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What do I need to build this...

jj236

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I am interested in building a laser pointer for astronomy star pointing and bird watching/pointing (night/daylight pointer).
I have never built a laser pointer, but have some ideas where I think I might want to start...

I'm considering:
Wavelength: Green 520nm (PL520 520nm)
Wattage: Enough to be visible, don't want to burn anything. Maybe that's 35mw, 50mw, 100mw?
I would prefer something modular, so I can have future choices, but also simple.

I am considering this host, because I like the format, side button, and safety lockout:
1546058525378.png
I am considering products from this webpage: https://sites.google.com/site/dtrslasershop/home/diodes/pl520-520nm-laser-diode

Can you help me pick the appropriate products/modules for a build?
I don't know how to choose the diode, size, driver, module, etc.
What other parts/modules are needed?
Preferring quality, not super cheap.

Thank you
 



paul1598419

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If you are trying to see the spot in daylight, that can be problematic. You could easily see the spot from a 50 mW 520nm green laser at night, but in sunlight, not so much. Especially if your bird watching is in trees that are green too. I would have two lasers. One for daytime and another for night. You could get by with a red 635nm ML501P73 diode driven at 1.2 amps for daytime use, but that 301 host won't handle the amount of heat you will be getting out of it. Where did you find an empty 301 host to build in? Normally, these are sold from Chinese sellers and aren't available as empty hosts.
 

GSS

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Paul, yup these empty 301's are out there and iv'e even seen empty pen host's too.. Not cheap either, like $3 to $5???


Some 532 module sights say its a direct replacement for torch style hosts.
The only thing I can figure is you can pot the output on a replacement and know what power your getting??
 
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Lifetime17

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Hi, Your choice of the PL520 is good , Its a single mode diode with a tight beam. I built a few of them and just put together this one. Enjoy the hobby.
Rich:)fullsizeoutput_a06.jpegfullsizeoutput_a02.jpegfullsizeoutput_a00.jpegfullsizeoutput_a04.jpeg
 

brendon7358

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I would suggest just getting a cheap 532nm green pen from ebay, those are usually 50mW or more which is a all you need for star pointing. You can usually get them for a few dollars or a 3 pack for $5-$10. Or you could even get a 532nm laser on ebay in that same host you wanted to use with a battery and charger for around $10. You can try using it for birds too but I would just forget about it, even if it was bright enough to see it in the daytime you would just scare the birds away. Some companies sell lasers specifically for that purpose.
 

jj236

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For a night laser pointer, what wattage is enough? 50mw? Is 5mw too low?
What about beam diameter (easier to see a larger brighter beam for pointing)?
 

brendon7358

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Depends on wavelength. A 50-100mW 532nm is perfect. Any less might be hard to see (but probably fine down to 25mW or so) any more would be too bright and might cause you to loose your night vision.
 

jj236

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What parts would I need from DTR for a 520nm 50mw laser pointer to fit the host?
 

brendon7358

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Why not just buy one for $5-$10? Would save you a lot of money. No need to build something so simple and spend 5-10x as much. Build something you can't buy like 488nm or something.
 

paul1598419

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You could search "532nm laser pointers" on eBay and look for 301 or 303 style hosts there. You can get the laser, a cheap battery and a cheap charger for ~$10. If you tried to build it yourself it would cost you much more than that. Those 301/303 532nm lasers on eBay are all built at the same place and measure between 50 mW and 85 mW. Most of mine came in at 80 mW. They have a nice thin beam that has pretty good divergence specs and are quite visible in the night sky. If you try using one in a very cold environment, you will find they need warm up time to get to full power.
 




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