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A Practical Guide to Lasers for Experimenters and Hobbyists (repairfaq.org)
162 points by Phithagoras on May 19, 2016 | hide | past | favorite | 18 comments



Laser Sam! He's amazing and has been part of Internet history since the beginning. Everything I love about the web in simple, no-frills HTML.


Absolutely! It's so good to see real HTML used to organize substantial information, instead of the high-glitz low-content stuff we see so often these days...


something that I can't find much info on is the safety of laser line generators, eg: https://hackaday.com/2016/04/04/smartphone-and-ir-line-laser...

intuitively the beam spread should make it much safer, but I'm still a bit uncomfortable with the idea of a 100mW IR laser, which is what those guys used.


Its all about how much energy hits the eye, and for infrared lasers you can't assume someone will blink, so you cant use short exposure times.

From the paper, they are pulsing the laser, so the laser is hazardous out to ~1.5m. Pg 5 of their paper goes into detail on the calculations one needs for laser safety.


It seems like they used 100mW IR explicitly so they could use the platform outdoors. In most cases, you're fine looking at the reflected (usually diffuse) light, but you shouldn't stare into the beam. If you're working indoors you should be fine with visible low-power lasers, e.g. 1mW red or green.

There are numbers in the paper (linked in the article) and they explicitly calculate the power vs the safe threshold. They basically say you shouldn't go closer than 1.5m to the device in operation. They give some suggestions to improving that, but it doesn't look like any of them were actually implemented.


Sam's Laser FAQ! Ah, the hours I spent reading through this when I was younger.


I have to admit I look back at sci.electronics.* and comp.robotics with a lot of fondness.



There have been many developments in laser technology and many updates to the page since then - check the version history (unfortunately missing dates) and you may spend a few more hours!

http://www.repairfaq.org/sam/lasersam.htm#samver


Lasers and the "Holography Handbook: Making Holograms the easy way". It had xkcd style drawings back in the 80s.


Except we called them "Forrest M. Mims" style drawings back then.

https://www.google.com/search?q=forrest+m+mims&source=lnms&t...


I've spent time on Sam's FAQ even when I was somewhat older. :)


Wow, that's a lot of different resources, and nicely organized. Speaking as a responsible hobbyist who loves to learn about these things, this is a gift, thank you.


Ctrl+F Real Genius: 0

Awww.

Kidding aside, I'm a huge fan of the text/link layout used. So effective. Thanks for showing this.


Everything except the edge-to-edge text. Put that in a container!


I love Laser Sam. I acquired some parts from the NOVA project a few years back and sent an email to Sam with some questions I had about what I had purchased. He got back to me within minutes, and was super helpful.


This is great! All I could think about was this clip from Parks and Recreation

https://www.youtube.com/watch?v=RVq10zG0UdY


Do not look at laser with remaining eye.




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