Laser Enable on Jackpot to Control Power Supply?

I’m running a Jackpot on my primo with a laser. Just picked up a new laser tree 20w laser

I want to plug the power supply into one of these and have the jackpot turn it on when needed. Looking at the docs I see there is a laser enable section. Can I put GPIO16 there and light burn turn the laser on when it is needed? Or is there more involved in this that I don’t know about?? Already using GPIO2 for a solenoid valve for the air assist. I saw the light coming on for it any time the laser was running so took advantage. Thanks!!!

You should just be able to define the enable, but i would NOT use one of the low side switched VMOT FETS, just use whichever 5V output you’re not using for PWM (gpio 26 or gpio 27)

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Ok. Can you tell me why???

First of all, VMOT is 24V. Is your widget 24V IO compatible? If not, you let the smoke out.

Secondly, the low side switched IO is as it is named- the return is switched, not the source voltage.
That means when the output is “Off”, you’re still sourcing the VMOT voltage on the + pin, which is going into your device. Now, even if your device is 24V IO compatible, you have an input with no reference when the FET is off. At best, this is undefined and may lead to erratic or intermittent operation. At worst, you let the smoke out.
Edit: undesirable but less bad possibility, your devices share a 3rd wire ground and the unreferenced low side switch signal essentially leaves the AC switch always on, defeating the purpose of what you sent out to do.

Ok. Thanks for the explanation. The power supply said it was good for 3.3-60vdc or 12-120vac so I just assumed I was good on either. But if you suggest moving it over to the PWM side I will do that. Now just have to figure out how to tell lightburn to turn it on LOL


FluidNC should turn on the enable when the laser is in use. You shouldn’t have to do anything else. (I didn’t need to when I put a jackpot on my JL1. FluidNC turned on the enable repeatably.)

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That’s a pretty wide input range, so you most likely won’t let the smoke out if you hook it up to one of the low side switched FETs. But the caution about undefined state when not on still applies. There’s no current limiting on the jackpot for those VMOTs on the jackpot, so keep that in mide if you do choose to use the low side switched outputs.

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Awesome! Thank you!!

You’re welcome. I’m looking forward to seeing that laser setup on your machine.

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Well it works… Sort of. Now I have a new problem to figure out. I guess it takes a few seconds from the time power is applied to the laser power supply before the laser its self can turn on. So it will miss a tiny bit of each cut/engrave if it stays like this. And that wont work. So I guess I’m going to have to skip this add on unless someone knows how to make it start up faster or make the power supply come on and stay on before it tries to actually turn the beam on.

I swear Ryan did a full write up with using a laser on jackpot. I could not find it though. @Ryan is there such a thing?

On fluid you can call the gpio#:low :high and 2 variants of each, i would recommend you to read the wiki. Now that said the 5v on the board should have 2 outputs the first is known to keep some pulses at power up, (havent tested yet on my jackpot) but this is also true on my 6pack

Would be best not to use the one that glitches for the PWM signal. I have not seen glitching on my JL1, so I must have picked the good one. I vaguely remember some discussion about this before, so this should go into the documentation. The good news about using an enable, is even if the PWM signal glitches, the laser won’t turn on because the enable is not on. If both pins glitch then well it’s not a good scene and you’ll get a. pulse.

I’ll take a note to do more testing with my JL1 and see if I note any hint of this.

I’ll schedule some time to look at this on mine.

I’ll go look. Do you happen to have a link to where this is discussed?

You should take a good read of the fluidnc discord and wiki, some times its useful to read issues others have encountered or solutions you may be looking for your case that may (or not ) be resolved, that could leave some spare time to mitch or Bart, the documentation from V1 speaks about the gpio pulse at boot for the jackpot -you are using an enable pin, so you won’t suffer this- im not (on another board the 6pack) and gpio.27:high pulses constantly and gpio. 27:low is always on, ended up using another port (#4) of my 5v module. Maybe next week will be playing with the jackpot controller (one mod, i desperately need an external antenna esp32 module)

Ideed it does, at the location below:

Quick note, gpio.26 can have a quick pulse when starting. If you are using a 5V pin for your laser pin 27 is the better option for your enable pin.

but I’m not sure the language is correct. Note that it says enable pin. I think that should say output pin.
Lots of people are running only with a PWM output, not the enable (power wired directly to the laser module). I had laser module power wired directly to the JL1 laser for a while after finding out the VMOTs are low side switched.
I’ve never seen my laser glitch on jackpot power up , but then again from my JL1 thread the config ended up using GPIO27 for the PWM (Output pin).

I don’t think my problem is with the jackpot at all. My problem is from the time 110v power is applied to the laser power supply to the time the laser is actually ready to fire is too long. I think im going to have to go back to just plugging and unplugging it

I use mine without the enable pin. Just declared a tool # and let vectric aspire to handle spindle tool change via gcode. With my particular board (6-pack cnc controller) i get the diode laser pulsing at really low power, but it is pulsing ; have not tested the jackpot board yet

You could add some pause .5-1 sec before you start the gcode with the laser.

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This was going to be my suggestion. I don’t have a laser or anything but depending on your cam software you should be able to add a simple wait gcode. I’m all for trying to solve this issue completely. It’s odd to me that the laser doesn’t stay powered/idle and wait for a switch to trigger a gate to turn on. Surely that would be faster

I think your external control box is internally a mechanical relay. That’s why it takes such a wide input range for the control voltage. Mechanical relays are really slow to switch compared to solid state devices.

After thinking about that, to use that box you may actually want to use gcode to turn it on at the start of a job or work session and then wait a bit. The bummer is this isn’t really much better than just having an external power strip or something to turn the laser power supply on and off.

Can you find links to the laser tree documentation for the laser module? I"d like to read up a bit on what it expects for its inputs.