520 pen build help

[cantthinkofone]

hey guys! ive decided upon which laser i would like to use for my presentations. im going to try and get a pen kit from jayrob and a 520nm diode in copper case from DTR. is there any way i can under power it to like 5mw? i dont want to blind the people im trying to share ideas with lol. any help?

 

[NKO29]

Why would you waste $100+ on a diode that you'll only use to a tenth of it's capability ? Check the test results of the lasing threshold and that is the min you can power it before it lases.

 

[cantthinkofone]

Would 17mw cause any eyepain when just the dot is seen. No direct eye hits hopefully. Would the 17-25mw dot hurt anyone?

 

[NKO29]

As long as it doesnt directly hit anybody it will not cause damage or pain at all. but why not go with the cheaper option of a 5mw pen for presentations and have the 520nm for yourself

 

[cantthinkofone]

We are looking at maybe 5-7 presentations so it is for me

 

[NKO29]

Technically anything over 5mW? needs glasses. but if there is no chance of reflection there wont be any problem using that laser at 50mW for presentations. Most ebay lasers are at least 30mW visible + 30mW invisible.

 

[cantthinkofone]

If you know what a smart board is, that's what it will be pointed on. Extremely low chance of reflection. I've taken direct hits of 50mw visible 30 invisible and I still have good vision so although not something to risk I feel confident in it as a pointer. I might just buy an eBay pointer and make this baby a burner. No matter which one it is I AM getting one.

 

[ZRaffleticket]

For reference for everyone else, that is basically a sheet of rough plastic. It's about as reflective as white paper is.

Though an advantage of running it at a lower power might be a low wavelength, which is what everyone wants out of the green diodes.

 

[cantthinkofone]

Zraffle. Would this be even remotely safe for presentations then?

 

[djQUAN]

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.

 

[ZRaffleticket]

The 520nm at 5mW? Yeah thats perfectly fine. I would avoid the 532 personally.

 

[cantthinkofone]

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.

 

[ZRaffleticket]

Acrylic doesn't have much of an effect on lower powered lasers.

I'm not so sure what the thresholds are on the 520's but you can always mess with filters.

 

[RA_pierce]

I would just run the 520 at 50mW or so and then get a cheap 5mW 532 pointer for presentations. They are really cheap these days.

A greenie at more than 5mW will be too bright for a presentation IMO. At 20mW or so I don't think it will hurt anyone's eyes unless they are very close but it will be distracting and uncomfortable.

 

[cantthinkofone]

Okay. What could this do at 50mw? I am actually somewhat disappointed with my 100 mW 405. It's 100mw but it don't do crap. It takes FOREVER to pop black balloons and refuses to light anything. So how awesome would this be?

 

[RA_pierce]

Okay. What could this do at 50mw? I am actually somewhat disappointed with my 100 mW 405. It's 100mw but it don't do crap. It takes FOREVER to pop black balloons and refuses to light anything. So how awesome would this be?

50mW won't be much good for burning stuff. 100mW should not have a problem with balloons especially if you focus it correctly. You can probably get quite a bit more power out of the 520nm diodes but I don't know why you would want to push it to its limit unless you want to reduce it's lifetime. But you can do what you want with your diode. You should probably do some research and see what other people have tested these diodes to and make your own decision about how much power you want to get from it.

If you want to burn stuff more reliably you will need more than 100mW.

BTW if you have exposed your eyes directly to 50mW lasers, you should probably work on safety and get some decent eyewear before you get more powerful lasers because putting your eyesight at risk is just... not smart.