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520 pen build help

djQUAN

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How would I get it to 5mw though? It would be sweet if a weakening lense was out there. Don't acrylic lenses take 20-30% away. At 17mw it would limit it to like 11.1 or something like that.
see my post above:

I made a single mode 450nm pen running at 100+mW. Using a cardboard with a pinhole about 0.5mm diameter ('drilled' with a 1.4W in focus) inserted in the cap restricts the output power to 5mW (LPM'ed) to be safely used at presentations. Remove the restrictor for full beam visibility when used outdoors.
 

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I am more safe now. I have eye ware and everything. I'm not a total noob. My jack ass friend shined one directly in my eye on purpose. He's not even my friend anymore so it's all good.
 

Leodahsan

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Way 1: Electronics (my preferred)
Some kind of "low" mode and "high" mode? A proper PWM designed circuit, would give you the proper results. Blinking at a fast enough rate it won't be noticeable (well, kinda of)

OR

Maybe a build with a small switch (small like a dip) so you can change the current on-the-fly?

Way 2: Optics
The weakening lense you said is called a Neutral Density filter. I'd be worried about the damage threshold though.
neutral density - Free Shipping - DX

Ghetto style
DICHROS from dvd/cd burners can reflect some % of the power. Using a red dichro may reflect partially your 520nm beam, giving you lower power.

Way 3: Pinhole
See post #10
 

NKO29

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I have a smart board infront of me half the day at school. because it's a matte finish it doesnt reflect at all really. Fact is that 50mW will 99.99% not hurt anybody or cause discomfort. I have used a 1W+ 445nm inside and I was fine. (do not quote me on that, it is just a bit of an example) As long as there is no direct contact of the majority of the laser's photons to the eye, no damage will be dealt.
 

Atomicrox

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PWMing lasers doesn't make them much safer, unless you use a *very* high frequency.

OTOH I don't think it's that dangerous to use <50mW lasers to point at matte surfaces, but it would be very annoying if it's a 50mW green laser.

I think you could probably drive it low for 5mW. 20mW is definitely doable and not that annoying to look at.
 
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ive decided to just use an ebay DPSS 532nm. i know i could just say shite laser i got for 8 dollars but it sounds more cool when you call it as it is, a DPSS. i will still be building this 520 however im pushing for 80-90 mw instead of display safe.
 

Atomicrox

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You'll be hard pressed to find any safe 532nm lasers... Those pens have no IR filter and can go up to 100mW if you're "lucky".
 

hwang21

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Well some lasers have extremely divergent IR beams, some have very focused IR beams... hard to say
 

Atomicrox

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Test it out with an unfiltered camera. Cheap webcams are great for this.
 




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