Inline filament diameter sensor using hall effect sensor -remix of infidel model from @MadeWithLayers

The block feels more robust with PC4-M10 fittings absorbing the friction on the input and output. Access to the grub screw for the spring is still open.  Cut away the port printing support after printing

Use a 5mm grub screw for the spring

Also I have spare 8x3mm magnets in stock which will simplify the BOM a little.

Be prepared to code your own firmware as a larger magnet will likely increase the detected magnetic field strength.

If coding is not your thing then it's best to stick with the original model. To use the original firmware simple print the original lever and source a 2x6mm magnet. The modified block with ports can still be used.

If using Cura slicer goto experimental settings → slicing tolerance and set it to exclusive. Otherwise the project may not fit together

 

Slicer settings : 

PETG

Use a raft to help combat warping. The raft takes an extra 8 minutes and 2 more grams of plastic but the prints are satisfactory in my experience

Bed temps 80C, nozzle 235C

Initial layer height 0.2mm, consider adding -0.1 z offset 1 manually on the printer controller (relative to your optimal PLA z offset) as this makes the PETG stick better. 

16mm layer height, 25% infill, 0.4mm line width

3 walls, 3 top & 3 bottom layers

Print jerk 10 mm/s

Retraction enabled, z hop only over printed parts, z hop height 0.24

initial layer speed 10mm/s

print speed 60mm/s , outer surfaces print speed 45 mm/s