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Need help

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afandjegudiel

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My little brother decided to build a burning laser for the science fair, and with a little persuasion at school, we got the permission as long as I'm there to supervise. But, we need a little help with the building. We have two or three old dvd burners lying around, and we ordered a blank aixiz housing off the internet. where do we go from here? doesn't have to be fancy, just pop a balloon and light matches.
 





A

afandjegudiel

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I have a mag-lite that I bought specifically for this project, but it seems that all the diodes I have ready for harvest are class 1. Will that do the trick, or am I going to have to order a more powerful one online?
 
laserboystuart

laserboystuart

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it will say 'class 1 laser product' on the dvd burner because the diode is not exposed, as long it is a 16x dvd burner or more you will get a fair amount of power.

but do not, for the love of god use a maglite without a driver. lemme' guess... kipkay, he is an idiot!

jayrob has some maglite kits that are machined to fit a driver, drop him a line if you want a long lasting diode.
 
BShanahan14rulz

BShanahan14rulz

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Or even cheaper, build your own driver using an LM317 chip. These are a common, easy-to-use regulator that can be set up to provide constant current. Do a search for DDL, LM317, eventually you'll find a nice, easy to read schematic. All parts are available at the radiohut. Plus, when the teacher asks you "what's this bit do?" you can say "well, the electricity flows through this chip, through these resistors that set the current" blah blah blah.

One thing you should keep in mind is safety. A laser that can burn is fairly dangerous to the vision. You know how if one of those cheap-o <5mW red lasers from gas stations leaves a blind spot on your retina for a few minutes if it glances your eye? Results of this laser glancing or reflecting into someone's eye will be much worse.
You can get laser goggles for you and everyone observing, but that can get costly (for some reason, red-blocking goggles seem to be more expensive than the ones that block green and blu-ray). You could also just get a few pairs, just for whoever is presenting, and put in a few safety features like a beam terminator and a steady mount for the laser, and a "wall" (made from anti-laser goggles) in front of where you would be burning something. Dag, now you have me thinking of ideas for this. I'll draw an MSPaint pic for ya.

edit:
laserSciFai.jpg


so, imagine a hole in the pane, laser goes through it so nobody can see the final spot, and when you are actually burning something, people can only observe through the goggles set up in front of the focal point.

Basically, just be safe about this. It can be dangerous, but it can also be very interesting. Perhaps next year or the year after, you can do a project about DPSS lasers ;-)
 
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Morgan

Morgan

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Hey,

Your problem here will be the amount of people you can safely, 'display', to. Even though the suggestion above may be safe if closely controlled, I'm sure a science project of this kind will score more highly with better protection.

Check out the, 'Safety and Legal Issues', section. This will give you much better, concise info than this thread. Any exposure, however small, can result in damage and the hazards need to be understood.

To be sure, restrict the viewers to only those wearing suitable eye protection and those ONLY! Do the display lots of times if necessary. Eye safety is essential and should not be compromised to get a larger audience.

Stay safe.

M
:)
 
laserboystuart

laserboystuart

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im sure that you will get a couple of extra marks for your science fair project if your teachers/judges know that you understand laser safety and have taken that on board, listen to morgan, eye protection is definitely needed unless you want everyone to go home with spots on their eyes from exposure of the bright dot.

stuart :)
 
A

afandjegudiel

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Thanks for all the amazing advice. And, yeah, Kipkay. I've actually abandoned that idea in favor of building a driver myself and putting it in a flashlight case.
Also, safety IS something I've been thinking about more as I learn more about the laser. If I were to put the laser in a box with a hole at the far end aimed toward what we're burning, would that be safe enough? Or, would the beam still be dangerous without some sort of eyewear? Afterall, I think I may have a hard time buying enough safety goggles. This would also cut down on the crowd control aspect.
 
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Morgan

Morgan

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There are many factors to how safe any laser is. Just pointing it away from the audience doesn't mean it is automatically safe. Reflected light can also be hazardous.

This is a difficult area for me to advise you on but there are plenty of people here who can. I know I am safe when I use my lasers because I'm sad, without any friends and therefore only need to look after my own eyes with the correct protection I bought for them.

When it comes to public displays there are numerous legislations, recommendations, guidelines and must dos. There was a thread I read recently with some excellent references: http://laserpointerforums.com/f53/my-eyes-my-eyes-48440.html . (LSRFAQ is an expert in this sort of thing and he has some very good points to make in this thread!)

I don't want to rain on any parade but you just can't afford to cut corners on this. However, if you go about things in the right way then you should still be able to achieve a good showable project. Look on the plus side too, if you could only show 2 or 3 people at a time, you will have a good long presentation with not much to say if you have to say it 10 times!

Happy reading...

M
:)http://laserpointerforums.com/f53/my-eyes-my-eyes-48440.html
 
A

afandjegudiel

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Right. Know of any retailers that carry the goggles? I just did a google search and came back with nada. Just wanna be sure where I can or cannot get them.
 
BShanahan14rulz

BShanahan14rulz

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perhaps by the time you buy enough goggles, it will have been more cost effective to get a custom made square sheet of shielding plastic?
 
A

afandjegudiel

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Shielding plastic? I just googled, and I still don't know quite what that is, let alone where to get it.
 
A

afandjegudiel

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Okay, so now we have a couple of pairs of goggles. However, upon harvest of my diode, I discovered that it was burnt out. So, I ordered one online and thought I'd shoot for the stars and grab a blu-ray. Now I have it and I can't figure out how to set up the DDL driver, since it says on the diagram that values differ for blu-ray.
I tried to figure it out with the equation... But, I just ended up scratching my head going "what does that mean?" I think what I got was 13.9? How do I set that up?
I'm beginning to feel like I got in over my head when we decided to do this.

.:Edit:. Nevermind, I paid more attention to the page... Yup, take away one resistor... Thanks anyway, though.
 
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