Continuing the discussion from Laser Cutter Usage Timer:
Hello. Many users are asking for a usage timer. A simple device that lets them easily track time for their jobs. One like @cottjr would be great.
Is anyone willing to build one or 3 of these for the lasers?
Hi all - Iām willing to help somebody pick up and run with the teaser sample proto that I built. That first sample just needs to have a potentiometer replaced with fixed resistors, and then a more robust mounting arrangement than @larrydag and I cobbled togeher before. @EvilFrog has also issued a pull request to the Arduino code to extend the EEPROM life long beyond any expected laser life. Itās all available at GitHub - cottjr/DMS-Laser-Cutter-Usage-Timer: Code and related documentation for a Laser Cutter Usage Timer, created for the Dallas Makerspace.
Iād have done the resistors and code by now, but this new job has demanded some crazy hours, and I havenāt been able to make much progress on any project.
I also have a plan for replicating the design, which could be a cost-optimized re-layout as @william_petefish offered, or could be a simpler break out style carrier for an Arduino nano v3.
I would like to get involved with this project.
Let me know if you need the CAD designs of the box. I believe they are on one of the laser PCs shared directories. Iām pretty sure I still have it on my laptop.
Hi. @Bill , it looks like you are the team lead on this 
Yes, I will take that on.
I am busy on another project for the next month or two, then I will get on it.
In the meantime, I will try to get familiar with what had been done.
Iāll help too. Got a little more time now that others are leading electronics. 
Soooooā¦ The timer shouldnāt be further improved for the FSL. If you are going to work on it please get it working on the lasersaur and then you can modify it to work with the nova when it comes in.
From the scope screenshots, it looks like the tube trigger pulse is reversed between the two lasers. We could tweak the interface board to have a switch setting for either.
We wonāt know about the Epilog Zing until we fire it up. Very likely different since it is an RF tube.
I agree we should have a common solution.
I can get the zing going for anyone wanting to test it for this project, it just takes some setup. Just let me know if you when you want to run your tests
Cool - Iāll replace the pot with 2 resistors on the proto we made for FSL last year, and take a peek at the arduino pull request from @EvilFrog. Who might be interested in a Lasersaur electrical integration test session in the next couple of weeks?
I had a chat with John @talkers at the Space tonight and I thought I would share this line of thinking with the group.
My interest lies well beyond merely putting timers on the laser cutters.
Longer term, I would like to help build a Space-wide payment system, from laser usage to filament to plywood to art supplies. Any research and work I do on this project will be with an eye on a future means of automatic billing.
That said, Laser should think beyond simply charging for time. I have read that wear on the tube and the power supply is more pronounced at higher power levels. Charging strictly for time may be easier to implement, but it perversely promotes the practice of using high power at a higher speed instead of lower power at lower speed or with multiple passes. The effect is that we are getting paid less for more wear on the cutter. A different pricing structure, when we have the technology to automate it, can encourage prolonging laser life.
But multiple passes at lower power leads to more mechanical wear and longer wait times to use the machines. Iām not sure that we would want to introduce financial incentives to tie the machines up longer.
Sure - a measurement system can be as granular as you want it to be. Even if there were diminishing returns on gauging operating costs to the nearest penny, or cost incentives to drive undesirable use patterns, there could still be value in the learning for such a project.
On the other hand, starting with the simple timer system as we did last year is a quick & easy incremental way to at least get insight to correlations between tube āon-timeā and maintenance issues. I just need to get that back in playā¦
Where a lot of interest comes from is raster engraving. The issue is that it may take 30 minutes to scan the area, but was the laser on for 5 minutes in a sparse pattern, or 20 minutes because it is a really dense engraving? Also, while I suspect engraving is often at a lower power, it has a lot of laser tube starts. I suspect that in the correct usage model, starting the laser tube is actually one of the higher wear actions, even more than running at high power.
A Co2 laser has more than just carbon dioxide in it. It has a mixture of other gasses as well. The purity of these gases and mix ratios effect the life of the tube. Running at max power can embed impurities into the cathode and reduce power. As well as degrading the mirrors, especially the output coupler. Tube life is not only the time used (turned on) but the elapsed time since manufacture. Some of the gasses can leak through the seals while sitting in storage.
If you see a sudden drop in output power, resist the urge to crank it up to finish a job. Most tube failures are due to making an existing problem worse. Kinda like flooring the gas pedal in response to someone brake-checking you.
The epilog laser is a different design with an all metal RF excited tube. They can have lifespans of up to 10,000 hours. Synrad has tube designs that last up to 45,000 hours. Granted these tubes start at 15x the cost and are for bigger machines.
If we monitor optical power output as part of preventive maintenance on a regular schedule, we can gauge the lifespan and how usage effects the life. I believe that the laser committee now has a power gauge. Not sure if it is a time/temp style or electronic.
We can actually refill our onetime use tubes with a vacuum pump and bakeout oven. Airgas sells 3-4 different gas mixtures depending if a sealed vs flowing tube. I have a 35w RF tube that I have refilled several times. RF tubes are pretty easy to fill as they have a copper fill tube vs glass.
the tube gauge is time/temp.
Im not sure we can easily get into the tube for the epilog, its pretty built into the block that it has but id be interested to know if we could refill it
FWIW: Iāve updated the usage timer which was previously mounted to the Full Spectrum. The hardware had a potentiometer for LCD contrast that went intermittent, and is now bypassed with fixed resistors. And I incorporated the Arduino code pull request to make the flash memory last much longer (thanks @EvilFrog).
Code and schematic changes can be found in GitHub - cottjr/DMS-Laser-Cutter-Usage-Timer: Code and related documentation for a Laser Cutter Usage Timer, created for the Dallas Makerspace.
So now itās ready for a āfit checkā on the LaserSaur (assuming thatās the best laser to mount this first unit on).
Would anybody be available / interested to work with me on a fit-check integration, perhaps on Saturday 23 March, perhaps in the morning or the afternoon, or sometime else when the demand is relatively low?
I recommend the following steps.:
verify the ālaser onā signal polarity with an oscilloscope. If itās what I documented from last year, the LaserSaur had the opposite polarity from the Full Spectrum. If it is opposite, weāll make a quick polarity change to the Arduino code
temporarily connect the usage timer. Itās just three wires (ground, +5, signal).
try it out with sample cuts, eg. 100% duty cycle as well as rasterā¦
brainstorm different mounting and cable routing options
brainstorm next steps e.g.
5a. if anybody would like to volunteer to replace the blob board I made with a proper circuit card carrier for the Arduino nano
5b. and make additional copies for other equipment
5c. or otherwise extend the design
5d. and write up changes if/as needed to laser cutter training & usage policiesā¦
As Iām not trained on the LaserSaur, at least one person will need to help me
Shouldnāt take more than couple hours, with most of that being equipment roundup, digging into the guts and deciding what to do nextā¦
So whoās in?
@cottjr I am thrilled you were able to make use of modifications to the code. Hope it serves us well for a long time.
Memory serves me right, the LaserSaur doesnāt raster, so that should speed the testing up.