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My Laser In The Classroom

BobDiaz

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I haven't posted for a long while, but I've still been playing with lasers. I teach Electronics classes at the local Jr. College. For the last few years it's been frustrating because I couldn't show my lasers to anyone because I didn't have enough safety glasses. Well, that all changed when the person in charge of grant money allowed me to purchase enough Eagle Safety Glasses for all the students.

I always start with my 100mW Green Laser by lighting matches and popping balloons. Being that we are in an electronics class, I also show them the driver circuit and explain how it works.

My new laser is the 1.7W Blue Laser that's a lot more impressive. Here's the video of the first test:

https://vimeo.com/283230859


Bob Diaz
 

badboybilly

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Awesome man, a lot more laser inthusiasts are going to leave that class, That’s great,
Everyone at my job knows I build lasers and I often bring them in for show and burn, even
Though they are way overpowered! And illegal I think!
 

LewDude

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Very awesome you were able to get glasses for everyone!! I would take your class :)
 

Lifetime17

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Hi,
Thats great to show folks in a controlled environment and all safety factors involved. Good Job..

Rich:)
 

BobDiaz

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Thanks everyone. I have had 2 students build their own high powered laser from my design plans. Because there are many options and choices, I sit down with he student who plans on building a laser. The first and most important thing is the safety glasses.

I'm currently working on another laser that uses a red laser diode. The design is based on the Mitsubishi 500mW 638 Diode. (See link below) The biggest headache is there's just no way to keep the cost down. By the time you add the safety glasses and parts, the cost is reaching $100. Unfortunately many of my students are from low income families and that's a lot of money for them to pay.

https://sites.google.com/site/dtrlpf/home/diodes/mitsubishi-635nm-500mw-diodes
 

Hap

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That’s great! As others have said, make sure you always be safe. :beer: :yh:

-Alex
 

paul1598419

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Thanks everyone. I have had 2 students build their own high powered laser from my design plans. Because there are many options and choices, I sit down with he student who plans on building a laser. The first and most important thing is the safety glasses.

I'm currently working on another laser that uses a red laser diode. The design is based on the Mitsubishi 500mW 638 Diode. (See link below) The biggest headache is there's just no way to keep the cost down. By the time you add the safety glasses and parts, the cost is reaching $100. Unfortunately many of my students are from low income families and that's a lot of money for them to pay.

https://sites.google.com/site/dtrlpf/home/diodes/mitsubishi-635nm-500mw-diodes
The Mitsubishi ML501P73 is one of the cheapest diodes you can find on eBay. One thing you should be aware of, it has terrible divergence specs. As long as you press it into a 12 mm module and pair it with a 1+ amp driver, it can be a very inexpensive build for your students. You should start going further in building lasers by buying your diodes, modules, drivers and lenses separately for the best price. You can reduce the divergence to a limited degree by using as multi-element lens instead of a short focal length aspheric lens. These lenses are less expensive, but at the cost of up to 25% power loss. If you don't care about the divergence, you can buy the short FL aspheres on eBay for ~$8.00. This diode has a low forward voltage, so a buck driver works well with these diodes. No boost drivers. I have one doing a little over 1 watt with the driver set ~1.2 amps, IIRC. If you use a nickel plated brass module instead of copper, you can buy these in small quantities for ~$2.00 each. Check eBay. It can be your friend when trying to build on a budget.
 

Lifetime17

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Hi Paul,
Great information on this keeping cost down low so others can enjoy the hobby. And it's in a controlled environment with adults supervision.
Those Mitsu500's can still burn at 1W focused with a G2. I have a few and you cant kill them I like them better than the 700's

Rich:)
 

paul1598419

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Yeah, I burned up my two Oclaro 700 mW diodes just pushing them to 1 amp. I moved on to the Mits and never looked back.
 

BobDiaz

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There are a number of rules we created to keep everyone safe. First I lock the classroom door so no one could walk in without their safety glasses. Second my tool-room attendant must be present to double check that everyone is wearing safety glasses. We now have fire bricks so that the laser doesn't hit the wall and burn a mark in the paint. There is always a fire extinguisher in the room at all times. My tool-room attendant checks it every month.
 




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