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Registered Member #2063
Joined: Sat Apr 04 2009, 03:16PM
Location: Toronto
Posts: 352
y are they so cheap compared to other lasers? are they a scam or they just beak easily? should i buy a laser from dealextreme or just save up for a expensive 1
Registered Member #3263
Joined: Sat Oct 02 2010, 04:43AM
Location: Sydney, Australia
Posts: 34
They generally work fine, and represent good value, but they ARE cheaply made.
The higher power ones are likely to be driven over-spec, and will require ample heat sinking.
Also, be aware that cheapy green modules wont contain an IR filter, and can be more dangerous than their apparent brightness and rating. You can check this for yourself:
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
I've bought cheap 5, 50 and 100 mW green laser pens and none had an infra red filter. The 5 mW causes instant 'blink' reaction from 10m so should be almost safe, I dared not try blink reactions with the 50 or 100 mW pens- the beams are so bright that you'd have to be much braver/stupider than me to even consider it near your eyes.
Registered Member #1334
Joined: Tue Feb 19 2008, 04:37PM
Location: Nr. London, UK
Posts: 615
Sulaiman wrote ...
I've bought cheap 5, 50 and 100 mW green laser pens and none had an infra red filter. The 5 mW causes instant 'blink' reaction from 10m so should be almost safe, I dared not try blink reactions with the 50 or 100 mW pens- the beams are so bright that you'd have to be much braver/stupider than me to even consider it near your eyes.
Just had my left retina welded (deliberately) (250 times) by a 200mW Argon (532nm) green laser.
Registered Member #2063
Joined: Sat Apr 04 2009, 03:16PM
Location: Toronto
Posts: 352
but how long do they last? i have a friend that bought a 50mW green laser from dealextreme and he said it was crap cuz the output drops to about 50% after a few seconds. and are high power green laser just a pot-modded version of the low power one?
Registered Member #27
Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058
The quality is good for the price. The $8.8 20 mW dealextreme module is reliable but has plenty of IR output. The higher power ones need low duty cycle or good cooling.
A 20 mW green laser with IR output is not a safe toy and can cause permanent eye damage.
Registered Member #2261
Joined: Mon Aug 03 2009, 01:19AM
Location: London, UK
Posts: 581
Sulaiman wrote ...
I've bought cheap 5, 50 and 100 mW green laser pens and none had an infra red filter. The 5 mW causes instant 'blink' reaction from 10m so should be almost safe, I dared not try blink reactions with the 50 or 100 mW pens- the beams are so bright that you'd have to be much braver/stupider than me to even consider it near your eyes.
5mW of green is fairly safe, but if there's no IR filter you'll find vastly larger amounts of infra red at 1064nm and 808nm. A 5mW green laser without infra red filter would be particularly dangerous because you'll think there's virtually no hazard. By the way, I saw a video of Jeri Ellsworth aiming a green laser through a Silicon Wafer towards a video camera. enough infra red got through the wafer to be visible when pointed directly at the camera.
Registered Member #2919
Joined: Fri Jun 11 2010, 06:30PM
Location: Cambridge, MA
Posts: 652
If you're lucky, cheap Ebay lasers will be overspec. My "5mW" pointer produces as much light as my 20mW Coherent Compass. Some of the Ebay pointers are only $5, so you really have nothing to lose (other than an eyeball or two if you are silly enough to point the thing into your eye )
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cheap laser from dealextreme and ebay
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