Laser Test Firing

OpenGlow Control Board
1

After being taunted by @palmercr about being a whining wanker, I sucked it up and got back to work on the toasted power supply. (Seriously, though, thanks for all your help, @palmercr!)

Good news - it’s back and alive.
Bad news - there still is some work to do to.

Some video:

You’ll note that when it reaches the bottom of the left line for the P, it quits. This is caused by the board rebooting.

Why is the board rebooting? I’m assuming a power supply issue at this point.

This is the result of what it did burn:

IMG_20180816_192426
IMG_20180816_1924263024×4032 3.24 MB

10 Likes
2

:smiley::smiley::smiley:

3

Thank you @palmercr for the tough love

4

I think all I actually said was "Sorry to hear you are giving up. "

5

Even the stock GF’s seem to have resetting problems, especially early on. Maybe when you get to the bottom of it we will find out why.

6

Congratulations on the success. When I read that you had thrown your hands up and quit over a power supply, I thought that maybe the August heat got to you. I could not believe that your embedded hardware and software Fu could be beat by a lowly power supply!

1 Like
7

Isn’t that British slang for “you whiny wanker”?

Both the OpenGlow and the Glowforge have supervisory circuits that monitor various processor voltages. When they dip below an allowable threshold, they trigger a processor reset.

If the 3.3V that feeds the micro goes below about 3.1V, even briefly, that’s enough for the OpenGlow’s SOM to reset.

I’m going to get all the supplies wired up to my scope and let 'er rip again so I can see if any of them are flaky.

Admittedly, I was a bit brain fried.

8

I’d buy you a beer if I could. Thanks for your efforts.

1 Like
9

I’ve been out of town the last several days, and had to pause progress.

Back to testing (at least for a couple days, then I am headed out of town for another 10 days)…

I definitely have a power supply issue, though it will probably take some extensive testing to get to the bottom of it.

It will run at full power and reduced power for varying amounts of time before the lights blink and the unit resets. This only seems to happen when the laser is switched on at a set power level for intermittent periods. The test file I run is doing about a 70% duty cycle, and it will run anywhere from 5 to 15 seconds before it bites it.

Strangely, it seems to engrave alright:

And the finished product:

IMG_20180823_182913
IMG_20180823_1829132823×2121 1.74 MB

At this point, I’d like to get another prototype out there in the wild so I can validate that the resets are in fact a problem with my power supply and not how the supply is being driven by the board.

Any takers?

10

Is that hardware 70% PWM or the software “precision power” dithering?

11

I probably should have used a better term to describe what I meant. I was referring to how much of the time the laser is on while running the cut program.

The PWM is set to an 80% duty cycle, which is full power on my basic.