Ender 3 Auto Power Off

Video Link Part1 : https://www.youtube.com/watch?v=z75vz5NlzWY
Video Link Part2 : https://www.youtube.com/watch?v=1Qf6KTZ7fsc

Material
1 limit switch : http://sirichaielectric.com/ลิมิตสวิทซ์-V-156-1A5-Omron-product
2 M3 x 15mm Bolts
2 M3 Hex Nut
2 M4 x 10mm Bolts
2 M4 T Nut

Adjustments
If you set the microswitch to click when the bed is at Y=220, then it will work out of the box with Cura. I still recommend you to modify you End G-code to wait for the hot end to cool down.
The custom post-print G-code that works with Cura, Prusa Slicer, Slic3r etc.. :

End G-Code for Cura
G91 ;Relative positioning
G1 E-5 F2500 ;Retract and raise Z
G1 Z10 F2500;Raise Z more
G90 ;Absolute positionning
M109 R40; Wait for the hotend to cool down to 40C
M106 S0 ;Turn-off fan
M104 S0 ;Turn-off hotend
M140 S0 ;Turn-off bed
G1 X0 Y{machine_depth} F1000;Present print