E3NG 1.2 - Integrated Filament Sensor

Integrated filament sensor for use with internal spool holders.
Replaces the integrated reverse bowden/filament guide on the rear right corner.
Can be installed as an in-place upgrade without major disassembly.

Internal geometry pinched from the Voron V0.

BOM:
1 x ECAS04 collet
1 x MR85 Bearing - doesn't need to be high quality.
1 x M2x10 or M2x12 self tapping screw
1 x Subminiature Microswitch

Instructions:

Printing:
Print in the existing orientation - you will want to add supports of your choice underneath the sensor body and the overhang for the bearing stack. The small cutout for the rod doesn't really need supports.

There is a super-thin wall right on the edge - don't worry if your slicer doesn't pick this up, it's pretty inconsequential.

Once printed, clean up the bearing stack section with a file or sandpaper so it doesn't catch on the bearing.

Sensor Assembly:
● Discard the bottom-most rubber piece of the ECAS04 collet
● Insert main collet body into the most obvious hole - this will be a fairly tight fit, you may need to press in with a vice or similar.
● Insert collet 'wedge' (loose plastic piece) into the top of the collet - this should go in a fair bit easier, but you may want to press in with the vice again.
● Insert MR85 bearing into slot - should be a loose fit.
● If your microswitch has a lever, remove it.
● Solder leads to microswitch - one to common and one to normally open (usually the middle pin).
● Orient the microswitch so that the button is over the MR85 bearing and secure with one M2 x 10mm or M2 x 12mm self tapping screw

In-Place Upgrade:
● Remove any top corner braces you may have added to the top rear right corner
● Slacken off belt tension on both belts as far as it will go and pull the gantry forward. Pull all the belt slack in so the belts are not really touching the rear-right bearing stack.
● Loosen, BUT DO NOT REMOVE the M5 screw holding the original part in place - you want to just disengage it from the threads in the heatset, no more.
● Undo and remove the 2 x M3 screws holding the original part to your machine - you will reuse these screws. Go ahead and start them in to the sensor assembly now.
● Pop the sensor assembly on your printer bed - you want this within easy reach for the next bit.
● Take something reasonably thick e.g. 3.5mm allen key and insert into the M5 heatset from below.
● Slowly pull the M5 bolt upwards, and follow it along with the allen key, so that you have something in the bearing stack at all times, because reassembling it in place will be a PAIN.
● Replace the old part with the new integrated sensor, and follow these steps in reverse to install the bolts again.
● Reinstall corner braces, get your belts tensioned, plug in your shiny new sensor and configure as normal.

Info:
I have tested this with a number of different filaments without a hiccup, but as always, presented as-is, ymmv etc.

If you need to increase the sensitivity or end up getting false runouts when filament is still in the sensor, you can wrap a couple layers of kapton tape around the MR85 bearing to make it a tiny bit thicker if needed

Borrowed Internal geometry from V0, attached to E3NG