Using M581 - External Triggers and Building a Control Panel

The DuetWifi is hands down the best controller on the market. The only downside is that it doesn’t come with a display/control panel and it’s only compatible with the PanelDue displays. I’ve recently purchased a 5″ PanelDue but for a long time adjusting the Wildbot was troublesome. It involved a lot of walking from my computer to my printer and back. I used triggers and external buttons to solve this problem.

• Some kind of Pushbutton or switch (I used Idec and Allen-Bradley brand pushbuttons with Normally Open contact blocks)
• Dupont connectors
• Wire

You want to connect one side of your switch to gnd or the negative coming from your power supply. The other side of the switch will go to a pin on the expansion header. The best way I found to do this is to use Dupont connectors.

If you look closely you'll see that I used 2P Dupont connectors but only one of the pins has a wire going to it. This is because 1P connectors kept falling off so I put a wire in one side of a 2P connector with just an empty pin in the other side.

I used the following pins:

• Pin 4 = E2_STOP
• Pin 9 = E3_STOP
• Pin 14 = E4_STOP
• Pin 19 = E5_STOP
• Pin 26 = E6_STOP
• Pin 44 = RESET

Pin 44 forces a reset when shorted to ground so that button was easy enough. For the rest, I had to make changes to the config file. I found the following digging around RepRap.org:

M581: Configure external trigger
Parameters
    Tnn Logical trigger number to associate the endstop input(s) with, from zero up to a firmware-specific maximum (e.g. 9 for RepRapFirmware)
    X, Y, Z, E Selects endstop input(s) to monitor
    P Reserved, may be used in the future to allow general I/O pins to cause triggers
    S Whether trigger occurs on a rising edge of that input (S1, default), falling edge (S0), or ignores that input (S-1). By default, all triggers ignore all inputs.
    C Condition: whether to trigger at any time (C0, default) or only when printing a file from SD card (C1)

In RepRapFirmware, trigger number 0 causes an emergency stop as if
 M112 had been received. Trigger number 1 causes the print to be paused as if M25 had been received. Any trigger number # greater then 1 causes the macro file sys/trigger#.g to be executed.

So, in order to get buttons for pause, home, ATX on, and disable steppers, I had to add the following to my config file:

; Input/Output
M581 E2 S1 T1 C1         ; Pause - PIN4
M581 E5 S1 T3 C0         ; Disable Steppers - PIN19 - trigger3.g
M581 E4 S1 T4 C0         ; Home All - PIN14 - trigger4.g
M581 E3 S1 T2 C0         ; ATX On - PIN9 - trigger2.g

Finally, I had to add macro trigger files. Which are just text files containing the respective commands saved as trigger#.gcode.

;tigger2.g
M80            ; ATX ON

;trigger3.g
M400            ; Finish Current Moves
M18            ; Disable Steppers

;trigger4.g
M400            ; Finish current moves
G28            ; Home all axes