.
• Use a saw to cut off the screw's head
• Use a file to shape about 20mm of the one side of the screw. Dimensions about 4,2mm x 2,8mm.
• Use a saw to cut away about 8mm of the thread and form a point at this end. Overall length about 4,2 cm.

Finally your probe should look like this

Probe bar assembly

Put the M5 nut into the printed probe bar and screw in the probe. Use the self-locking m5-nut to fix the probe in place.

This is the probe bar assembly

Opto-Barrier modification

Because of the compact design the Opto-barrier and PCB have to be separated.

• Us a solder iron to unsolder the barrier and remember which pin goes to which pad.
• Connect a wire to each pin and protect it with a small piece of shrinking tubing.
• Solder the open wire-ends to the corresponding pads of the PCB.
• Mount the Opto-barrier and the PCB onto the printed probe body using M3 screws and nuts
• Place the wires in the trenches of the printed body part.

Attach probe bar to probe body

Put two M3 nuts into the foreseen pits of the probe body.

Attach the two M3 x 30mm screws. They will act as guidance for the probe bar.

Probe retracted.

Probe extended. The M3 nuts acting as stop are missing here.

Final tips

You'll need the M3 x 40mm screw to attach the probe assembly at the x-carriage. Do that before mounting the servo with the cable-tie because the screw is situated underneath the servo!

Before you connect the Servo to your controller make sure that it provides enough power for the servo - or you can damage your controller! Better: Use an external powersource.