Miloš Custom Blu-Ray 25mW Laser

Re: Milos Custom Blu-Ray 25mW Laser

knimrod said:

The sensor head used in Kenom's meter and in the DIY meter looks typical of Coherent's broadband thermopile coating. It's supposed to be spectrally flat from 190-11,000nm. Coherent does offer a different coating for excimer lasers with a flat response from 150-1000nm. All my DIY probes track with my Coherent 210 probe at 405nm.

For what it's worth, I've received 2 different type of sensor heads with the surplus PCB assemblies. One type has disc with a coating that's a slightly lighter color than the other. It also has 8 screws securing the disc instead of 6. There doesn't seem to be any perceptible difference in the response though.

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Now this is why I joined this forum... A big "Thanks" to everyone for your knowledgeable input! [smiley=thumbsup.gif]

The specs on this sensor are the missing link in understanding this, or at least achieving a legitimate baseline for testing. In the next few days I'll make a video regarding the sensitivity aspect as well. I honestly believe that once stabilized in a temperature-constant environment it can be quite accurate and responsive to small changes. Knowing that the sensor coating is effectively a constant, regardless of wavelength, gives me much more faith in the readings I'm seeing. I'll pick up some alligator-clip leads for my Multimeter and maybe Milos and I can figure out what's happening in this amazing little Blue-Ray of his.

Cheers, CC

Re: Milos Custom Blu-Ray 25mW Laser

First off, I will be more than glad to walk you through measuring battery current draw of your laser. Contact me when you are ready and we can do it together over pm or even over the phone.

I have only one unit at my house now, and it is a 10mW avg. unit set at 39-40mA tested with dummy load originally multiple times as all my lasers. I just measured current battery draw with laser diode and it is 44mA. As Drlava said, measuring current at this place (by battery) is slightly higher. All of my procedures are tested multiple times and with different batteries. I use 4 batteries. Two somewhat drained, and two brand new fresh ones when testing every laser I build. Brands are DuracellProcell, and GP Greencell. Results of my measurements are extremely consistent between different lasers powers vs current and Coherent LaserCheck meter.

Anyhow, as I said, we will get to the bottom of this.
I agree its either a freak laser diode thats outputting 28mW all of a sudden and not giving up this world, or a freak laser sensor meter that doesn't like 405nm.

Whats the longest times you ran the test CC?

cheers

Milos

Re: Milos Custom Blu-Ray 25mW Laser

I as well am curious as to the issue going on here. I know that both pseudo and lava have both tested these heads against a thermal laser meterspecifically calibrated by coherent. There really is no other way than to take the laser and meter to laserglow or one of the other laser retailers close to you and have it tested from other meters.

Re: Milos Custom Blu-Ray 25mW Laser

Hi Milos, The longest I've run it is 2 minutes. When cold it usually ramps up to 28mW then settles down to 25-27mW for the remainder. If you have Skype we could videoconference that way. I've just soldered some mini-clips onto a second pair of Multimeter leads I had and tested them for continuity, so I'm all set to test. How does tomorrow night sound? (I promised the wife I'd stop playing with my lasers and watch a movie with her tonight...) PM me your Skype deets if you have it. TTYSoon.

CC

Re: Milos Custom Blu-Ray 25mW Laser

you got it. Tomorrow night.

Re: Milos Custom Blu-Ray 25mW Laser

.zzz

Re: Milos Custom Blu-Ray 25mW Laser

All-righty then. :-?

The current measures 46 mA at the battery which is inline with the 42 mA that the pot is set to give to the diode, so we're just scratching our heads until I can do a comparison with a Coherent. I'm going to ask Chimo if that freaky Blu-Ray diode he's got putting out 78mW might put out a similar 26mW if it's throttled back to 42mA. But then he's using the same type of thermopile that's in my meter, so who knows? At least we could see if this reading is reproducible.

The plot thickens... :

CC

Re: Milos Custom Blu-Ray 25mW Laser

you could probably ask the guys at laserglow since they are in the same city as you. maybe you can run over to thier shop and have them read it on thier meter.

Re: Milos Custom Blu-Ray 25mW Laser

Curiously_Coherent said:

I'm going to ask Chimo if that freaky Blu-Ray diode he's got putting out 78mW might put out a similar 26mW if it's throttled back to 42mA.  But then he's using the same type of thermopile that's in my meter, so who knows?  At least we could see if this reading is reproducible.

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I've been asking for the current in his mutant for a while now, but he doesn't know, and can't measure, or change it, because it's all glued together.

I'm guessing he expected the current to be the same as with his first Charge2Go driven BlueRay, and got a surprise, when the second one started burning it's own window..


Oh, and his first one measures at 7-8mW on the same meter, which sounds correct, so it can't be the meter.. Unless of course the first one is broken and only 3-4mW in reality. It did have totally different electrical characteristics, so it is possible..


But it's weird to say the least..

Re: Milos Custom Blu-Ray 25mW Laser

Here's a thought... On the Coherent spec page for the Lasercheck (http://www.coherent.com/Lasers/index.cfm?fuseaction=show.page&id=250&loc=830) it says that it's wavelength sensitivity is from 400-1064nm, which puts the Blu-Ray 405nm wavelength very near it's lower limit. Add to that the fact that in order to read over 10mW, you have to engage the attenuator filter, which would further impair reading at the unit's outer limits, and I'm beginning to think that a Lasercheck's readings for 405nm might be a bit suspect.

If the thermopile heads used in Kenoms and the DIY meters are spectrally flat, (as knimrod asserts and the Coherent specs confirm), then I'd say they are much more capable of capturing all the energy a diode is putting out. We've already seen this in the way the thermopile meters can register the leaking IR of the DX greens and quantify it with use of an IR filter.

I'll call Justin to see if he'll let me come in and test this on their meter. (I'd like to have them look at my Vega-5 anyway). However, I'm starting to believe that Milos' Lasercheck readings of 16mW were actually low due to that unit's limited accuracy at 405nm, and that I'd better be treating this little über-diode with care.

Which makes me one freakin' happy customer, BTW! [smiley=thumbsup.gif]

Cheers, CC

Re: Milos Custom Blu-Ray 25mW Laser

You should be very happy..

I wish i would get at least one of these monsters in the current group buy.. Unfortunatelly, it is possible, that they are not used anymore..


Before now, i thought all of them were supposed to be that bright.. Now it looks like i was just lucky the first time..

If you can call killing it with ESD after only 30 seconds lucky, that is... :'(

Re: Milos Custom Blu-Ray 25mW Laser

I certainly don't know what to say as far as the accuracy of the lasercheck. I wouldn't think that since it's range starts at 400nm that it would be innacurate at that wavelength. certainly far from it. I hope that they will let you come over to thier shop and let you use a meter. I love those guys.

Re: Milos Custom Blu-Ray 25mW Laser

hehe, yeh, I wish I could drop by laserglow so easily too.

Laser check does have limitations and is not something to be excluded. Mine is just about 12 months old mow, and much like CC's new coherent check has been very consistent with its measuring. However, there is that 10mW slide on filter that pisses me off specially when I make 10mW laser. When tested without filter 10mW displays as much as 12-14mW before it beeps. When I put filter on, same laser displays 9-10mW. So maybe its the filter of this laser thats not perfect, but still its only few milliwatts off. I also tend to set it so in any case you get at least milliwatt or two extra just in case.

This is one of main reasons I want to still get your meter Ken, so I can get second opinion on all my lasers I make, as well as learn more about all this.

btw, what 405 diode did Chimo use to get 78mW?

Re: Milos Custom Blu-Ray 25mW Laser

Milos said:

hehe, yeh, I wish I could drop by laserglow so easily too.

btw, what 405 diode did Chimo use to get 78mW?

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That's assuming Justin will be keen on that, he's a hard guy to get a hold of sometimes.

I'm not sure what diode he was using but here's the post he mentions it in first. http://www.laserpointerforums.com/forums/YaBB.pl?num=1200112201/339#339

Cheers, CC

Re: Milos Custom Blu-Ray 25mW Laser

Okay folks, I've just talked to Justin @ Laserglow and he's into doing a bit of testing of the Kenometer vs. the various thermopile units and Lasercheck they have there, specifically at the 405nm wavelength. I'll be meeting with him Tuesday evening, so I hope to have some definitive answers soon. He's also eager to show me the 10x extender, so I'll be posting a hands-on review of that as well.

It should be a very informative evening. I'll keep y'all informed.

Cheers, CC

Re: Milos Custom Blu-Ray 25mW Laser

excellent !!

I'm looking forward to all the info .