Compact Opto Servo Probe(SG90 servo) - auto bed leveling

19.07.2019 See also V2 - https://www.thingiverse.com/thing:3756428

25.05.2018 Added a new version with a longer flag (+1mm) and servo arm with increased radius(+0.24mm)

07.02.2019 - Printed in PLA does not resist in an enclosure printing at higher temperature (ABS). The flag is affected especially if it is mounted the spring.

27.12.2018 - Added back cover

Compact opto servo probe. https://youtu.be/cW87qqow3zs
Another one but has:

• BL-touch mount and the same rod axis as consequence the same x,y offsets;
• the same height as Bl-Touch;
• trigger distance 1.5mm (BL-Touch 2mm);
• stow-deploy distance 5mm as BL-Touch;
• servo angles- stow 90, deploy 10 - as BL-Touch;
• same wiring as BL-Touch;
• way better accuracy than both BL-Touch clones I own (standard deviation around 0.0015 instead of 0.006 up to 0.01)

Boom:

• Sg90 9g - servomotor
• optical endstop

2 - M3x10 screw + M3 nuts
2 - M1.5 x5 selftapping screw (salvaged from old deskjet printer)
1 - spring diameter max 3mm , 10mm lenght (salvaged from old deskjet printer) I did not see any accuracy improvement using spring.
1 - rod max 3mm, min. 21mm lenght (I used a 2.4mm diameter axis salvaged from old deskjet printer)

Assembling:
Introduce the flag in the frame (see picture) and then the rod. The ensemble flag-rod have to slide easy under gravity action. Pay attention to alignment.
Mount servo motor and optical endstop. Wire the board according BL-Touch install instruction and opto servo probe according pictures.
Install the firmware, send the command M420 S10 (deploy probe) and install servo arm as in picture for deployed position.

Stl files can be mirrored to change the position of the probe. In this case set servo angles: 90 for deploy and 10 for stow.

The figure in the name of files indicate the diameter of rod