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Estimate the mW of my laser?

Snipeye

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I bought it off ebay, here:

532nm 70mW Green Module w H TTL Modulation Green Laser G50 Sepcial OFFER | eBay

But I don't know if it's really 70mW, like it says. It draws 400mAh (though the TTL only takes .5 :D) at 5V, and the dot is EXTREMELY bright, right on the verge of being painful to look at. I won't stare for very long if/when I do, couple seconds tops.

When pointed directly at skin, you CAN feel it - it starts to burn a bit. Tested, and at close ranges, it can burn very small holes through black duck tape.

Any other tests I should run to try and estimate the actual output?

Thanks!
 

Lotus_Darkrose

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I'll guess it's anywhere between 1 and 100mW.

Damn you Livinloud, ya beat me! haha
 
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starlight

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Any other tests I should run to try and estimate the actual output?

Thanks!
I think you covered every imaginable idea to determine the lasers power. The only test left I can think of is using a LPM, your welcome :)
 

Snipeye

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*eyeroll* Thanks, guys, that's perfect. ;)

I know I can use an LPM, and I know that some people on the forums are willing to do that for free if I cover shipping, but I'm working with/on it now and would really rather not ship it off and wait for a week to get it back.

Ideas?
 

Lotus_Darkrose

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Roll your eyes all you want, we're still going to say to use an LPM because it's the only way to accurately measure a laser's power.

I have a green laser that is supposed to be 100mW. It could be 50mW or 150mW for all I know. I'll be buying an LPM in the next few months. Until then, I find it useless to guess on it's output because I will 100% be wrong.

EDIT:

Since it doesn't sound like you'll be getting an LPM or using another person's, This is probably the closest you'll get to your answer.

 
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DJNY

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I agree that it is veryvery hard to estimate the laserpower with higher powerd lasers.

At this power, you can do some tests:

Is it able to pop a balloon? (which color, at what distance, how long does it take)
Is it able to burn a match? (same as above)

Do divergence and beam diameter measurements.

When you did these things above, you can upload a vid here (match burning, balloon popping)and I can give you a +/- 10mW guess. Also comparing to my green lasers with similar power and the effects on balloon / match.
 

Lotus_Darkrose

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I agree that it is veryvery hard to estimate the laserpower with higher powerd lasers.

At this power, you can do some tests:

Is it able to pop a balloon? (which color, at what distance, how long does it take)
Is it able to burn a match? (same as above)

Do divergence and beam diameter measurements.

When you did these things above, you can upload a vid here (match burning, balloon popping)and I can give you a +/- 10mW guess. Also comparing to my green lasers with similar power and the effects on balloon / match.
Homework'd
 

Snipeye

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I tried - it can pop a black balloon at 2 yards in about 5 seconds, and I could not light a match (stick kind, not matchbook), even holding it almost right next to the emitter - though I did see a very faint amount of smoke. I may not have been holding it perfectly still though. Do you still need the divergence measurements?

EDIT:

Did a couple really quick divergence tests - I have a 1/4" point at about 1 foot, and that expands to roughly 3/8" at 15'.
 
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starlight

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my Dragon Lasers 75mw viper acts about the same. pops balloons but no match lighting. I have never had it metered though
 

DJNY

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You can use this tool to calculate the divergence.

Takes about 6 seconds here with a 73mW laser (1.4mRad beam diameter, 1.6mRad divergence) and a small black balloon at similar distance.

Guess you´re fine with yours, it should do around 70-80mW as well !


As some other guys pointed out, much better (not exact) measurements you can only get with one of the hobbyist sold around here.
 

Snipeye

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Excellent, thanks for the help! It's (pleasantly) surprisingly powerful for the cost - only $30. Now to do some fun things!
 

DJNY

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Wait....doesnt that mean...YOURE NOT WEARING SAFTEY GLASSES!!!!!!:scowl::tsk:
You don´t always need laser safety goggles when handling the laser with care (and you´re experienced enought to do so).

I only wear goggles when doing some beamshots, teaking LPM readings or burning stuff.
 

DrSid

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Focus it, and burn through black thin CD case. Then use formula:

Power(mw) = 1000/time(sec) (edit: more like 2000/time .. check bellow in the thread)

It's VERY rough, of course. From your description it sounds stronger then 70mW. Also 400mA is quite a lot ..
 
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