Calibration Lasers for LPMs

Wolfman29 · Oct 25, 2011

So I had this idea after seeing the thread in the Buy/Sell/Trade forums....

Why hasn't anyone made any cheap calibration lasers for DIY and other LPMs?

I feel like it could be significantly cheaper than either sending it back for calibration or for buying an LPM to calibrate against. I figure the kit would be as simple as using a PHR and an LPC both set at exactly 100mW each... then, just shine each one on your thermal/optical target and calibrate accordingly....

And because it could as simple as being in a project box or something, these could probably be produced for around $20-25, and, for the effort put in for adjusting the outputs to get exactly 100mW on a calibrated LPM, they could probably be sold for $35 or so and still make a decent amount of money....

So is there something I am missing? I have a feeling that these would be extraordinarily popular amongst those of us who built our own LPMs.

bennett326 · Oct 25, 2011

Well they have to be stable as hell.... That's the only thing I can think of

Wolfman29 · Oct 25, 2011

Diode lasers are generally very stable in output, and especially at these low powers, minimal heatsinking will be required, so they should be fairly stable for about a minute at least and then they may need a cool down. Point being, I think it's doable. :thinking:

ARG · Oct 26, 2011

Mario Master said in another thread that he used a stable TEC regulated IR laser.

InfinitusEquitas · Oct 26, 2011

Wolfman29 said:
Diode lasers are generally very stable in output, and especially at these low powers, minimal heatsinking will be required, so they should be fairly stable for about a minute at least and then they may need a cool down. Point being, I think it's doable. :thinking:

I think you could get in the ballpark, but not spot on, because different batteries and even ambient temperature will affect the output somewhat.

Considering a margin of ~10% is acceptable for hobbyist LPM's, it's an interesting idea though.

Wolfman29 · Oct 26, 2011

But see, even that would be unnecessary. As long as it isn't on long enough to overheat, diode lasers are stable (as long as the driver is stable, which it's easy to make one).

EDIT: @IE: I think that if someone made it a plug-in module, it would be easily doable AND stable (with exception of the ambient temperature). But remember, the point of this ISN'T to make something that is the highest of high quality - just something stable for about a minute, so that they can be calibrated. If it was too complex, it wouldn't be worth it to not buy another LPM or get it "professionally" calibrated.

kiyoukan · Oct 26, 2011

Well first sometimes you want several nm of lasers just to make sure the coating you used is good.
if there is enough interest i would be willing to build a set of 3 lasers 445nm 532nm 650nm, someone would have to supply the green.
But this would be a trade item.
you send 50$+shipping the setup is sent to you and once you calibrate you send it back and you get 40$ back.
but imho its better to send the whole meter out to be calibrated as it only takes around 5min max to calibrate.
or do what i did for mine take 10 445nm lasers all at the same power and powered from a wall psu and record there power levels then average them and find the one that was nearest the average and call it.
minus any outliers like one was doing 1.3W at 1a and another was doing 872mw at 1a but most of them ranged around the 1w mark
Not the best way to calibrate a meter but i think it works.

Wolfman29 · Oct 26, 2011

Well, I would like to think that if the coating for 405 and 650 are good, then the coating for 532 would be in line, considering the fact that it lies between the two.

But that's an interesting idea... not selling them, but just doing a collateral system to give it out for free, essentially. If you don't do it, I will - I wouldn't mind it.

kiyoukan · Oct 26, 2011

my problem is i need a cheap green the collateral must be the same price as the material so if a member decides to keep it we dont lose money
i was going to say 445nm but the price would be to high.

lasersbee · Oct 26, 2011

The idea was already attempted by Kenom quite a while
back... There is a spread sheet somewhere on the results...

A set of (supposedly stable Lasers of different wavelengths
were shipped all over to test the validity/accuracy of LPMs
used by LPF members...
There were problems with the Lasers... but still a valiant
try.

We use a Lab quality Laser Diode Driver to adjust the current
of our test Lasers when we calibrate our LaserBee Products.

We have found that ambient temperatures (and perhaps other
factors) can cause an LD current change to get the same optical
power output from one day to the other...

We first set a test Laser to the required optical output measured
on a Lab quality LPM and then within minutes calibrate our LaserBee
LPMs to that measured power...

From one testing session to the next the output of a Laser will not
necessarily be the same at the same current. There are a lot of
outside parameters that are involved.

Jerry

Don't Laze Me Bro · Oct 26, 2011

lasersbee said:
The idea was already attempted by Kenom quite a while
back... There is a spread sheet somewhere on the results...

A set of (supposedly stable Lasers of different wavelengths
were shipped all over to test the validity/accuracy of LPMs
used by LPF members...
There were problems with the Lasers... but still a valiant
try.

We use a Lab quality Laser Diode Driver to adjust the current
of our test Lasers when we calibrate our LaserBee Products.

We have found that ambient temperatures (and perhaps other
factors) can cause an LD current change to get the same optical
power output from one day to the other...

We first set a test Laser to the required optical output measured
on a Lab quality LPM and then within minutes calibrate our LaserBee
LPMs to that measured power...

From one testing session to the next the output of a Laser will not
necessarily be the same at the same current. There are a lot of
outside parameters that are involved.

Jerry

So you do the same thing as the other LPM makers? :crackup: not that special. :na:

-D

lasersbee · Oct 26, 2011

Don't Laze Me Bro said:
So you do the same thing as the other LPM makers? :crackup: not that special. :na:

-D

So... what's your point.... :thinking:
or are you just TROLLING again....:thinking:

Jerry

kiyoukan · Oct 26, 2011

hey jerry would you mind calibrating some lpms for me?
im almost done build a diode binning rig for my 445nm diodes that will be able to temp monitor the laser diode and ambient air and make corrections but my LPM will need to be tuned.
Its a nifty setup that all you have to do is drop the LD into the diode socket and press the plunger into heat-sink and its setup to point straight at the sensor.
Thinking of adding a basic NM detection but its hard to design one accuracy of 2nm

Don't Laze Me Bro · Oct 26, 2011

lasersbee said:
So... what's your point.... :thinking:
or are you just TROLLING again....:thinking:

Jerry

I troll less than you do, sir. :tsk:

-D

bennett326 · Oct 26, 2011

i think this is stupid obviously the :na: enforced the fact that he was getting your goat..

fights are only funny some times and most of them are when TJ is expertly trolling someone and its enjoyable to read

these are not and get old the ongoing business rivalry is childish and unnecessary
IMHO no one is to blame you both troll each other. its quite obvious and once again childish take it somewhere else. like the wicked forum LOL

Don't Laze Me Bro · Oct 26, 2011

bennett326 said:
i think this is stupid obviously the :na: enforced the fact that he was getting your goat..

fights are only funny some times and most of them are when TJ is expertly trolling someone and its enjoyable to read

these are not and get old the ongoing business rivalry is childish and unnecessary
IMHO no one is to blame you both troll each other. its quite obvious and once again childish take it somewhere else. like the wicked forum LOL

You only wish you could troll like us old PROs

It is my main goal in life to troll Jerry, and he knows that :eg:

-D

Calibration Lasers for LPMs

Wolfman29

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ARG

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kiyoukan

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lasersbee

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Don't Laze Me Bro

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