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Tornado Laser Power Meter From The Laser Pointer Store

skijohn

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Here we go again... :cautious:
 

Encap

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I really don't understand what is to be gained by getting one of these cheap LPMs. One can take it apart and see what it does or doesn't have in it. But, to what end? To me it is just a cheap meter not worth the $$$ or effort to find out.
Exactly.
I don't understand why anyone would waste time on investigating either.

It is the same as the "pocket" LPM minus the battery and charger.
Is just another toy quality entertainment low end/low quality POS product from a money grubbing little international outlaw reseller hiding in China to avoid getting nabbed for his illegal laser smuggling, warehousing, and sales activities in several Countries who would be selling ping pong balls if he was not doing otherwise. LOL

All those LPMs actually demonstrate is that the Chinese mentality/attitude stereotype that " Money is God and God is Money" is sometimes very true.
 
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Benm

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I really don't understand what is to be gained by getting one of these cheap LPMs. One can take it apart and see what it does or doesn't have in it. But, to what end? To me it is just a cheap meter not worth the $$$ or effort to find out.
But if it was actually a very good meter, build cheaply but smartly? What if it even was accurate, for only $55.

If it was actually good it'd be a fantastic deal and everyone should buy one. I seriously doubt it is due to the odd measurements obtained at lower power levels, but those are just single measurements, not tests over numerous units.

As Jerry, Bob and I tried to explain the ADC and display part of this unit would not be very expensive to construct using fairly jelly bean components. You can basically get a $1 or $2 uC that has adequate ADC's and can drive the display etc, basically the chip that does everything. Maybe not quite the anonymous-8-pin-chip if you want to drive the display, but there are plenty of sub $2 processors that have a few more inputs/outputs and enough sram, program memory and eeprom storage built in to do it all.

The question is, to me, mostly what the sensor is and how that works. $55 is still a shitload of money for all parts but the sensor, if it were just a volt meter in that form factor it would probably cost under $5 shipped ;)
 

Encap

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The question is, to me, mostly what the sensor is and how that works. $55 is still a shitload of money for all parts but the sensor, if it were just a volt meter in that form factor it would probably cost under $5 shipped ;)
Benm: This from Laserbees look see at the first "pocket " units. No reason to think is is any different today other than perhaps a slightly different black coating

"Sensor

Looking closely at the sensor I found it to be a TEC
that measures 10mm X 6mm X 1.5mm with ~50 P/N
junctions outputting ~159mV/W.
The 100% response time was ~21 seconds.

The actual Sensor Plate is a thin copper sheet that
is larger than the Tec and measures ~12.6mm X 11.6mm.
That plate is Paint Brush coated with some type of
black semi-shiny paint.

If a Laser is shone on the Plate over the TEC the readings
will be fine since the TEC will bleed off the heat produced.
If a Laser is shone on the Plate not over the TEC the
heat will build up quickly and reduce the Max power of
the sensor.

It seems that the copper plate is attached to the TEC
by the same white silicone that is liberally used inside the
enclosure. The TEC is mounted to the copper heatsink
again with white silicone.
The finned copper heatsink measures 26.9mm X 16.2mm
X 11.2mm and is also attached to the alluminium enclosure
by again... white silicone.
I can't see this small Heatsink capable of dissipating 15W
even if the Coating could handle it."
See Jerry's review here: https://laserpointerforums.com/threads/review-of-the-new-15w-lpm-from-lps.101715/
and Lasersbee's schematic of the pocket unit at end of OP
 

BobDiaz

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I really don't understand what is to be gained by getting one of these cheap LPMs. One can take it apart and see what it does or doesn't have in it. But, to what end? To me it is just a cheap meter not worth the $$$ or effort to find out.
I know this seems pointless, but sometimes it's just fun to explore things to see how the operate. I also love to look inside things to see how they tick. It really doesn’t matter if it’s the greatest meter ever (not likely) OR total junk (likely), it’s just fun to explore and see how accurate it is or isn’t.
 

paul1598419

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Then you should pick up a professional meter on eBay and delve into that thing. You will learn much more from that than you will from this heap of junk.
 

Benm

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It's the sensor that's likely the problem indeed, and if it's the same as the one from the previous model there would be little point in doing a teardown. If the coating is different, or perhaps even the whole thermal design from the absorbing surface through the TEC and then onto the case was overhauled, performance could be better.

The laserbee and hyperion meters are also TEC based, though built pretty well and having a good solution for translating the measurement to a realistic power level, which is a big step up from just a potentiometer and mV meter connected after that.

I guess in some cases the difference is just in the software, like between the laserbee A10 and A10 RTA: those are identical where it comes to hardware afaik, but the RTA model does some calculations to predict what the steady state would be before actually reaching it.

If absolute accuracy is important to you it also helps that these units are calibrated with the calibration data stored in the uC eeprom instead of by some pot that could be moved due shock, vibration etc during shipping.
 




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