ercf enraged rabbit optical endstop for selector

In the ERCF original design, a mechanical micro switch is used for selector endstop.

with this design/these parts, we can use a optical endstop.

This design with the following ideas in mind:

1. Print less, no huge parts, all parts can be printed in very short time and little filament/cost.
2. Easy to install, no need to disassemble the ERCF a lot of parts, just one top panel, 3 screws.

I could have designed it a bit prettier but that would have require print a few more new large parts to replace the existing ERCF parts, that would have need us to disassemble a lot of parts, a lot of work, I wonder how many people are willing to do that. so no. for example the endstop hole if can be larger, then the optical endstop can stay closer to the door/hole

so that we can have an optical reliable endstop.

For the optical endstop hardware/electronic part:

see picture. it's very cheap, about $0.80 each.

Other hardware, use 2.6mm self tap screw 8mm long  2pcs.  to hold the optical endstop on the mount.

2.6mm self tap 10mm long 1 pcs, to hold the mount under the top panel.

Install steps

1. print all parts - A new top panel with a new screw hole,  B optical endstop mount, C light blocker.
2. Eject filament from ERCF current gate first if need 
3. Release the two latches for the M8 rails, if couldn't, use flat head screwdriver to pile it from bottom.   Don't do it too hard, don't hurt your fingers or eyes!! ( If don't like it to be so tight, can use a round filer on it and add some grease. ) 
4. With 2Xlatch released, Rotate the M8 rail part upward. so we have space on the ercf top panel. 
5. remove the ERCF top panel, just release 3 screws on top, easy.
6. find a way to remove the original micro switch, 1.5mm hex wrench/hex key. may not be very easy, since there is no hole to let the screw driver in, but it's not too difficult. anyway, I spent 20minutes to release those two M2 hex holding the old micro switch, unplug old wires from ERCF.
7. use M2.6 8mm X 2 to hold the optical endstop on the small mount piece.
8. use M2.6 10mm to hold the mount under the new top panel.
9. route the optical endstop's cable, put the top panel back in place. Tip: do it at a angle, not difficult, at a 30degree -45degree…
10. Plug the 3 wires, VCC Gnd, signal to ERCF pcb. Their order is most likely not the same as your ERCF pcb's plug/socket,  so check wire/pin definition order and check again.
11. install light blocker with a M3 screw on selector ( it has a M3 already in the original ERCF).
12. check it's working correctly: in webpage mainsail → machine → query endstop, when selector is not home, it's open, when it's home (light blocker is inside the hole), it's triggered.  if it's reverted, check hardware config, may need to revert the pin with a !

I use  ERCF sensorless home.

FYI, this is my another design, button style optical endstop, a bit more difficult to install and require some extra hardware though:

https://www.printables.com/model/598672-ercf-enraged-rabbit-button-style-optical-endstop-f