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FrozenGate by Avery

[Pic Heavy] My DIY LPM!

Re: My DIY LPM!

Fretwrecker94 said:
I'll be takin some photos of it tonight! So keep on the l'll update the OP with them.
Yeah, obviously it isn't 100% accurate, but I can like with 95% ish. It seems to give a good idea of power :)
Click to expand...
No power meter is 100% accurate across it's entire range...

For example a Coherent LaserCheck has a stated NIST
traceable calibrated accuracy of +/- 5%... that is a total
accuracy of 10% for a NIST traceable LPM.

Jerry
 





Re: My DIY LPM!

Optical power is difficult to measure very precise compared to for example electrical measurements, in relative accuracy the NIST optical power standard is much less accurate than electrical standards, after a few steps down in the calibration chain you end up with +/-2.5~5% usually, sometimes better.
 
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Re: My DIY LPM!

We are measuring Optical Power with a LPM not any direct electrical
measurement.
The accuracy should reflect the Optical Power accuracy of an LPM.... IMO


Jerry
 
Re: My DIY LPM!

lasersbee said:
No power meter is 100% accurate across it's entire range...

For example a Coherent LaserCheck has a stated NIST
traceable calibrated accuracy of +/- 5%... that is a total
accuracy of 10% for a NIST traceable LPM.

Jerry
Click to expand...

True, so I probably should have said within 10% of a professionally manufactured LPM

*EDIT* Photos added!
 
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I think he ment, my what a BIG heatsink you have:D
 
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Nice job with the build. What do you think will be the maximum ammount of energy this can read out?
 
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The voltmeter maxes out at 1.999mV so its for <2W readings. I only use/build in the <350mW range due to personal taste and comfort so it works out pretty great.
 
How much more would it cost to have parts that would be able to read up to 2.5 W?
 
Well its just a matter of upgrading the Voltmeter. And if you're going 2W+ I'd also recommend upgrading the TEC. But that's just a matter of a quicker response time.

Side note, remember to add a zeroing potentiometer. I left it on the inside and am in the process of converting it.
 
pretty slick! I am going to have to build me one till I can drop $350+ on that Laserbee II...

"Off to the Drawing board!"
 
My thoughts exactly. It gets the job done for now, but I'm saving up for a professionally manufactured LPM.
 
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