Ender 3 V2 Power Off Auto switch shutdown

this is for DIY and do it on your risk !

this part designed for Ender 3 V2 and I believe it will work on Ender 3, Ender 3 pro, CR6se and may others.

( ThingsDesigner ) design very useful but required to un-screw bolt and does not offer a quick remove in case of disable auto switch ( he explained how to keep the printer ON even if the auto switch is OFF but it required more experience to wire it up to the power socket of the printer or to the motherboard )

so here we are this design allow you to easy remove the auto switch when you won't use it and not required to un-screw any bolt in installation and not required any wires inside the power supply of the printer or the motherboard

see pictures above for more details how to wire the switch

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tools :
1- on off switch can handle 220V or 110V 19x13mm ( i used 220V 3 amp switch )
2- 220v or 110v and 60_90 cm long power cable, can handle at least 300 or 500 watt to be in safe side
3- printed case
4- modified your End G code in cura
( note : you can add a new printer profile named auto off , and you will have a normal printer profile and the modified one when you want to enable this function or not using it )

5- adjust your printed case so when you move the print head to X max
( x axis 245 in ender 3 ) it is not touching the switch NEVER ( it will have a 1 or 0.5 mm gap ) BE careful

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I use END G code as ( ThingsDesigner ) mentioned but he make the printer to wait 2 minute
in my opinion make the printer to wait until hot end is 45 degree is better as it list below :

In the device settings for Cura, insert the following in the section "End G code" above the last command "M84 X Y E":

; Auto-OFF
M109 R45; wait to cool to 45 degree
G28 X; Home X for safety
M211 S0; SW end stop off
G1 X248; go to power-off position
; If not powered off:
M211 S1; SW end stop on

The entire end of G-code then looks like this:

G91 ;Relative positioning
G1 E-2 F2700 ;Retract a bit
G1 E-2 Z0.2 F2400 ;Retract and raise Z
G1 X5 Y5 F3000 ;Wipe out
G1 Z10 ;Raise Z more
G90 ;Absolute positioning

G1 X0 Y {machine_depth}; Present print
M106 S0 ;Turn-off fan
M104 S0 ;Turn-off hotend
M140 S0 ;Turn-off bed
; Auto-OFF
M109 R45; wait to cool to 45 degree
G28 X; Home X for safety
M211 S0; SW end stop off
G1 X248; go to power-off position
; If not powered off:
M211 S1; SW end stop on
M84 X Y E ;Disable all steppers but Z

as i mentioned moving X axis to max (245 for ender 3 ) should not touching the switch if it does, push the printed case with little force to the right more, until there is 0.5 mm or more between them (see pictures for more details )

finally ( ThingsDesigner ) mentioned

If necessary, the command G1 X248 must be adjusted somewhat if the printer does not hit the switch correctly (manufacturing tolerance) or if the whole thing is used with a different printer. Since the software end stops are deactivated, you should be particularly careful here, otherwise it will literally crash.