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FrozenGate by Avery

DIY Laser Power Meter

The display is not the one that I will use in the end...
I just used it to be able to get a cutout, and to make sure everything would fit...

It gives an idea what my final meter will look like.

The box is the Radioshack box in your parts list...Radioshack part number 270-1803.

The meter I have there in the picture is one of these:

Ebay item number: 280196156658



I have ordered 2 of these: Ebay # 160201607248 to use in the final version.
Since this meter is slightly smaller than the one I cut out today..I will need to make another lid..


I will be able to use this lid to transfer the hole locations
Since everything fit with this display...there should be no problem fitting the permanent display.

Speaking of that...Knimrod...that meter 160201607248 that you list...what are the hatch cutout dimensions???
The only dims on the auction gives overall dimensions of 72mm(W) x 36mm(H) x 25mm(D)

I'm very pleased with the way it came out

Larry
 





LarryQ said:
The display is not the one that I will use in the end...
I just used it to be able to get a cutout, and to make sure everything would fit...

It gives an idea what my final meter will look like.

The box is the Radioshack box in your parts list...Radioshack part number 270-1803.

The meter I have there in the picture is one of these:

Ebay item number: 280196156658



I have ordered 2 of these: Ebay # 160201607248 to use in the final version.
Since this meter is slightly smaller than the one I cut out today..I will need to make another lid..


I will be able to use this lid to transfer the hole locations
Since everything fit with this display...there should be no problem fitting the permanent display.

Speaking of that...Knimrod...that meter 160201607248 that you list...what are the hatch cutout dimensions???
The only dims on the auction gives overall dimensions of 72mm(W) x 36mm(H) x 25mm(D)

I'm very pleased with the way it came out

Larry
Click to expand...

The cut-out dimensions listed in the installation manual are 68.5mm x 34.2mm.

I can't attach the pdf of the manual here but if you PM me your email address, I can email it to you.
 
In case anybody's curious, here's what the inside of the sensor looks like. I figured I have nothing to lose by opening it. There are 30 thermocouple pairs on the back side of the ceramic disc (the other side has the grey circle you normally see).
Measuring the resistance across each pair, most of them are around 4.5 Ohms, but a few are as high as 7. One of them is an open circuit! I figure I'll try bridging across this pair, which would reduce the output voltage by 1/30th or 3.3%.
There's a 10K pot inside the case where it was calibrated, but rather than messing with that I figure I'll just reduce the resistance of the gain pot on the amp by 3.3%.
Worth a try anyway.
 

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  • Thermopile1.jpg
    Thermopile1.jpg
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;D Initial tests look positive! I'm seeing reactions from the lasers I have on hand, in the general ballpark of what I'd expect now. Cool.
Now to button it all back up and put it in a case. (Just going for external meter output for now.)
I'll be interested to see if people are getting the BluRay output they expected - Mine seems lower than I expected based on the posted power curves, but then mine has a blown red - that could have affected the violet I suppose.
 
Zarniwoop said:
In case anybody's curious, here's what the inside of the sensor looks like.  I figured I have nothing to lose by opening it.  There are 30 thermocouple pairs on the back side of the ceramic disc (the other side has the grey circle you normally see).
Measuring the resistance across each pair, most of them are around 4.5 Ohms, but a few are as high as 7.  One of them is an open circuit!  I figure I'll try bridging across this pair, which would reduce the output voltage by 1/30th or 3.3%.
There's a 10K pot inside the case where it was calibrated, but rather than messing with that I figure I'll just reduce the resistance of the gain pot on the amp by 3.3%.
Worth a try anyway.
Click to expand...

Interesting.. Sorry to hear you have a dud but it looks like maybe you can fix it. Regardless, thanks for sharing the information. As I suspected, it looks pretty typical of the Coherent thermopile sensors I'm aware of.
 
Zarniwoop said:
;D  Initial tests look positive!  I'm seeing reactions from the lasers I have on hand, in the general ballpark of what I'd expect now.  Cool.
Now to button it all back up and put it in a case.  (Just going for external meter output for now.)
I'll be interested to see if people are getting the BluRay output they expected - Mine seems lower than I expected based on the posted power curves, but then mine has a blown red - that could have affected the violet I suppose.
Click to expand...
[smiley=thumbsup.gif] [smiley=beer.gif]
 
Why are people ordering 20 or 200V panel meters rather than 2V, which would measure up to 2 Watts of laser output? I'd want to keep as much precision as possible, and I doubt that some of these are auto-ranging.
 
Zarniwoop said:
Why are people ordering 20 or 200V panel meters rather than 2V, which would measure up to 2 Watts of laser output?  I'd want to keep as much precision as possible, and I doubt that some of these are auto-ranging.
Click to expand...

The 200V panel meter I ordered from Ebay can be configured for 2V with a simple change of a DIP switch.    That will give 1mW resolution from 0 - 1.999 Watts.
 
I saw that one - but some of the other ones have a fixed range. It'd be a shame if somebody ends up with 10mw precision. Just tossing that out there for people to be aware of.
 
it is very easy to make. The tutorial is very thorough. If you don't want to make one yourself you can look in the bu/sell/trades section where I've got not this exact meter but a meter utilizing the board in a nice enclosure all setup for sale. for $150 it's certainly cheaper to make it yourself.
 
knimrod said:
(01/30/08)
Second Group Buy:
  • turtlecannon: 1
  • Buffo: 2
  • Knimrod: 2
  • desslok: 1
  • Remaining: 3
Click to expand...

I'll take 1 please, just let me know where on paypal i'm sending payment. thanks!
 
RoSSco, sorry for taking so long to reply - work was crazy this week and I have to head out of town again on Sunday for the week. Can you PM me you paypal info and I will send payment off before I leave? Thanks,

Paul
 
I received my board today, it looks great! Warming up the soldering iron now! ;D
Thanks.
 
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