Dan Maloney
Hi everyone, welcome to the Hack Chat. I'm not sure I saw Seb login yet - are you here, Seb?
Oooh, it's THAT kind of laser artistry
Yes indeed
Yeah those lasercubes are neat
I laser cut leather phone cases and stuff? ^^
they are indeed, ive had em since prototype
and its predecessor of course
Hi Seb! Welcome!
Hi everyone! Sorry I'm a bit late, I was in the wrong place 😊
lol
hi seb
No worries, welcome to the Hack CHat Seb. And thanks everyone for turning out today to learn a little about Seb's work with lasers.
Can you start us off with a little about yourself, Seb?
Yeah sure! I'm a maker, artist, coder, laserist, and I specialise in large outdoor interactive installations. I've been working with lasers since 2013, and I've written my own laser control library. My plan this year was to replace fireworks with LED light sticks and lasers, that's been somewhat scuppered by the current situation so I've now been working on a couple of 3D printed medical PPE projects. AMA, I guess? 😊
Yeah, we've been doing the medical PPE side of things lately too. What kind of output are you looking at for these lasers?
I generally use multiple 12W RGB lasers but I've used a couple of 30W previously. I have built up quite a collection!
what do u think about using someting like the tap strap 2 keyboard to control stuff live
*googles tap strap 2 keyboard*
Ooh, so you're actually in the range our beam combiners can get our solid state lasers up to. Sweet.
I was really curious if you could do any of these things with 8-14W solid state, sounds like yes
oh looks like a fun controller - would definitely be fun to play with that
what's a tap strap 2?
think nintendo glove for the nes but cooler
Oh, air keyboard
it looks a bit like the MIMU glove
yeah
What kind of safety precautions do you have to take when working with lasers in a public display?
do not point in peoples faces
ever
In my experience the laser side has been the easy side. Deflecting the laser in a controlled manner is the hard part. What do you use? Galvos, servos, steppers?
Have you ever used MEMS scanning mirrors rather than galvos out of interest?
That's always a good start :)-
Do not look into laser with remaining eye
lol
MEMS scanners dont get used for laser display (as in show) applications too often because they can't take the required power density.
literally burns the optics
@riley.august You have a remaining eye? I'm jealous :)
@Cerrid - good question, I generally don't point lasers at humans, if you want to do that there's a whole bunch of extra gear and paperwork that you have to do. The main thing is making sure that the laser beam can't go anywhere you don't want it to. First you limit it in code, then you limit it physically where possible, using metal foil tape. You also have to look out for reflective surfaces, glitter balls etc. There is also an emergency stop button that breaks a special connection in the laser and causes it to immediately cease.
Generally you don't want a laser to be anywhere below 3m above the ground where the public go.
seb what kinda DAC do u use
@matthewkleinmann the standard these days is galvos. There's an analogue standard made by ILDA, the International Laser Display Association.
So the emergency stops you guys use aren't just power interlocks?
ah interesting @david.francus
@psycon mostly I use etherdreams but my code also works with laserdock (the same controller as in the laser cube), IDN (the new standard from ILDA) and I'm working on a couple of others.
The laserdock can be good if I'm just doing a quick demonstation - it's USB. Otherwise I'll set up the whole network and put multiple etherdreams on it.
@riley.august yeah if you just pull the power it's bad - the laser won't turn off immediately and the galvos will likely swing to their greatest extent. That's why you have to use the interlock system in the laser.
I've done a ton of work in the last year or two figuring out smart ways to manage this that I will go to in excruciating detail if that is what you want 😊
I have not done laser stuff since the C64 days, I had a pretty cool setup with a HeNe tube, a pair of 8 bit ADC's that sat on the expansion port of the C64 that drove power opamps, pen galvos from an old pen plotter and a rotary solenoid to interrupt the beam. Things seem to have changed a lot. Lots more inexpensive powerful lasers and crazy cheap electronics.
What software do you use to drive everything?
@matthewkleinmann yeah it's ridiculous now. When I started I could only ever afford to rent one 12W laser for £1200 a day, they cost €50,000 to buy, now the price is about 10 times cheaper so now I own all the gear I need
nice, do u have a github or anything we can follow
What's a good starter ILDA laser?
@Jordan Horwich I've released my own laser control code library ofxLaser - it's an add-on for openframeworks and is available on my GitHub. It's quite powerful these days. @psycon http://github.com/sebleedelisle
@aerickson I really like the lasercube. It's cheap and it has a built in controller. It's not ILDA though! But my code works with it. It has bad scanners but they're great for the price. The entire thing is cheaper than just the scanners alone in one of my other lasers 😊
@aerickson if you need ILDA I have some suggestions - what power / budget are you looking at ?
laser library is at http://github.com/sebleedelisle/ofxLaser
How do you prevent or reduce the risk of people throwing reflective things in the path of the laser beam, while at festivals ?
Does ofxLaser include knobs for timing control like in the rolling-shutter demos?
I do display fireworks and one thing I thought would be very cool, but hard to do would be to put a laser on a drone and others with mirrors. Let you draw lines with many less drones. Getting it to hit a small moving target and ensuring it could never point down would be hard though.
Low power/cost for home experimenting.
@Steven Smethurst it'd have to be perfectly reflective like a mirror for it to be a problem. The laser never goes below 3m above the floor so it'd be tough.
that makes sense
What was one of your favorite events, and why ?
@Duncan Beevers it's lower level than that but you might have seen the rolling shutter effect I did with Tom Scott? (and my geekier follow up :
u did that?
that thing was cool
@Steven Smethurst I'm not sure I have a favourite. The last thing I did was my first attempt to get laser fireworks, so it was really rewarding. I built LED light sticks, and synched them up with the lasers.
@psycon yeah I'm in that video 😊
can it be done with laserdock?
Yeah, those are the videos I'm referencing. Were you tweaking ofxLaser for those demos, or did you need to hand roll-that outside of the framework?
@psycon yeah if you look at my video, the small tests I do are with the lasercube
https://hackaday.com/2020/03/05/camera-and-code-team-up-to-make-impossible-hovering-laser-effect/
Camera And Code Team Up To Make Impossible Hovering Laser Effect
Right off the bat, we'll say that this video showing a laser beam stopping in mid-air is nothing but a camera trick. But it's the trick that's the hack, and you've got to admit that it looks really cool. It starts with the [Tom Scott] video, the first one after the break.
Have you worked with lower-wavelength lasers and glow-in-the-dark surfaces for persistence effects?
@Duncan Beevers it's done via ofxLaser to manage the laser output and positioning, but I'm sending it raw data. So kind of bypassing all its graphics optimisation abilities
oh i didnt see that part of the video.. such a cool effect tho.. ive always loved how the shutter effect looks in some video captures, amazing how you eploited it
@Duncan Beevers I haven't but check Christopher Robin Shorts work if you haven't seen it
Will do!
@psycon it was a really fun project
@psycon the laser cube bit is in my video
@Seb Lee-Delisle Yes, actually, I would be really interested in hearing more about safety interlocks for lasers. We mostly make industrial lasers and for outdoor use there's much higher response time standards, from what I'm picking up. I'm really interested in the reqs for that.
@Riley professional lasers will always have an interlock input. They're often RJ45 but can also be DB9, XLR, or random connectors. They're hopelessly non standard. The laser will only work if the two wires of its interlock connector are connected.
So if you have 8 lasers, each one will need its own cable and its own stop button but that's ridiculous. Some lasers can daisy chain the interlock signal but that depends on you using all the same brand of laser.
So what I've been working on is twofold.... it's getting geeky are you regretting this yet @riley.august ?
1. How to manage multiple lasers with different brands and formats with one stop button
2. How to reduce all the cabling by using spare wires in a CAT5 cable to sneak the interlock signal down it
so in answer to 1 - I've built some custom boards that take one stop signal and break it out into multiple stop connections using relays
And the for 2 - those signals are routed down the same CAT5 cable that is driving the network signal for the lasers controller
Once that cat5 cable gets to the laser, I then need to split out the interlock and data parts
Here's the design for the splitter case
Here's the board that incorporates the relays and a network switch
*everyone tunes out* haha
If you check my instagram https://www.instagram.com/seb_ly/ you can see the fireworks project that I mentioned
lots of pictures of the build process too
@Seb Lee-Delisle umh, what was that? =8-) Seriously, do you you physical relays or a form of electronic relay?
err, do you use physical relays or...
all my documentation is videos so kinda hard to post here but check my showreel at
@cerrid the original boards I designed (and still use) have electromechanical relays but I recently switched to photorelays
Possibly more interesting things on my youtube channel which intermittently has interesting things https://www.youtube.com/channel/UCD_8q1KAC3vzQumIsN7Zsig
How did you get started with lasers?
Question more on the history of lasers: before the current generation of LED lasers, were they mostly using tube lasers? Seems really sketchy for the abuse of being on the road (thinking concert lasers here).
@aerickson it was for PixelPyros - an earlier digital fireworks installation. Pixelpyros.com
It used ordinary projectors but it wasn't bright enough, so I added a laser to it to get extra sparkles. Since then it kinda escalated.
@Seb Lee-Delisle also, @aerickson asked earlier about a low power/cost laser recommendation for home experimentation, is the lasercube the recommended for that or would you recommend something else?
@Dan Maloney yeah I think they were using gas lasers and even a 1W would be the size of a car and need a fresh water supply for cooling. I know little about those days but I'm glad I'm where we are now!
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