Laser pointer discussion. Read/write reviews of laser pointers and laser pointer companies. Learn about all types of laser pointers and lasers





Welcome to Laser Pointer Forums! If you are looking for a laser pointer or want to compare different laser pointer companies, you may want to check out the LPF Laser Pointer Company Database. The link will open in a new window for your convenience.








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes
Laser Technology Laser Pointer Parts Lasers by Wavelength
Top 10 Laser Pointer Companies Laser Pointer Company Database Visible Beam Laser Pointers


One laser store meets all your needs

























Go Back   Laser Pointer Forums - Discuss Laser Pointers > Lasers > Buy, Sell, & Trade



LPF List of Laser Pointer Companies (link opens new window)



Reply
 
LinkBack Thread Tools Display Modes
Old 04-26-2015, 06:01 AM #17
Jstr's Avatar
Class 2 Laser
 
Join Date: Feb 2014
Location: Houston, Texas
Posts: 347
Rep Power: 447
Jstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond repute
Jstr Jstr is offline
Class 2 Laser
Jstr's Avatar
 
Join Date: Feb 2014
Location: Houston, Texas
Posts: 347
Rep Power: 447
Jstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond repute
Default Re: USB Portable Powerful 12W Custom LPM

Looks great, put me down for one please


__________________
405nm Cypreus IIb (1W)
405nm Polished Minisaber (<1W)
450nm Ehgemus (2.7W)
450nm Sanwu Silver Series (3W)
450nm Cypreus pen (1W)
450nm Gold leadlight pen (1.5W)
450nm Cypreus pen (1.6W broken)
520nm S4 (200mw)
532nm Ehgemus pointer (100mw)
632.8nm HeNe (.5mw)
638nm Ehgemus (1W)
650nm Sanwu Pocket Pen (200mw)
15W 10.6um CO2 tube
Jstr is offline   Reply With Quote







LPF List of Laser Pointer Companies (link opens new window)







Old 04-29-2015, 04:21 PM #18
Podo's Avatar
Class 2M Laser
 
Join Date: Nov 2013
Location: Hong Kong
Posts: 524
Rep Power: 4468
Podo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond repute
Podo Podo is online now
Class 2M Laser
Podo's Avatar
 
Join Date: Nov 2013
Location: Hong Kong
Posts: 524
Rep Power: 4468
Podo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond repute
Default Re: USB Portable Powerful 12W Custom LPM

It's a really great LPM if you don't need data logging and want a quick and precise readings for your handheld lasers! Feel no hesitate pm me at anytime!
Podo is online now   Reply With Quote
Old 04-29-2015, 05:50 PM #19
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default

Quote:
Originally Posted by Podo View Post
It's a really great LPM if you don't need data logging and want a quick and precise readings for your handheld lasers! Feel no hesitate pm me at anytime!
It's USB.... how does it not have data logging? Isn't that just a matter of the software running on the PC, not the LPM hardware?

Can you show a photo of the software?
rhd is offline   Reply With Quote
Old 04-30-2015, 08:22 AM #20
Podo's Avatar
Class 2M Laser
 
Join Date: Nov 2013
Location: Hong Kong
Posts: 524
Rep Power: 4468
Podo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond repute
Podo Podo is online now
Class 2M Laser
Podo's Avatar
 
Join Date: Nov 2013
Location: Hong Kong
Posts: 524
Rep Power: 4468
Podo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond repute
Default Re: USB Portable Powerful 12W Custom LPM

The usb plug is a more convenient way as a power connection to the led display and the display is not configured with RS232 output right now though the point is the sensor don't require any power. One can connect it to any display devices which have more functions.

Last edited by Podo; 05-01-2015 at 01:45 AM.
Podo is online now   Reply With Quote
Old 04-30-2015, 10:32 PM #21
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default

Quote:
Originally Posted by Podo View Post
The usb plug is a more convenient way as a power connection to the led display and the display is not configured with RS232 output right now though this point is the sensor don't require any power. One can connect it to any display devices which have more functions.
Wait, so this doesn't even interface with a PC? It's just the TEC, a heatsink, and an LED voltmeter, for $150?
rhd is offline   Reply With Quote
Old 05-01-2015, 01:49 AM #22
Podo's Avatar
Class 2M Laser
 
Join Date: Nov 2013
Location: Hong Kong
Posts: 524
Rep Power: 4468
Podo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond repute
Podo Podo is online now
Class 2M Laser
Podo's Avatar
 
Join Date: Nov 2013
Location: Hong Kong
Posts: 524
Rep Power: 4468
Podo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond repute
Default Re: USB Portable Powerful 12W Custom LPM

Really? Even before I lowered my first suggested price, that wasn't high as $150 neither.
Podo is online now   Reply With Quote
Old 05-01-2015, 07:11 AM #23
Jstr's Avatar
Class 2 Laser
 
Join Date: Feb 2014
Location: Houston, Texas
Posts: 347
Rep Power: 447
Jstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond repute
Jstr Jstr is offline
Class 2 Laser
Jstr's Avatar
 
Join Date: Feb 2014
Location: Houston, Texas
Posts: 347
Rep Power: 447
Jstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond repute
Default Re: USB Portable Powerful 12W Custom LPM "Persale Price"

Quote:
Originally Posted by rhd View Post
Wait, so this doesn't even interface with a PC? It's just the TEC, a heatsink, and an LED voltmeter, for $150?
try $85. A great deal for a 10 watt LPM with very good response time for being thermal, no matter how you look at it.
__________________
405nm Cypreus IIb (1W)
405nm Polished Minisaber (<1W)
450nm Ehgemus (2.7W)
450nm Sanwu Silver Series (3W)
450nm Cypreus pen (1W)
450nm Gold leadlight pen (1.5W)
450nm Cypreus pen (1.6W broken)
520nm S4 (200mw)
532nm Ehgemus pointer (100mw)
632.8nm HeNe (.5mw)
638nm Ehgemus (1W)
650nm Sanwu Pocket Pen (200mw)
15W 10.6um CO2 tube
Jstr is offline   Reply With Quote
Old 05-01-2015, 01:46 PM #24
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default

Quote:
Originally Posted by Jstr View Post
try $85. A great deal for a 10 watt LPM with very good response time for being thermal, no matter how you look at it.
$85 is a lot better than the original $150. I'm glad the price criticism of that original selling price was taken on board.

While I still struggle to understand what you're paying for here if the USB is fake, and this doesn't actually contain any "brains" to interface with a PC, I suppose there are worse ways to spend $85.

It still seems to me that this is just the $50 DIY LPM that has been kicking around for a while on LPF (http://laserpointerforums.com/f42/diy-thermal-lpm-under-50-a-51129.html). And while I have a bit more faith in the design of the BlueFan Basic (http://store.bluefan.nl/index.php?location=power_meters), particularly the larger heatsink, admittedly, at 70 euros, it's not that much cheaper than the above, and I'm not sure if it's still available.

I still can't get past this 12W claim though. How is that tiny heatsink dissipating sufficient heat that the differential (which is all it can measure) doesn't shrink dramatically and hugely impact readings? I mean, just hop on Digikey and check out the specs of heatsinks of that size and style. You're not going to find one that can handle 12W without a significant rise in temperature. Good design and smart electronics only take you so far, it's pretty hard to get around the reality of heat...
rhd is offline   Reply With Quote
Old 05-01-2015, 05:06 PM #25
Podo's Avatar
Class 2M Laser
 
Join Date: Nov 2013
Location: Hong Kong
Posts: 524
Rep Power: 4468
Podo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond repute
Podo Podo is online now
Class 2M Laser
Podo's Avatar
 
Join Date: Nov 2013
Location: Hong Kong
Posts: 524
Rep Power: 4468
Podo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond reputePodo has a reputation beyond repute
Default Re: USB Portable Powerful 12W Custom LPM "Persale Price"

The tec is only about 1.6mm thick under covered a graphite coated copper sheet with 15*15 active surface. A normal tec is about 3mm and if you still think this is a $50 lpm that people are doing a long time ago.

At least that explained all your skeptical theories. It can handle the heat because it is a total different tec being used with 50*50*40 heatsink together, I will try to not dig deep down on this as I am not the creator.

Most of the cost is from the sensor itself but not a an interface or programme for computer output as it can be done quite easily and cheap.

And if you still feeling struggle to believe what he accomplished here is not a replica from old tutorials that some members posted years ago, how about a question for you?

Can you explain how to achevie 1mV=10mW sensor without any power feeding?

Last edited by Podo; 05-05-2015 at 03:02 PM.
Podo is online now   Reply With Quote
Old 05-01-2015, 05:54 PM #26
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default

Quote:
Originally Posted by Podo View Post
And if you still feeling struggle to believe what he accomplished here is not a replica from old tutorials that some members posted years ago, how about a question for you?

Can you explain how to achevie 1mV=10mW sensor without any power feeding?
Don't go ad hominem just to avoid the (inconvenient) skepticism about the ability of that tiny heatsink to absorb 12W without a substantial rise in case temperature. In any event, I'm not taking issue with the fact that your LPM needs a power feed, I believe most do. I'm taking issue with the unit's inexplicable ability to avoid the basic thermal dissipation specs of its heatsink, and now, with your use of logically fallacious discussion strategies in responding to criticism.
rhd is offline   Reply With Quote
Old 05-04-2015, 06:40 AM #27
Jstr's Avatar
Class 2 Laser
 
Join Date: Feb 2014
Location: Houston, Texas
Posts: 347
Rep Power: 447
Jstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond repute
Jstr Jstr is offline
Class 2 Laser
Jstr's Avatar
 
Join Date: Feb 2014
Location: Houston, Texas
Posts: 347
Rep Power: 447
Jstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond repute
Default Re: USB Portable Powerful 12W Custom LPM "Persale Price"

Quote:
Originally Posted by rhd View Post
Don't go ad hominem just to avoid the (inconvenient) skepticism about the ability of that tiny heatsink to absorb 12W without a substantial rise in case temperature. In any event, I'm not taking issue with the fact that your LPM needs a power feed, I believe most do. I'm taking issue with the unit's inexplicable ability to avoid the basic thermal dissipation specs of its heatsink, and now, with your use of logically fallacious discussion strategies in responding to criticism.
I can see your concern for heating, and I was thinking the same thing, so I did some calculations:

So let's say the LPM absorbs 180 joules of heat from a 12 watt laser over 15 seconds response time. The specific heat of aluminum is .9 J/gram Kelvin and I'd estimate that heatsink to be about 100 grams, so we have 180J=(.9)(100)(delta temp). The rise in temperature should be 2 degrees Celsius and that does not account for dissipation from the heatsink over 15 seconds or the heat that goes into electrical energy. Not to mention that who is going to have a 12 watt laser?? (And where can I buy one?! ) I could be wrong, but I bet <2 degrees can't skew the reading too terribly.

Maybe we can get a better heatsink, but I'm not all that concerned because my most powerful laser is around 3 watts
__________________
405nm Cypreus IIb (1W)
405nm Polished Minisaber (<1W)
450nm Ehgemus (2.7W)
450nm Sanwu Silver Series (3W)
450nm Cypreus pen (1W)
450nm Gold leadlight pen (1.5W)
450nm Cypreus pen (1.6W broken)
520nm S4 (200mw)
532nm Ehgemus pointer (100mw)
632.8nm HeNe (.5mw)
638nm Ehgemus (1W)
650nm Sanwu Pocket Pen (200mw)
15W 10.6um CO2 tube
Jstr is offline   Reply With Quote
Old 05-04-2015, 01:22 PM #28
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default

Quote:
Originally Posted by Jstr View Post
I can see your concern for heating, and I was thinking the same thing, so I did some calculations:

So let's say the LPM absorbs 180 joules of heat from a 12 watt laser over 15 seconds response time. The specific heat of aluminum is .9 J/gram Kelvin and I'd estimate that heatsink to be about 100 grams, so we have 180J=(.9)(100)(delta temp). The rise in temperature should be 2 degrees Celsius and that does not account for dissipation from the heatsink over 15 seconds or the heat that goes into electrical energy. Not to mention that who is going to have a 12 watt laser?? (And where can I buy one?! ) I could be wrong, but I bet <2 degrees can't skew the reading too terribly.

Maybe we can get a better heatsink, but I'm not all that concerned because my most powerful laser is around 3 watts
100g is a very unrealistic weight for that heatsink.

I don't know if your calcs are right or not, but I get a very different impression of the temperature rise from looking at a datasheet:
http://www.digikey.ca/product-detail...38E-ND/2342473

Even based on your calcs, assuming the formula makes sense, but stipulating a more realistic 30g weight for that heatsink and a 60 second LPM run (which is a fairly standard run, if not a bit short, for someone trying to test a laser).

720=0.9x30(rise)
Rise = 27 degrees

If that's the correct formula to be using, that's a dramatic rise. How would that not throw off the readings ?!? That's only 60 seconds. What if you're trying to test stability over 2 minutes?

This 12W business is nonsense. If your argument is "fine, but who has a 12W laser?", then that's just more fallacious reasoning. That's like saying, "my car can go 1,600 miles per hour" and then when challenged on the spec, responding "well, there aren't any roads nearby that will let me actually drive that fast"

Last edited by rhd; 05-04-2015 at 01:51 PM.
rhd is offline   Reply With Quote
Old 05-04-2015, 11:10 PM #29
Class 3R Laser
 
Join Date: Apr 2014
Location: NJ
Posts: 1,296
Rep Power: 174
Teej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond repute
Teej Teej is offline
Class 3R Laser
 
Join Date: Apr 2014
Location: NJ
Posts: 1,296
Rep Power: 174
Teej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond reputeTeej has a reputation beyond repute
Talking Re: USB Portable Powerful 12W Custom LPM "Persale Price"

Quote:
Originally Posted by rhd View Post
100g is a very unrealistic weight for that heatsink.

I don't know if your calcs are right or not, but I get a very different impression of the temperature rise from looking at a datasheet:
EA-T220-38E Ohmite | EA-T220-38E-ND | DigiKey

Even based on your calcs, assuming the formula makes sense, but stipulating a more realistic 30g weight for that heatsink and a 60 second LPM run (which is a fairly standard run, if not a bit short, for someone trying to test a laser).

720=0.9x30(rise)
Rise = 27 degrees

If that's the correct formula to be using, that's a dramatic rise. How would that not throw off the readings ?!? That's only 60 seconds. What if you're trying to test stability over 2 minutes?

This 12W business is nonsense. If your argument is "fine, but who has a 12W laser?", then that's just more fallacious reasoning. That's like saying, "my car can go 1,600 miles per hour" and then when challenged on the spec, responding "well, there aren't any roads nearby that will let me actually drive that fast"
It could also be more like saying my car's speedometer goes to 1,600 mph....but the car can only go 120 mph, etc.





I get the impression that, via a third party, plenty is lost in the translation so to speak between the actual designer, and this forum.

Maybe the designer could weigh in on the technical aspects?
Teej is offline   Reply With Quote
Old 05-05-2015, 12:07 AM #30
Jstr's Avatar
Class 2 Laser
 
Join Date: Feb 2014
Location: Houston, Texas
Posts: 347
Rep Power: 447
Jstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond repute
Jstr Jstr is offline
Class 2 Laser
Jstr's Avatar
 
Join Date: Feb 2014
Location: Houston, Texas
Posts: 347
Rep Power: 447
Jstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond repute
Default Re: USB Portable Powerful 12W Custom LPM "Persale Price"

I'm not arguing with you, really just trying to discern the facts, so please don't get offended or attack me.

Quote:
Originally Posted by rhd View Post
100g is a very unrealistic weight for that heatsink.

I don't know if your calcs are right or not, but I get a very different impression of the temperature rise from looking at a datasheet:
EA-T220-38E Ohmite | EA-T220-38E-ND | DigiKey

Even based on your calcs, assuming the formula makes sense, but stipulating a more realistic 30g weight for that heatsink and a 60 second LPM run (which is a fairly standard run, if not a bit short, for someone trying to test a laser).

720=0.9x30(rise)
Rise = 27 degrees

If that's the correct formula to be using, that's a dramatic rise. How would that not throw off the readings ?!? That's only 60 seconds. What if you're trying to test stability over 2 minutes?
Podo has told me it is actually an 80 gram heatsink. My bad.

To be clear, the following is only an (over) estimate.

The reason I used only 15 seconds is that it is before the LPM reading levels out, there is less heat dissipation from the heatsink (even that gives an overestimate for temperature). That gives 2.5 degrees for a 12 watt laser (or 10 degrees for 60 seconds, but the huge error on that makes that value meaningless).

As heat builds up in the heatsink, the rate of dissipation also increases.

Also, the above estimate does not factor in the heat that is converted into electrical energy, which is typically 5-8% (Thermoelectric generator - Wikipedia, the free encyclopedia), but can be up to 20%
(Thermoelectric materials - Wikipedia, the free encyclopedia).

The whole idea behind these types of LPM's is that there is a temperature difference between the two faces of the peltier chip. As long as there is a maximum temperature (determined not by size, but by surface area of the heatsink) and an equilibrium below a reasonable point, I believe the output voltage and current can be suitable for accurate LPM readings. As long as the specs are such to allow a linear relationship between laser power (input heat) and output voltage (in this case 1mV=10mW), the sensor can be calibrated for accurate and useful readings.

That's why the quintessential nature of a thermal LPM lies in calibration. That's why as long as this is calibrated with a reliable LPM, which it is, it should and does work.

What matters with any electronics heatsink is not the size, but the surface area. The surface area determines the rate of dissipation and how quickly the heatsink reaches an equilibrium temperature, which is what matters. That is the temperature you should worry about, but it's not going to be close to 27 or even 10 degrees.

For what it's worth, my radiant x4's heatsink doesn't get discernibly warmer even after 3 minutes at 3 watts.

Quote:
Originally Posted by rhd View Post
This 12W business is nonsense. If your argument is "fine, but who has a 12W laser?", then that's just more fallacious reasoning. That's like saying, "my car can go 1,600 miles per hour" and then when challenged on the spec, responding "well, there aren't any roads nearby that will let me actually drive that fast"
And that's not ad hominem?

Also, Podo clearly tested it (with multiple lasers), so it's not the same at all.
__________________
405nm Cypreus IIb (1W)
405nm Polished Minisaber (<1W)
450nm Ehgemus (2.7W)
450nm Sanwu Silver Series (3W)
450nm Cypreus pen (1W)
450nm Gold leadlight pen (1.5W)
450nm Cypreus pen (1.6W broken)
520nm S4 (200mw)
532nm Ehgemus pointer (100mw)
632.8nm HeNe (.5mw)
638nm Ehgemus (1W)
650nm Sanwu Pocket Pen (200mw)
15W 10.6um CO2 tube
Jstr is offline   Reply With Quote
Old 05-05-2015, 01:04 AM #31
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default

Quote:
Originally Posted by Jstr View Post
And that's not ad hominem?

Also, Podo clearly tested it (with multiple lasers), so it's not the same at all.
Nope. It's valid analogy. IE, analogizing the flawed reasoning in a manner that retains the underlying logical fallacy (responding to a challenged specification by highlighting the its upper end figure isn't practical anyway).

The test he needs to do is to take a 60 second measurement, and then at second 61, move the beam to an Ophir sensor for an immediate reading, and compare.
rhd is offline   Reply With Quote
Old 05-05-2015, 02:15 AM #32
Jstr's Avatar
Class 2 Laser
 
Join Date: Feb 2014
Location: Houston, Texas
Posts: 347
Rep Power: 447
Jstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond repute
Jstr Jstr is offline
Class 2 Laser
Jstr's Avatar
 
Join Date: Feb 2014
Location: Houston, Texas
Posts: 347
Rep Power: 447
Jstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond reputeJstr has a reputation beyond repute
Default Re: USB Portable Powerful 12W Custom LPM "Persale Price"

Quote:
Originally Posted by rhd View Post
Nope. It's valid analogy. IE, analogizing the flawed reasoning in a manner that retains the underlying logical fallacy (responding to a challenged specification by highlighting the its upper end figure isn't practical anyway).

The test he needs to do is to take a 60 second measurement, and then at second 61, move the beam to an Ophir sensor for an immediate reading, and compare.
Logically I agree with you, but it's not at all the same realistically because 1,600 mph is physically impossible for a car on land and 12 Watts is nothing for industrial LPM's.

The analogy is hyperbolic and insulting to both Podo and the developer of this LPM. Essentially saying "you're full of bs."

I realize I should clarify what I meant by my original statement was that I wouldn't use it for a 12 watt laser. I was in no way making the argument that "it doesn't matter what he claims because it's not practical" because a.) While it may not be practical for me, it is plenty practical to measure 12 watts, otherwise why would any respectable LPM manufacturer carry them? and b.) I wasn't arguing at all... So all this is off topic.

And I would also like to see that test.

I'm not convinced of 12 watts either. So definitely more testing videos would be nice.
__________________
405nm Cypreus IIb (1W)
405nm Polished Minisaber (<1W)
450nm Ehgemus (2.7W)
450nm Sanwu Silver Series (3W)
450nm Cypreus pen (1W)
450nm Gold leadlight pen (1.5W)
450nm Cypreus pen (1.6W broken)
520nm S4 (200mw)
532nm Ehgemus pointer (100mw)
632.8nm HeNe (.5mw)
638nm Ehgemus (1W)
650nm Sanwu Pocket Pen (200mw)
15W 10.6um CO2 tube

Last edited by Jstr; 05-05-2015 at 02:34 AM.
Jstr is offline   Reply With Quote
Reply





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On











Loading








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes






Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 12:52 AM.


Powered by: vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC