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Dealextreme DX branded 5mw Laser pointer

tsk1979

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This is my first laser pointer. It says 5mW and comes in a pen host which takes 2 AAA batteries.
Since its 7$ approx, I was not too worried if its less than 5mW, however, its clearly more than 5mW.
Reasons I think so
1. Beam is visible(not very much though) in lit rooms (CFL/Tubelight).
2. Dot is clearly visible on a wall 10meters away even in bright sunlight.

Here is the link
Cheap 5mW 532nm Green Laser Pointer Pen with DX Logo (2*AAA)

The host is simple pen host, however the build quality could have been better. The AAAs rattle inside the pen, and you need to insert some paper to stop that.

I tried a video with cell phone, but beam is not visible to the cellphone camera, because its not that strong.

So I took a simple face/nasal steamer(costs 350 INR here), and shone the beam through steam
Green laser overspec 5mw with steam - YouTube

I figure I can use incense (1-2 INR a stick) too.

This laser should be about 10-15mW, but definitely not higher, as I think 30mW+ overspec lasers can actually burn stuff. This does not.

That said 10-15mW is dangerous, and I take care not to shine dot on non matt surfaces.
My primary intended use is star pointing, and the beam is highly visible at night.

I would give a definitely "recommend" rating for the price.
 

Gun

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I'd say this laser is more than 10-15mW, could be more than 30mW even. 30mW can not burn unless focused very well. There is no real way to test the power without an LPM.
 
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tsk1979

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I'd say this laser is more than 10-15mW, could be more than 30mW even. 30mW can not burn unless focused very well. There is no real way to test the power without an LPM.
Actually this worried me. Due to this I rarely shoot it indoors where it can hit a wall or something and hurt my eyes. Laser goggles should be here in a few days, so I will be more confident about using this.

About actual power, it will be great if some LPF member with meter who likes to collect cheap pens buys from DX and tests.
 

Gun

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You can shine it around inside without goggles as long as you're careful.

There is a list of members that will LPM lasers free of charge, you could find the person closest to you and get them to LPM it for you, if no one is willing to buy one.
 

tsk1979

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You can shine it around inside without goggles as long as you're careful.

There is a list of members that will LPM lasers free of charge, you could find the person closest to you and get them to LPM it for you, if no one is willing to buy one.
Since I am in India, there is nobody here :).
But I guess this is one of the most commonly sold pen lasers, somebody must be having this. I will trawl through threads and see
 

Pman

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532nm does not burn well in comparison to a 650 or 405 and therefore I usually don't mod them unless they are closer to 100mw (or have very low IR).
Gun is likely correct that your unit is stronger than you think. Better units will be brighter for same mw rating if they have low IR content. Have a 25mw 532nm with <5% IR that is very strong. The modules that come in most inexpensive pens have high IR and that is why a lot of us are always on the lookout for inexpensive low IR 532nm modules and pens such as the ones that Fasttech sells. Have yet to test any 532nm from them that has been over 10% IR.
 
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tonyt

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I'll be the guinea pig! Post the link, I'll buy one.. Lpm it and check for ir.
 

Pman

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All I meant is that if you had a 75mw 532nm and a 75mw 405 or 650nm and tried to burn a piece of black plastic, the 405 or 650 will burn better more specifically if we are talking about cheap pens.
Absolutely not saying that the 532nm won't burn. Believe this is partly due to the IR and partly to the general instability of 532nm as you may have 75mw at first but then all of a sudden it's 45. I'll have to try a burn test (not very scientific though) between a stable 532 vs. a 405/650 at as close to the same mw rating as I can get.
A shorter wavelength should burn better than a longer one so a 405 should burn better than the 532 or 650. Obviously focusing ability matters. Divergence.
Believe I have an easier time burning with a red over a green only because I can get it focused to a smaller dot and the greens at this price level tend to be very unstable with lots of IR otherwise the green should burn better all things being equal.
Notice that my input in post #7 is talking about modding pens (as I am VERY familiar with that if you take a look at my tutorial). This thread has to do with very inexpensive units.
Every 532nm laser or module I've purchased from Fasttech has <10% IR and is more stable than any other pen/module I've seen for the $ and they can burn if you set them up too:)
The big deal for cheap $5 pens that are way overspec is that if you can find a good source for them you usually get a 405nm in the 80mw range and a 650nm over 100mw every time. The 532nm tend to be all over the place. The point is that if you want to light a match as inexpensively as possible then a 405 or 650 is the way to go. The 650nm that is 128mw that I made to focus in my tutorial can light a red headed match regardless of whether it is from a matchbook or stick. 405nm burns just as good with less mw from my experience with these units.
 

Leodahsan

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All I meant is that if you had a 75mw 532nm and a 75mw 405 or 650nm and tried to burn a piece of black plastic, the 405 or 650 will burn better more specifically if we are talking about cheap pens.
Absolutely not saying that the 532nm won't burn. Believe this is partly due to the IR and partly to the general instability of 532nm as you may have 75mw at first but then all of a sudden it's 45. I'll have to try a burn test (not very scientific though) between a stable 532 vs. a 405/650 at as close to the same mw rating as I can get.
A shorter wavelength should burn better than a longer one so a 405 should burn better than the 532 or 650. Obviously focusing ability matters. Divergence.
Believe I have an easier time burning with a red over a green only because I can get it focused to a smaller dot and the greens at this price level tend to be very unstable with lots of IR otherwise the green should burn better all things being equal.
Notice that my input in post #7 is talking about modding pens (as I am VERY familiar with that if you take a look at my tutorial). This thread has to do with very inexpensive units.
Every 532nm laser or module I've purchased from Fasttech has <10% IR and is more stable than any other pen/module I've seen for the $ and they can burn if you set them up too:)
The big deal for cheap $5 pens that are way overspec is that if you can find a good source for them you usually get a 405nm in the 80mw range and a 650nm over 100mw every time. The 532nm tend to be all over the place. The point is that if you want to light a match as inexpensively as possible then a 405 or 650 is the way to go. The 650nm that is 128mw that I made to focus in my tutorial can light a red headed match regardless of whether it is from a matchbook or stick. 405nm burns just as good with less mw from my experience with these units.
It depends on material reflection on that specific wavelength. If both lasers have same power (and are stable, but lets just talk about diodes here) and power density, both should burn equally, right?

What proves that is our method for measuring lasers. The LPM is a "calorimeter".

IMO DPSS green should burn better (if it is stable), because the beam diameter @ aperture is very smaller than a laser diode @ aixiz lens.

PS: I'm not bashing ok?
 

Pman

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I can agree with that. Problem is there's just so many variables and it's VERY hard to get an exact match to test. Power is power regardless of anything else. In general a lower wavelength and smaller beam diameter wins.
Honestly wish I had never said anything about it at this point. The discussion on this can turn neverending.
Too many variables.... and I know you're not bashing:) Hard to give a simple answer when you are dealing with apples and oranges. Again, power is power regardless of nm.
 

Leodahsan

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Agreed. I just started that discussion because some time ago, I've read someone saying that 405nm burns better than 660nm, because 405 has more power in its photons, etc... Yeah that person was right, but more power / photon = less photons... so the optical output is the same.

:beer:
 




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