Creality filament runout sensor mount

Creality Ender 3 filament runout sensor mount using a simple micro switch. The lid press fits onto the base plate, no screws required. It mounts under the extruder using the stock hardware.

### Parts
1x [Engelec KW micro switch](http://www.engelecgroup.com/Micro-Switch-KW-Series-pd44544765.html)
2x PTFE Bowden tube pieces
2x wires
1x JST PHR-3 connector

### Wiring
| Micro switch | |Filament sensor port|
|---------------|-----|----------------------|
|COM| |Signal|
| NC | | GND |
| NO° | | VCC° |
*° not connected*

### Marlin firmware settings
These are the settings for Marlin v2.1.2.1 on my Creality Ender 3 :

_Configuration.h_
\#define FILAMENT_RUNOUT_SENSOR
\#define NOZZLE_PARK_FEATURE
\#define EXTRUDE_MAXLENGTH 500

_Configuration\_adv.h_
\#define ADVANCED_PAUSE_FEATURE
\#define FILAMENT_CHANGE_UNLOAD_FEEDRATE 100
\#define FILAMENT_CHANGE_UNLOAD_LENGTH 500
\#define FILAMENT_CHANGE_SLOW_LOAD_FEEDRATE 10
\#define FILAMENT_CHANGE_SLOW