Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



[Pic Heavy] My DIY LPM!

lasersbee

Well-known member
Joined
Sep 20, 2008
Messages
17,632
Points
113
Re: My DIY LPM!

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 :)
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
 



Bluefan

New member
Joined
Aug 15, 2009
Messages
1,482
Points
0
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.
 
Last edited:

lasersbee

Well-known member
Joined
Sep 20, 2008
Messages
17,632
Points
113
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
 

Fretwrecker94

New member
Joined
Mar 22, 2011
Messages
796
Points
0
Re: My DIY LPM!

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

*EDIT* Photos added!
 
Last edited:

eytyxhs

New member
Joined
Nov 3, 2010
Messages
2,077
Points
0
Very nice Job :beer:

Next time try with bigger TEC Heatsink.
 

n2stuff

Active member
Joined
Nov 4, 2011
Messages
812
Points
28
I think he ment, my what a BIG heatsink you have:D
 
Last edited:

The Baron

New member
Joined
Mar 26, 2012
Messages
949
Points
0
Nice job with the build. What do you think will be the maximum ammount of energy this can read out?
 
Last edited:

Fretwrecker94

New member
Joined
Mar 22, 2011
Messages
796
Points
0
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.
 

The Baron

New member
Joined
Mar 26, 2012
Messages
949
Points
0
How much more would it cost to have parts that would be able to read up to 2.5 W?
 

Fretwrecker94

New member
Joined
Mar 22, 2011
Messages
796
Points
0
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.
 

LEDSanders

Member
Joined
Nov 23, 2011
Messages
172
Points
18
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!"
 

Fretwrecker94

New member
Joined
Mar 22, 2011
Messages
796
Points
0
My thoughts exactly. It gets the job done for now, but I'm saving up for a professionally manufactured LPM.
 




Top