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*UPDATE* Problem found LPM or Laser

Re: Am I doing this right?

Not that I'm an expert on LPMs in particular, but I'd expect there to be a significant degree of inaccuracy in cheaper LPMs without super frequent calibration. I've seen the real $$$$ ones in a lab, and they've got a lot going on to keep consistent temperatures on the probe. They also have super stable labbies to calibrate. Don't know what Gray has, but it'd definitely make a difference if he had another laserbee.

It'd be interesting to see exactly how much of a difference the surroundings make on readings. Maybe get a cold glass of ice water to put against the rear of the LPM for an experiment. :thinking:
 





Re: Am I doing this right?

Rivem said:
Not that I'm an expert on LPMs in particular, but I'd expect there to be a significant degree of inaccuracy in cheaper LPMs without super frequent calibration. I've seen the real $$$$ ones in a lab, and they've got a lot going on to keep consistent temperatures on the probe. They also have super stable labbies to calibrate. Don't know what Gray has, but it'd definitely make a difference if he had another laserbee.

It'd be interesting to see exactly how much of a difference the surroundings make on readings. Maybe get a cold glass of ice water to put against the rear of the LPM for an experiment. :thinking:
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Yeah, that's why I suggested waiting for another laser or two. Testing one laser is an insufficient sample size to determine if the meter is properly set up.
 
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Re: Am I doing this right?

^Thanks guys.

I'll try the test again tonight and see what I get. I'll tell Gray about it :)

-Alex
 
Re: Am I doing this right?

Take a look at their YouTube channel, it looks like they use at least 3 different LPMs, their measurements may be off a little sometimes, it looks like they place the laser quite close to the sensor. Here are some of their videos.





Alan
 
Re: Am I doing this right?

My bet is your LPM is off and his reading is correct. I have both types of LPMs. I am very concerned as to the reason why your laser is dropping so quickly in output. Are you absolutely certain the battery is fully charged and is a good cell? There's no way you should be dropping output like that unless something is wrong.
 
Re: Am I doing this right?

Gray said that the diode used in the 1W version of 650nm Lasers is also used in this one. So this is a diode capable of 1W...

I'm going home to do the test :) and will post a video!

-Alex
 
Re: Am I doing this right?

Hap said:
Gray said that the diode used in the 1W version of 650nm Lasers is also used in this one. So this is a diode capable of 1W...

I'm going home to do the test :) and will post a video!

-Alex
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Ah.. that would explain the square beam profile. I kinda thought it was weird for a 150mw red to be multi-mode, but that explains everything. I wonder if the higher power version is exactly the same with a pot turned up on the driver, or if it has a different driver entirely.

Btw what kind of battery are you using with this? I have some chinese 18650's that are really bad and make anything I put them in seem underspec. I suspect they might be fakes with smaller batteries hidden inside of them. If I put them in my O-like 2W 450nm it will hardly burn anything. When I put in quality batteries the thing will light paper on fire.
 
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Re: Am I doing this right?

Razako said:
Ah.. that would explain the square beam profile. I kinda thought it was weird for a 150mw red to be multi-mode, but that explains everything. I wonder if the higher power version is exactly the same with a pot turned up on the driver, or if it has a different driver entirely.
Click to expand...

I hope it's more of a difference than that considering the price difference.
PL-E Pro 650nm RED Laser 100mw and 1000mw

Alan
 
Re: Am I doing this right?

Razako said:
Ah.. that would explain the square beam profile. I kinda thought it was weird for a 150mw red to be multi-mode, but that explains everything. I wonder if the higher power version is exactly the same with a pot turned up on the driver, or if it has a different driver entirely.

Btw what kind of battery are you using with this? I have some chinese 18650's that are really bad and make anything I put them in seem underspec. I suspect they might be fakes with smaller batteries hidden inside of them. If I put them in my O-like 2W 450nm it will hardly burn anything. When I put in quality batteries the thing will light paper on fire.
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Hello Razako,

I am using an Efrest 18650 3400mAh battery :)

Currently charging it back up to 100%, and not running any A/C and letting the LPM on for 20mins first.

-Alex
 
Re: Am I doing this right?

Ok, here we go. LPM was set for 20mins, batteries 97% charged.

*sigh* :(



-Alex
 
Re: Am I doing this right?

Hap said:
Ok, here we go. LPM was set for 20mins, batteries 97% charged.

*sigh* :(



-Alex
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Try with a big glass of cool water behind the LPM just to see what happens. It doesn't have to touch, just be nearby.

I know it kinda sucks not having the power you were told, but keep in mind that you have a way higher quality laser than LPM, so you might want to trust one more than the other. You're going to have to see how the LPM performs on other lasers that are of a more certain power before you jump to conclusions.
 
Re: Am I doing this right? *Video Posted*

I don't focus my laser output to infinity or to a tiny spot when using a LPM, I defocus it so the spot size fills about 75 percent of the sensor surface size. This keeps from damaging the surface, if using higher power lasers. Also, put some kind of thermal insulator between the table and the aluminum of the sensor, that will throw the measurement off, maybe a piece of styro foam or something else which won't transfer heat to the table very efficiently would work. Of course, zero the meter with it sitting on the styrofoam, or what have you.
 
Re: Am I doing this right?

Razako said:
Ah.. that would explain the square beam profile. I kinda thought it was weird for a 150mw red to be multi-mode, but that explains everything. I wonder if the higher power version is exactly the same with a pot turned up on the driver, or if it has a different driver entirely.

Btw what kind of battery are you using with this? I have some chinese 18650's that are really bad and make anything I put them in seem underspec. I suspect they might be fakes with smaller batteries hidden inside of them. If I put them in my O-like 2W 450nm it will hardly burn anything. When I put in quality batteries the thing will light paper on fire.
Click to expand...

Rivem said:
Try with a big glass of cool water behind the LPM just to see what happens. It doesn't have to touch, just be nearby.

I know it kinda sucks not having the power you were told, but keep in mind that you have a way higher quality laser than LPM, so you might want to trust one more than the other. You're going to have to see how the LPM performs on other lasers that are of a more certain power before you jump to conclusions.
Click to expand...

Ugh. So there is a chance the LPM might be faulty? I heard Laserbee's were pretty good, no?

:(

-Alex
 
Re: Am I doing this right?

Hap said:
Ugh. So there is a chance the LPM might be faulty? I heard Laserbee's were pretty good, no?

:(

-Alex
Click to expand...
Potentially. Unfortunately it's hard to tell unless you have a bigger sample size. I'm rather conflicted here actually. On one side I've heard good things about laserbee LPM's. On the other I don't understand why jetlasers would produce and send out an underspec red. The thing uses a 1 watt capable diode and there would be no financial incentive to send out underspec units.
 
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Re: Am I doing this right?

Razako said:
Potentially. Unfortunately it's hard to tell unless you have a bigger sample size. I'm rather conflicted here actually. On one side I've heard good things about laserbee LPM's. On the other I don't understand why jetlasers would produce and send out an underspec red. The thing uses a 1 watt capable diode and there would be no financial incentive to send out underspec units.
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Indeed!

I've sent Gray a email with this video. I should be getting my 30mW 589nm next week. If it too outputs less then 30mW something is wrong with this thing. If it outputs 30mW or over then it's the laser! :mad:

-Alex
 
Re: Am I doing this right?

Hap said:
Ugh. So there is a chance the LPM might be faulty? I heard Laserbee's were pretty good, no?

:(

-Alex
Click to expand...

Don't get me wrong. They're almost certainly the best new meter you can get for the money. I'm not sure what their quality's like since I don't have one, but they're clearly a far cry from the lab grade stuff that can almost guarantee a power level with precision and accuracy. The correction algorithms in the software of newer meters like that will also be pretty complex. Of course, you could probably buy 15-20 very nice lasers for the price of one of the lower end ones.

Edit: Try what I said with the glass of water. It should give an idea of how the meter is corrected when you zero it.
 
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