It's been a long time, but I'm finally back..
Moving this week (Chicago area) but never stopped tinkering with things Arduino. Latest creation is a laser engraver made with salvaged rails, two EasySteppers, a Nano running GRBL, and a cheap Chinese 2.5w blue-ray laser off the net.. works fantastically!
Good to see so many folks still around..
Later!
Hi focalist,
What is 2.5V strong enough to engrave? I have no sense of what power is needed for what material.
Little typo there. What can 2.5W engrave or cut or burn thru or whatever?
Wood (my purpose) can be engraved and thin wood cut, leather, plastics, likewise can be engraved and cut. Surface engraving on glass also works to some extent. Metals are not markable or cuttable generally in this kind of low-watt device. I've seen laser modules in the 10w range, but IMO anything above a couple watts and you are better off with a CO2 laser rather than diode.
However, since the 2.5w was under $70 and even came with safety glasses, hard to beat.
My purpose is to laser engrave photos onto wood, using LaserGRBL with TTL allows for pwm-modulated grayscale burning of raster images... it's a bit tricky getting contrasts right, but it's coming along nicely.
By the way, the trick for glass engraving is to use black marker or other black ink on the glass. It gives a different effect if you engrave THROUGH the glass rather than ON the glass. On the glass gives you sharper lines but through the glass produces a pleasant rainbow effect.
I'm using glass from dollar-store picture frames, I figure maybe sidelighting might look good. It's cheap, thin glass and I do have to say I would not use this method for commercial engraving.. but it IS fun...
Here's a laser rendered greyscale image I did on a particleboard clipboard.
Harder woods like maple and oak (and particleboard) handle greyscale a lot better than pine or "craft" wood.
What's really nice is that my rails (x and y) are commercial THK sliding blocks with PowerMax II steppers.. I got them at a salvage yard for a song. Extremely accurate and powerful, tons of torque even when run at 12v. one is 300mm the other 500mm, that's a pretty large work area. Eventually, I'll add a third axis and a mount for extruder, but extremely tight on cash right now and plenty of fun to be had with what's in-hand (in addition to moving this week).. but in any case, considering the x and y, I want to make the z axis pretty solid.. as this level of hardware can take the kind of abuse CNC throws. At a minimum, a good solid Dremel mount would be in order.
Need to adjust timing and config in GRBL settings at the moment, to see if I can get better movement rates than 500mm. Even a 2.5w is capable of enrgraving wood FAR faster so it's a matter of the rails moving faster without the dreaded "hum and not actually move"...
focalist:
By the way, the trick for glass engraving is to use black marker or other black ink on the glass. It gives a different effect if you engrave THROUGH the glass rather than ON the glass. On the glass gives you sharper lines but through the glass produces a pleasant rainbow effect.I'm using glass from dollar-store picture frames, I figure maybe sidelighting might look good. It's cheap, thin glass and I do have to say I would not use this method for commercial engraving.. but it IS fun...
Long time indeed!
If you light the edge of the glass, will the etched parts light up like plastic shard lights do?
It does, but not as well as Plexi, probably due to the shallow 'cut' depth.
Went dark for quite some time.. personal stuff. When Honeywell shot down the safety valve thing, I took it badly.. lost both parents as a kid to gas explosion, let's just say I was heavily 'invested' (not money..soul) in making it happen. Techwise it is simple, a NC valve, pressure sensors before and after, and a gas sniffer interior to home. Microcontroller senses gas or pressure profile changes and NC valve releases, shutting off gas at meter. Could also of course communicate failure upstream, etc. Simple, saves lives, and never going to happen because retrofit costs would be on utilities, among other reasons. It's not the tech.
Anyway, now back out in Midwest where I grew up, tinkering, doing my thing.. a wiser if not slightly more cynical guy...
Here, in the UK, there is currently a massive scheme to replace all old mechanical (both gas and electric) meters with smart meters. Installing your safety valve at the same time wouldn't be any more work and the electronics could be incorporated into the smart meter electronics. It may be worth your while to investigate that.
However, I don't understand how your valve could work. The pressure drop when my central heating boiler fires up is vastly more than a small, yet still dangerous, leak would cause.
Also, when the valve trips, who gets to reset it, the customer or the utility?
If reset by the customer, in some cases it would render it useless. (idiot customers*)
If reset by the utility, there would have to be a dedicated team for that to avoid a prolonged break in service and, therefore, extra expense for the utility.
*I've seen a whole fusebox where blown fuses have been replaced with kitchen foil, in a commercial kitchen, so don't tell me that there are no idiot customers.
If you illuminate the glass etchings from behind it looks bright?
Tell me if this was a good eBay deal, 60 IRLZ44N for 14.5 cents each?
There were things to work out to be sure, but the bottom line is that Honeywell wasn't going to do it..and without Honeywell, forget it.. in any case, the MQ series sensors (or others) are the real key.. detecting gas where it should not be.. (eg basement)
Btw, I offered the design free.. as well as further work. It was never about money.
Was bitter and quite depressed for some time.
For my own well being, I left the project behind..
Welcome back. I recall your determination with your the safety valve project. I also seem to recall that you spend nights surfing eBay for bargains, a self confessed 'bottom feeder'? Or was that someone else?
If you have a nice word with one of the mods they might be able to convince one of the web gurus to reactivate your old account - they have done another one recently.
GoForSmoke:
If you illuminate the glass etchings from behind it looks bright?Tell me if this was a good eBay deal, 60 IRLZ44N for 14.5 cents each?
Are they real, or a misprint and you have really bought a 60IRLZ44N, which is the left side "wigwam for a goose's bridle"
Geese bridles are pretty cheap I hear. 
Bottom feeder extaordinaire! Never stopped that either.. accumulating parts that fall through the cracks on eBay..
Esp8266, nanos, power transistors, switches.. if I can get it super cheap I grab and shelve it. That being said it made loading moving truck... Tedious.. as I decided to sort to some extent while packing
Lol
TomGeorge:
Are they real, or a misprint and you have really bought a 60IRLZ44N, which is the left side "wigwam for a goose's bridle"
Geese bridles are pretty cheap I hear.
60 TTL level power MOSFETs, type IRLZ44N, best used for low side power switching. Max current 49A at 60V. 14.5 cents each.
Most MOSFETs I've found that can switch > 1A cost a good bit more. Earlier I paid 80 cents each for 12 other FETs, go figure.
focalist:
Bottom feeder extaordinaire! Never stopped that either.. accumulating parts that fall through the cracks on eBay..Esp8266, nanos, power transistors, switches.. if I can get it super cheap I grab and shelve it. That being said it made loading moving truck... Tedious.. as I decided to sort to some extent while packing
Lol
There's a place in Ohio (at least a distro point) resistorpark.com with eBay-like prices and details/support to match. That's a 2 day ship for you or me.
ESP modules under $4, bootloaded 328P $2.23, 16MHz crystal but w/o the caps -- is $1 high?
AVR prices dropped, dunno if you've seen. Microchip bought Atmel. Mouser sold 1284P around $5.50 in July, that was $7 for years before. I dunno what you think of the 1284P though but I bought 2.
Nice on the logic MOSFETs!
The actual "move" is now complete, but I am now going to undertake a terrible task before I get down to actual tinkering..
Sorting out the bins.
Bottom feeding, I sometimes get a couple of packs of components a day.. and since I get most of them with no immediate need, I simply would put them in a bin. I've done this for years. Remember, I often get a pack with two microswitches, that I paid 10 cents including shipping for. Or ten diodes. Or a couple of power transistors. You know, whatever I could pick up for pocket change, knowing I'd eventually find a use (or someone with a use) for it. There's lasers, LED's and switches. Packs of screws. Arduino Mini clones. Heat shrink tubing. Solderless breadboards, jumpers, shift registers and ULN2003's, capacitor assortments (disc and electrolytic), resistors, and frankly... tons of just plain random stuff. The key being getting whatever it was, very cheap.
So when I need a part, I often have to dive into these bins, and actually finding anything is nearly impossible. It's time. I need to take over the floor in the basement for a day and dump ALL of it out, sort and properly bin it. Daunting task... 
SO.. I've got a couple of bins.. Four, actually.. of completely unsorted parts. Kinda like Christmas, kinda like looking at a huge driveway of snow you KNOW you need to shovel...
Shit... you could stock a hobby shop couldn't you?
You got room to start a hobby club or join one? Helpers! Divvy out some parts for the work, provide caffeine, get to know each other and it'll be done in no time. You even don't mind giving some away so where's the lose but some time spent with others who share the hobby?
Teach soldering. Each time you +1 the number of parts buyers, right? Teach epoxy but check out super glue and baking soda (gets HOT briefly, gets hard, can be molded)
How long ago did you go off radar? I thought we lost you for a while there.
Henry_Best:
Installing your safety valve at the same time wouldn't be any more work and the electronics could be incorporated into the smart meter electronics. It may be worth your while to investigate that.
Modern boilers in the UK use zero pressure gas.(guage)
They depend on the fan in the boiler to draw the gas in using negative pressure.
Well, just moved to a new area (West of Chicago about 30 miles) so getting that started up here will be in the works.
I was the "go-to-guy" for parts for a lot of friends and friends of friends.. when you get the stuff for pennies, it's not too painful to give a few parts away... gave a buddy an ESP8266/NodeMCU the other day, one of the $3 ones. The geek glint in his eye was more than worth the cost
