Ender 3 Auto Shutdown

I used a limit switch and a single channel module so that my ender 3 will automatically shut down after the print is done. I always had to keep track of the time when I put any design for print and since I didn't want the printer to stay on unnecessary for longer period of time, I was never able to put the prints overnight. This is my version of auto shutdown ender 3.

Limit switch. I used the one with long clip: https://grabcad.com/library/limit-switch-cntd-cmv101d-1

5V Single channel relay module: https://www.amazon.in/CentIoT%C2%AE-Channel-Household-Appliance-Control/dp/B07PXZS7DF

3D printed parts: https://www.thingiverse.com/thing:5447295

5V adapter: https://www.electronicscomp.com/5v-1amp-dc-adaptor?gclid=EAIaIQobChMIzomkrr6p-QIVAZNmAh3GsAw6EAQYASABEgIfNfD_BwE

Female power jack: https://www.electronicscomp.com/dc-power-jack-female-with-screw-terminal?gclid=EAIaIQobChMI1p267b6p-QIVC38rCh28tgj2EAYYByABEgKyNPD_BwE

Few bolts

3D print all the parts which include a stand for limit switch and two parts of relay module case. STL files are provided above and you can also download from here: https://www.thingiverse.com/thing:5447295.

Do the connection as per the schematic attached above. For the power supply, i am using 5V adapter. With the female power jack, you can turn on/off the relay whenever you want.

Once the wiring is done, assemble the parts onto the printer. You need to do some adjustments for the proper placement of the limit switch. To fix the limit switch stand you can use the hole in the aluminum extrusion and fix it with the help of bolt. Similarly to fix the limit switch on the stand you need to fix it with nut and bolt.

This is the G-code I am using,

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

M104 S0 ;Turn-off hotend

M140 S0 ;Turn-off bed

M109 R40; Wait for the hotend to cool down to 40C

G1 X0 Y{machine_depth} ;Present print

M106 S0 ;Turn-off fan

M84 X Y E ;Disable all steppers but Z

What this G-code does is that after the print is over, the nozzle will move 10mm upwards and will wait till the nozzle temperature reaches 40°. After the nozzle temperature reaches 40° the bed will move forward and it will hit limit switch and the printer will shut down. In case you stop the print in between, the bed will slide backwards towards the Y-axis limit switch.