!! Be very careful when making modifications at the power line!
!! Always remove the power cord!
!! I will not be responsible for any damage on your printer or on your or others body
!! that might be caused because of this description!
!! ONLY do this when you know what you are doing!
This is a customizable case/box for my SSD relais I added to increase the security of my 3D printer.
The SSD relais is a switch for my 12V and 24V power supply for the motor and the heating elements.
The SSD relais will be controlled by a signal from my Arduino DUE. This could be configured to and empty signal at the AUX connector. My SSD relais already work from 3V therefore there is NO need for an additional power converter to 5V or 12V because the Arduino DUE generates 3.3V
I also spend two thermal fuses, on of 285 degree C at the hot end - make sure you place it far away from the heating element but connected to the hot end - the best is at the opposite side from heating element I guess. And a second thermal fuse with 100 degree C under at the printing area at the heating element.
The SSD relais control signal goes first in serial to both thermal fuses and then to the SSD relais. If any fuse will fail, the SSD relais lost its control signal. There is also a ground signal going directly to the SSD relais.
The SSD relais might generate some heat, therefore it is directly mounted to the 2020 aluminium profile. There is a spare area in the case. Because of this the aluminium profile should have a connection the ground.
I drive the printer by a Raspberry PI and the octoprint software. With enables me to automatically shut down the printer after the print and when the hot end has been cooled down - there is an additional plugin for this.
It is also possible to switch the power supply for the heating elements on and off from octoprint as the Arduino gets its power from the USB cable connecting both computer. It might be necessary to enable the Power feature in your software.
I made this in the Marlin software and by defining the following in the configuration.h file.
#define POWER_SUPPLY 2
#define PS_ON_PIN 23 // D23 AUX-4 Pin 16
In this example at the PIN D23 is the Power control signal. This is AUX-4 Pin 16 on the RAMPS-FD board.
This combination works perfect from my view and increases the security. In case an heating element will overheat the device - because of whatever reason - the SSD relais will loose the controlling signal and the 12V and 24V power supply for the motor and the heating element will loose its power.
I have printed the case with transparent PLA to be able to see the SSD relais ON state indicated by a small LED on top of the relais.