Where to buy power meter

Cyparagon said:

Thanks. It doesn't even need to be a diffraction grating, it can be anything that will remove a portion of the beam be it glass, beam splitter, or safety glasses. Also, checking the power before and after a lens or safety goggles will give the visual transmission.

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Yes anything that would attenuate the beam would suffice I suppose. About the goggles: I've read here that shining a laser directly through your goggles will make the protective function on that spot deteriorate. You aren't afraid of that?

How much did the lasercheck cost for you, Cyparagon?

I don't remember exactly, somewhere between $350 and $400.

Petrovski said:

Yes anything that would attenuate the beam would suffice I suppose. About the goggles: I've read here that shining a laser directly through your goggles will make the protective function on that spot deteriorate. You aren't afraid of that?

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That's why you check at a low setting.

Zom-B said:

That formula works only when... the laser is variable and not battery powered.

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There aren't too many battery powered lasers over a watt anyway, and just about any >1W laser is variable.

god damn those power meters are so expensive? Isn't there a custom-made way of approximating the power of your laser (doesn't have to be portable, quick, readily available all the time, or other stuff)?

Read this thread: http://www.laserpointerforums.com/forums/YaBB.pl?num=1200112201

You can't build that anymore, there aren't anymore heads left.

daguin said:

I have a 374 on it's way, but my second calorimeter (38-1UV5) isn't going to work out with it.

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OK. Sometimes I just have a brain fart. The meter is a 364 NOT a 374. The 38-1UV5 calorimeter works wonderfully with a 364, I had to get an adapter because the style of the plug changed, but all is cool with it now (better than cool). Anyway, heres a link to the "For Sale" posting,

http://www.laserpointerforums.com/forums/YaBB.pl?num=1211929115

Peace,
dave

OK, this is a little bit beyond me on how to build it, not because I'm not interested, but because I think I lack the necessary electronics background.

What is the principle of operation of a light meter? It uses a photodiode or something similar, doesn't it? Since a LED can also act as a photodiode (I tested this myself), can't you just use a LED, and shine whatever light on it and measure the mV's (often over 1V)? I did a few tests with a spare green LED, it required complete darkness to achieve 0.0mV (which implies it's quite accurate), and when I shine a lamp on it it can give 1.4 volts or more. It doesn't detect IR light, but an IR diode does (I tested this as well). I'm not sure what LED detects what light, but I would assume that it detects (peak sensitivity) whatever light it emits. The mV should be proportional to the mW of light received, so maybe this can be a good way to tell the approximated power of your laser.

I don't have a laser right now (old ones broke, waiting for new ones), but if you have:

2 same colour lasers (different power)
A power meter
A LED of the exact wavelength of the lasers
A voltmeter,

could you make a test on how accurate results this method gives? Like, shine one laser on the LED, get the mV/mW, then calculate how many mV the other laser should give (assuming they are proportional), then test the other laser.

Maybe this method doesn't have too many mW range, but it can be done

What about this?

http(colon)//cgi(dot)ebay(dot)com/120mW-Pre-Calibrated-Laser-Power-Meter-Sensor-Module_W0QQitemZ160244519927QQihZ006QQcategoryZ14954QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

For $25 it looks legit... Well, kind of.

EDIT: Forgive me about the link, had to get past the filter. Hope that's ok.

Xombie said:

What about this?

http(colon)//cgi(dot)ebay(dot)com/120mW-Pre-Calibrated-Laser-Power-Meter-Sensor-Module_W0QQitemZ160244519927QQihZ006QQcategoryZ14954QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

For $25 it looks legit... Well, kind of.

EDIT: Forgive me about the link, had to get past the filter. Hope that's ok.

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If you do a search in this forum you will find that these units got less than favorable reviews.

But, as we said in the 60's, "If it makes you feel good . . . .Do it!"

Peace,
dave

I just picked me up a scientech 373 and am waiting for the head, 38-0101 to arrive.

Oh and daguin is correct those meters suck donkey ...

Kenom said:

I just picked me up a scientech 373 and am waiting for the head, 38-0101 to arrive.

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It will be nice to hear somebody else's experience with a volume absorbing calorimeter.

Peace,
dave

Xombie said:

What about this?

http(colon)//cgi(dot)ebay(dot)com/120mW-Pre-Calibrated-Laser-Power-Meter-Sensor-Module_W0QQitemZ160244519927QQihZ006QQcategoryZ14954QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

For $25 it looks legit... Well, kind of.

EDIT: Forgive me about the link, had to get past the filter. Hope that's ok.

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Looks legit,wish they had more a version for more powerful lasers.

"looks" can be decieving.

Kenom said:

"looks" can be decieving.

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The only way to make sure is buying a real power meter to test this one,if I'm buying this one is because I don't have the money to a professional power meter(or don't want to spend the money on it),and who already has a good one,won't spend more in one without knowing it's works fine,so we will never found out if it it's precise or not

What about the method I said? Hasn't anyody tried it?