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Power Meter Calibration and Comparison

icecruncher

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danq said:
pls forgive me if this is slightly out of line...but I thought the primary purpose of  this is for each of us to be able  to calibrate our meters, so when we report a power reading later, it will be accurate... kind of like synchronizing our watches.

Of course a nice side-benefit is we will have data on different meters - and I will of course report my meter's readings before I adjust it - but then I will adjust mine to the 'standard'.

I'd like opinions on whether these basic procedural blocks are what y'all have in mind:
  • get my meter as accurate as I can, with what I've got here
  • receive the 'standard' laser(s) in the mail
  • measure the 'standard' laser's output prior to adjusting my meter
  • adjust my meter to read the standard-bearer's set value (or that of whomever is thought to have the most accurate meter so far)
  • pass the 'standard' on to the next person
  • report my measurements
  • later, when everybody has posted their results, decide whether the standard-bearer's measurement was accurate
  • if not, adjust my meter to reflect the new (computed) reading that should have been the standard reading.
sound good?
Same thing I'm wondering. I'm also curious how close all the LPM-1's are and if the 2.58x is consistent across the board or if we each need to adjust accordingly based on our meter (LPM-1 or whatever).

But, what is going to get the best results, regarding any of the power meters, IMO, is the curve for the power meter, much more than the readings. If we can plot a curve for ANY of the power meters, it would allow a fairly accurate reading at any nm freq. and it would allow comparisons between the same type of meters.

So you could have a 405nm diode and if you have the curve for the meter you can determine the power for that diode using ANY of the settings (470, 650, etc)  just by comparison and matching to the curve and not have to do the same thing when the next "new" diode comes out at a different frequency.
 

Kenom

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Ok sound off on who's

who's participating? I am.

Jayrob,
Daguin
Zom-b
IgorT (Slovenia)
Rckstr.
danq
muledeer
happytomato (Uk.)
Gooeygus.
Scopeguy
pullbangdead
electron

Unclear on Hydro, involvement or not.
 

daguin

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danq said:
[quote author=Kenom link=1217029972/120#129 date=1217442408]Ok sound off on who's participating. I am.
me.
DanQ

p.s. Jayrob, I'm in northern California too - Davis - where are you?[/quote]


PICK ME! PICK ME!!

Peace,
dave
 

IgorT

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icecruncher said:
Same thing I'm wondering. I'm also curious how close all the LPM-1's are and if the 2.58x is consistent across the board or if we each need to adjust accordingly based on our meter (LPM-1 or whatever).

But, what is going to get the best results, regarding any of the power meters, IMO, is the curve for the power meter, much more than the readings. If we can plot a curve for ANY of the power meters, it would allow a fairly accurate reading at any nm freq. and it would allow comparisons between the same type of meters.
That's a whole different experiment. How would you go about doing that?

I don't think it's gonna be possible to plot a curve inside this experiment. But at least you'll get a proper 405nm correction factor for your optical meter from all this, if you calculate it based on the most accurate thermal reading (or their average).
 

jayrob

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danq said:
p.s. Jayrob, I'm in northern California too - Davis - where are you?
Davis? Man I'm 30 or 40 minutes from you! Oakley...just over the Antioch bridge...
That's 4 of us right here in California! You, hydro, daguin, and myself!
Jay
 

hydro

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Kenom said:
Ok sound off on who's

who's participating?  I am.

Jayrob,
Daguin
Zom-b
IgorT (Slovenia)
Rckstr.
danq
muledeer
happytomato (Uk.)
Gooeygus.
Scopeguy

Unclear on Hydro, pullbanghead, and electron's involvement or not.

as it sits without the three listed above, we are at 10 participants not including me (as I won't be contributing cash but will contribute the lasers)

Sorry guy, long day at work but I'm in!
 

danq

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jayrob said:
Davis? Man I'm 30 or 40 minutes from you! Oakley...just over the Antioch bridge...
[threadjack]

Google Maps has it at 1:11, going 113 to Rio Vista then 160 to 4...

anyway now we know if there's need to ship something (laser standard) one direction or the other, do-it-yourself delivery will work! (ignoring the price of gas)

Heck, if I get back in shape I could ride my bike on most of that route. I know where to get a really bright red tail light for safety!

[/threadjack]
 

jayrob

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danq said:
[quote author=jayrob link=1217029972/120#137 date=1217476863]Davis? Man I'm 30 or 40 minutes from you! Oakley...just over the Antioch bridge...
[threadjack]

Google Maps has it at 1:11, going 113 to Rio Vista then 160 to 4...

anyway now we know if there's need to ship something (laser standard) one direction or the other, do-it-yourself delivery will work! (ignoring the price of gas)

Heck, if I get back in shape I could ride my bike on most of that route. I know where to get a really bright red tail light for safety!

[/threadjack][/quote]

Well, for sure it would make sense that for this experiment, that when Kenom figures the order of shipping, it would be you and I , then down to Dave and hydro (or vice-versa). But we are all in CA, so no matter the order, it will be quick between the 4 of us...
Jay
 

Kenom

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Ha! you bet. that's awesome. I wish I had laserists livin near me. I'm corruptin a few locals but nothing extreme like us. On another note. Billings is only 150 miles from bozeman where there are 4 major research laser labs. I'm moving down there when I start my engineering schooling as the college I'm going to now only has pre-engineering. Might have to make friends at the reseach places and have some real fun!
/threadjack/

I'll add hydro to the list here pdq (pretty darn quick). I'd say give it to the end of the weekend for others to speak up and get in line and then we'll start collecting payments.
 

GooeyGus

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Igor and I were talking via e-mail today, and I think we've come up with a decent idea.

This whole test kit could be enclosed into one small-ish box. It would be run via a dc adapter that would be included with it, which would make batteries a non-issue. Also, it would allow us to use a linear regulator which will save us a lot on costs. I can build two LM317 drivers for like $5, as opposed to $40+ for two of the lavadrives. Also, I think the drivers should use fixed resistors. Pots are just too sensitive and fragile, especially the 2mm ones used on the small drivers. Also, enclosing everything into a box would help protect the lenses from dust, since there would be a removable cover where the beam output would be. Utilizing a wall adaptor for power will also discourage people from 'playing' with the lasers outside of the test environment (YES, YOU!! ;D ). Also, we discussed a remote switch for the two lasers, so hand temp would not be a factor.

BUT, These are all just ideas. Ultimately though, in my opinion, I think one small unit that does everything without needing batteries is the best bet. Also, it would be much cheaper.
 

danq

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well, if you want to keep it failsafe, put all the power circuitry inside the box!
the typical wall adapter has a male plug, so you'd have a socket on the side of the boxx, right? Then someone sees that they have a higher-voltage wall-wart that fits in there, and maybe it would be cool to give it that extra juice...

So maybe hard-wire the wall-wart to the inside of the box? or put the thing inside the box, so there's nothing but an AC plug on the outside. Or, more lightweight: spend $3 on a tiny transformer (or cannibalize a wart), another $2 for a bridge rectumfire, and again have only an ac plug hanging out.

[added]  hand heat affect the laser source box? when it has a pair of power-dissipating regulators in there? I don't think so :-? ::)

[added again] but the box idea is good - less likely to get lost, taken on trips, dropped, etc and affords better protection if something does happen.
 




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