Need to pause a carve? Grbl Feed Hold/Cycle Start

I have the E-stop, a power button, a cycle start, a feed hold and a reset button.

I agree the power button works just as well as the e-stop, but I find 3 separate buttons for cycle start, feed hold and reset to work well.

1 Like

My case is just extremely minimalist (single latching switch hopefully for feed hold and resume), SuperPID display, and a dial for the router’s speed (I use a switching pot so I don’t need a separate on/off switch for manual vs gcode speed control), so I’m trying to avoid cutting any more holes if I can. I think what I can do is have two relays (for each latching state) and then run a capacitor between the relay and ground so that when the latch hits either pole, it connects to the feedhold/resume pin while also charging the cap for a fraction of a sec. Once it’s charged, it would trigger the relay to shut the pin connection off.


You could use a momentary on/off/on switch. Hook the feed hold to one of the “on” positions, hook the cycle start to the other “on” position and hook the common to ground. About as simple as it gets.

I can’t really do that without changing the type of switch I have, and my case already has its hole cut for that particular switch (19mm angel eye). I am really dead set on keeping the current hardware setup, so if I cannot get my latching switch to work with hold/resume, I’ll just go the e-stop route. However, I’m pretty sure the relay setup I’ve got in mind will do the trick. Just means I have to bolt in an extra circuit board, but I still have a bit of room.
EDIT: I also had a thought this afternoon that I could potentially just use one of the Arduino’s free pins and recompile GRBL with a single pin that signals feed hold when it’s switched to high (and latched there) and then resume is signaled when it goes low. I haven’t even looked at the code before building it, so I’m not sure of the feasibility, but if the above circuit won’t work, that will be my next step (or vice versa if it looks really easy to do on first glance)
EDIT 2: I just found the STATE_SAFETY_DOOR flag in GRBL, which appears to be what I’m looking for…just a compile-time change to assign it to the feedhold pin, and the documentation says “Safety door is ajar. Feed holds and de-energizes system.”

1 Like

Hi Erik,

I realize this is quite an old thread, however I had actually purchased these buttons yesterday from my local electronics store. Seems to be the exact 24v momentary switches as you linked to.

I will wire each of them up in typical fashion as momentary switches to start with. I also Have my power in the control box as 24v, so this helps already.

How did you wire these up so that they illuminate and stay illuminated when pressed? How do you cancel the paused illuminated state if you press the continue/start button?

I am hoping you may have the time to show me how you achieved this. I could not find any wiring diagram online for these illuminated momentary switches.

Thank you.

Here is the post where I explained exactly how I wired them up…I hope it helps.

1 Like

Awesome post mate. I will have a good read through this tonight. If I have more questions, at least I know you are still around to ask. many thanks.

1 Like

I am not @ErikJenkins, but I think he just had these wired to be always on. They are momentary switches with an LED inside. I’m not sure they’re wired as indicator lights.