I converted my LR3 from an SKR pro 1.2 to a Jackpot control board.
To give myself a little more wire to play with while I was at it I extended my laser cable.
After trying to figure out why I couldn’t get it to fire on command I deduced that I managed to flip the polarity of the laser connector. This created a short when the Neje test module was powered. Polarity has been fixed, but gpio.27 now appears to be inoperative - almost certainly due to my error.
Fortunately gpio.26 works and the laser fires fine using it.
However gpio.26 is not advised for the laser due to a startup pulse.
I am rather cautious about the laser and very diligent about make sure it is un-powered unless truly intended, so the startup blip is probably non consequential, but I would like to explore other options:
get another Jackpot and re-task this one to a machine that I am not going to have a laser on.
try to fix gpio.27 - my son is pretty good with smd soldering, but I think this is probably not worth the trouble or risk of making things worse.
use one of the full-voltage mosfet pins (ie gpio.2) and a level shifter / optoisolator.
use one of the full-voltage mosfet pins as an enable signal to an ssr that provides power to the laser
open to suggestions
BTW, I love the Jackpot controller. Option 1 is probably inevitable in time so I could pull the trigger now. I am currently running an MP3DP-V2 with a smoothieboard (was originally RAMPS) and MP3DP-V3/Repeat with an SKR pro and bdring MPCNC controller on my Burly. So far, Jackpot is the best all-around board I’ve tried, but “if it ain’t broke” its hard for me to do a wiring / controller conversion just “for fun”.
Any advise is appreciated!
Snarky comments about difference between red and black wires are fine too
Some options:
You could get a replacement jackpot.
You could have your son try to replace U1 (See below from schematic) as it’s an inexpensive part and should be straightforward if he’s good at SMT soldering.
You could look into finding a module for the expansion slot, where there are more GPIOs available.
Spare ESP32 is a good idea, but probably not whats wrong here. U1 plus those series resistors are there specifically to protect the ESP32 from this exact problem.
Edit to add- there is one more thing you could do- you could find an SSR module to control power to the laser and then use an enable pin to turn the SSR on/off. That avoids the startup blip on GPIO26. But, the SSR is more expensive that the 5V expansion module so this probably isn’t a good option, unless you want the added security of a 2nd safety on the laser. (E.g. what the enable is for in the laser config in the first place). To be clear, this means using both GPIO 26 as PWM and the enable pin to run the SSR.
Most folks aren’t using an enable with the laser- but it isn’t a bad idea.
Thanks all, I hadn’t thought of getting a 5V module - that sounds like a great idea. Will probably be the most expensive option since I’ll bundle a bunch of stuff with my Tindie order, but that makes all the other things free, right?
FWIW, as people suspect, it is unlikely the ESP32 module. I got my Jackpot with the standard internal antenna and also got an external version ESP32 module at the same time. Behavior of gpio.27 is the currently the same for each and I only had the short with one of them installed.
I have an unused SSR somewhere, and that has its appeal, but is also probably the biggest wiring headache. The 5V module should drop in easily and then I can maybe add some other stuff in the future if I get ambitious.
I’ll make sure to put in a spare Jackpot board in my next V1 order too. Those things are going to be a big success story. I am running the external antenna ESP32. It has a somewhat stronger signal at my PC, but I haven’t actually notice any performance difference, so I’m not sure I would bother next time.
