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DIY Pre-Calibrated LPM for under $100.00....

rbc1225

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boo. hiss. necro-post. I was expecting you to tell me where I can find my $100 LPM. :yabbmad:
heheheh Well it is now $205.00 but you can get the OPHIR in Jerrys post here off of Ebay for $205.00. I am sure it was $100.00 a few years ago when this thread started, but you know how it is.
 



lasersbee

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It's not necroposting if you add some useful info
to the old thread like where to get some elusive
build parts for the Thread project today..:beer:


Jerry

You can contact us at any time on our Website: J.BAUER Electronics
 

rbc1225

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True Jerry, I agree. There are also these sensors "Ophir OEM Laser Power Meter Sensor for CO2 YAG 60W" and I know the one in the top of this thread is only good for about 5 watts but and the one I have list here is for 60w but I wasn't sure of the wavelength designations so I went ahead and just got the one you recommended in this thread. Would this one have worked as well? The part number is 150C-A-.1-C/ERB

The description says the Absorber is optimized for CO2 (10.6um) and Er:YAG (2.94um) lasers. Other CW or long pulse lasers should be OK as well (non Q-switched lasers).
 
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dmacrae

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I'm always on the prowl for an ophir head. bumping a useful thread like this is a good thing IMO. I wasn't actively searching for it but came across it and left with some good info.
 

lasersbee

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True Jerry, I agree. There are also these sensors "Ophir OEM Laser Power Meter Sensor for CO2 YAG 60W" and I know the one in the top of this thread is only good for about 5 watts but and the one I have list here is for 60w but I wasn't sure of the wavelength designations so I went ahead and just got the one you recommended in this thread. Would this one have worked as well? The part number is 150C-A-.1-C/ERB

The description says the Absorber is optimized for CO2 (10.6um) and Er:YAG (2.94um) lasers. Other CW or long pulse lasers should be OK as well (non Q-switched lasers).
No you could not use that Head directly...
It does not output 1V/1W...
That head outputs 0.1V/W and would require a
stable and precise amplifier stage to bring it up
to 1V/1W....


Jerry

You can contact us at any time through our Website: J.BAUER Electronics
 

Trevor

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No you could not use that Head directly...
It does not output 1V/1W...
That head outputs 0.1V/W and would require a
stable and precise amplifier stage to bring it up
to 1V/1W....


Jerry

You can contact us at any time through our Website: J.BAUER Electronics
Alternatively, you could take note of the calibration of the sensor and calculate actual power by multiplying what the DMM displays.

Trevor
 

rbc1225

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Wow this is a rough forum. I get negative feedback because I revived this thread. That sort of sucks. Oh well nothing I can do about that.

My multimeter also reads millivolts so that wouldn't be a problem. What about the wavelength of the sensor?

Would it be usable in the spectrum we normally use? It indicated the absorber is for CO2 (10.6um) and Er:YAG (2.94um) lasers. Other CW or long pulse lasers should be OK as well (non Q-switched lasers).

That was my concern. I have no problem reading the output if it is reasonably accurate like the one originally recommended at the top of this thread.

It would only be good for higher power lasers though, or so it seams. I mean 5 watts gives me .5 volts instead of a full 5 to deal with on an analog input board. Is that what you mean Jerry. Our ADC if read other than directly would only be using a very low end of an analog input?
 
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lasersbee

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Wow this is a rough forum. I get negative feedback because I revived this thread. That sort of sucks. Oh well nothing I can do about that.

My multimeter also reads millivolts so that wouldn't be a problem. What about the wavelength of the sensor?

Would it be usable in the spectrum we normally use? It indicated the absorber is for CO2 (10.6um) and Er:YAG (2.94um) lasers. Other CW or long pulse lasers should be OK as well (non Q-switched lasers).

That was my concern. I have no problem reading the output if it is reasonably accurate like the one originally recommended at the top of this thread.

It would only be good for higher power lasers though, or so it seams. I mean 5 watts gives me .5 volts instead of a full 5 to deal with on an analog input board. Is that what you mean Jerry. Our ADC if read other than directly would only be using a very low end of an analog input?
First... don't worry about the neg rep... your Rep Powers
under your Avatar will only show once you hit 50 Posts.

Using a DMM that can only read mV would give that head
a resolution of 10mW plus ant DMM errors if the head is
still calibrated.

As I stated above to get a 1mV/1mW output from that head
with a resolution of 1mW you would need to use a stable
an precise amplifier stage.

I'm not sure if those heads are still calibrated in the visible
spectrum like the 20C heads. We've never had on in the
shop.

Alternatively, you could take note of the calibration of the sensor and calculate actual power by multiplying what the DMM displays.
I find that amusing coming from a guy that is so obsessed
with fractional readings...:yh:

Using a calculator would only multiply any values by 10
but the resolution would still be only 10mW. You can easily
do that in your head by moving the decimal point to the
right by one place.


Jerry

You can contact us at any time on our Website: J.BAUER Electronics
 
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Trevor

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I find that amusing coming from a guy that is so obsessed
with fractional readings...:yh:

Using a calculator would only multiply any values by 10
but the resolution would still be only 10mW. You can easily
do that in your head by moving the decimal point to the
right by one place.


Jerry
Assuming it's calibrated to ±3%, the readings are only rated accurate to ±4.5W at the top of the range. Considering we're using 1.0 - 1.5% of that 150W range with lasers the average hobbyist has, you can't expect a lot of precision. Especially with an old surplus sensor. You've got to verify it with a known, calibrated LPM before you can even remotely trust it.

These factors taken into account, 10mW is more than enough resolution.

I thought you would know that, but I'm glad I could help you out. :yh:

Trevor
 
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Bob_Boyce

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Back when Kenom was working with those Ophir heads, I bought a large batch of heads from the supplier, intended to be used for his laser power meters. I spent over $5000 of my own money on that Ophir head buy, and more $ on other parts for him. I sent the majority of those heads to Ken, but did not get back even 10% of my investment. When the heads were going out fast, yet money was not coming back, I decided to stop sending them and cut my losses. I kept over a dozen of those Ophir heads, and I still have them. But even if I were to sell what I have left for $200 each, I could not recover my initial investment. It sure made me wary about getting financially involved with anyone else on this forum.

Bob
 

SpyderFire

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@ Deranged Units - Do you mean alot of other members lost $ to Kenom or to other projects? .

"."


@Bob , how much would you sell me a single Ophir head thermopile?
 
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lasersbee

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Back when Kenom was working with those Ophir heads, I bought a large batch of heads from the supplier, intended to be used for his laser power meters. I spent over $5000 of my own money on that Ophir head buy, and more $ on other parts for him. I sent the majority of those heads to Ken, but did not get back even 10% of my investment. When the heads were going out fast, yet money was not coming back, I decided to stop sending them and cut my losses. I kept over a dozen of those Ophir heads, and I still have them. But even if I were to sell what I have left for $200 each, I could not recover my initial investment. It sure made me wary about getting financially involved with anyone else on this forum.

Bob
Hey Bob....

I've heard that from quite a few members here that ended up with
a bad taste in their mouths after taking a bite out of the apple named
Kenom.

Luckily I didn't buy a huge supply of those heads even though I was
accused of stomping out Kenom's LPM business for buying them all
out...
The truth always has a way of coming out in the end...

At least I know where I can get some when/if I need any...;)
Nice to see you back...:beer:


Jerry

You can contact us at any time on our Website: J.BAUER Electronics
 
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@SpeediernFyre:
Learn to write name/nickname right, then il tell you!



As for others: Im not going back on the subject, we all know the story. Lets move on!
 
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rbc1225

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Back when Kenom was working with those Ophir heads, I bought a large batch of heads from the supplier, intended to be used for his laser power meters. I spent over $5000 of my own money on that Ophir head buy, and more $ on other parts for him. I sent the majority of those heads to Ken, but did not get back even 10% of my investment. When the heads were going out fast, yet money was not coming back, I decided to stop sending them and cut my losses. I kept over a dozen of those Ophir heads, and I still have them. But even if I were to sell what I have left for $200 each, I could not recover my initial investment. It sure made me wary about getting financially involved with anyone else on this forum.

Bob
We have all lost money to someone on projects at one time or another, that is if you are old enough to have actually done or tried to do something in life. Probably the best place to sell what you have is BST thread and keep it bumped. I would have much rather purchased from you or someone on this forum than someone off Ebay, but didn't know any different at the time.
 

Bob_Boyce

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Very Nice to hear from you again Bob, sorry for your loss. There many others member Who lost $ too.
Thank you, I'm glad to be back. Though I doubt I'll get as involved in the forum here that I had been back then.

@Bob , how much would you sell me a single Ophir head thermopile?
I'm not really interested in selling them off now, which is why I've not offered them for sale. I lost too much money on that whole ordeal to sell them for what I would want to sell them for. I don't want the members here to pay through the nose to buy them for what I would have to sell them for just to break even. I would probably have to sell them off commercially to do that.

Hey Bob....

I've heard that from quite a few members here that ended up with
a bad taste in their mouths after taking a bite out of the apple named
Kenom.

Luckily I didn't buy a huge supply of those heads even though I was
accused of stomping out Kenom's LPM business for buying them all
out...
The truth always has a way of coming out in the end...

At least I know where I can get some when/if I need any...;)
Nice to see you back...:beer:


Jerry

You can contact us at any time on our Website: J.BAUER Electronics
Thank you Jerry

Yes, I was disgusted with the whole mess of the microcontroller based LPM that was being offered to the members here. Many times I had pointed out that the design being offered was heavilly flawed, yet I was ignored. They continued to take money for a product that was not properly designed/built. Hardware issues were being hidden by fudging things in software. I wanted no part of it myself. By that time, I had already shipped off over 3/4 of the 102 sensor heads I had bought. I still have the list of serial numbers of all sensor heads bought and I kept a log of the serial numbers of those shipped.

I had already designed an aluminum enclosure that properly heatsinked the sensor head and built a prototype for myself. I worked with a machinist to crank out 20 more of those enclosures. I had bought enough isolated power supplies, DC/DC converters, displays, range switches, and high quality potentiometers for the zero control. I shipped all of them off. I don't even know what happened to those enclosures, I would love to have them now.

We have all lost money to someone on projects at one time or another, that is if you are old enough to have actually done or tried to do something in life. Probably the best place to sell what you have is BST thread and keep it bumped. I would have much rather purchased from you or someone on this forum than someone off Ebay, but didn't know any different at the time.
I agree. I have lost a bit of money here and there over the years on various projects, but not to the scale of this on a single project. The worst part about this whole mess, I was just trying to help someone and I was not expecting to turn any profit. I expected to be reimbursed for my costs on a unit by unit basis as they were sold off. Of course, that did not happen.

As I mentioned above, I don't want to offer these to forum members. I would have to bump the per unit cost way up to TRY to recover at least a decent portion of my investment and I don't want to make members here pay for my error in judgement.

Bob
 




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