Emergency stop switch
The purpose of this switch is to bring everything to an immediate stop in the event your toolhead is about to damage something or go beyond its cutting borders (or any other emergency). It doesn’t matter what sort of switch it is, but it must have a way to positively break the circuit. I personally like big red push buttons such as the one you see here on my machine:
Figure 6.10 – My E-Stop switch, mounted right on my 3018’s frame
You can find these on Amazon or similar sources for very little. They will have three terminals but are wired with two wires. My controller board has a two-pin terminal for this switch, but if yours does not, wire it to your connector to the board (the live, i.e., positive wire). Do not wire it directly to the plug to the wall as that would be dangerous. Install the switch somewhere easily accessible from any angle on the board. The reason I like the big red button is that you cannot...