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Looking for cheapest functional LPM (laser power meter). Will this one work?

L

lasermore

Member
Joined
Mar 2, 2019
Messages
32
Points
8





Do you know that you also need a head to go with that ?

The next LPM I buy will be the sanwu for 250.00 as I saw it tested against a laserbee and was told the head is solid as in it has a good quality coating.
 
lasermore said:
Does this $75 one from laserpointerstore.com work:
laserpointerstore.com

Laser Pointer Store Pocket Laser Power Meter No.1 Online Laser Store

This is the latest portable laser power meter. It's mini, fashion and accurate.
laserpointerstore.com laserpointerstore.com
Click to expand...
NO NO it's toy grade gimmick meter that's not very accurate and probably worth $15;) and most likely die within a month or two if it's used a few times a day..
Stay away from that store if you wan't anything with quality. The only unit from them that might be ok for the money is their Thor brands..
 
GSS said:
NO NO it's toy grade gimmick meter that's not very accurate and probably worth $15;) and most likely die within a month or two if it's used a few times a day..
Stay away from that store if you wan't anything with quality. The only unit from them that might be ok for the money is their Thor brands..
Click to expand...

Ditto. Exactly right. Stay away from them--cheap is called cheap for real reasons.

Something for nothing does not exist anywhere in the world.

For good quality. accurate, reasonably priced LPMs look at Laserbee LPMs. Jerry the owner is a long time member here and stands behnd his products 100% see: https://www.laserbeelpm.com/products-1.html
 
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I made one 1 year ago and used SLD323VF if you read description you can see the message copy that person who bought it sent and what laser types he tested it by himself.. also you can find his ebay ID in my feedback history as a seller. and you will find out that he tested it against his another LPM and it was spot on.. however you do have a calibration Pot where you can fine tune it if necessary yourself, battery source is not good to be used as Power source unless regulated ... batteries tend to draw a lot of power at first but as they getting weaker and weaker output is dropping down too.. I have regulated voltage to a steady fixed 8v then second regulator to get the voltage down to what we need. 8 v makes sure that voltage coming into second regulator comes fine filtered and not dropping down... + lm317 current regulator.. I made a video of it.. read all on items page and I will provide a video link to you.. however thanks for your time replaying back, I appreciate it.. . I made a few PCB boards and tested it.. as you can see in pics
 
paul1598419 said:
This is a do-it-yourself meter and you will need some known laser sources for calibration if you decide to go this way. I would want to know much more about it before I would even consider this as viable.
Click to expand...

I made one 1 year ago and used SLD3232VF if you read description you can see the message copy that person who bought it sent and what laser types he tested it by himself.. also you can find his ebay ID in my feedback history as a seller. and you will find out that he tested it against his another LPM and it was spot on.. however you do have a calibration Pot where you can fine tune it if necessary yourself, battery source is not good to be used as Power source unless regulated ... batteries tend to draw a lot of power at first but as they getting weaker and weaker output is dropping down too.. I have regulated voltage to a steady fixed 8v then second regulator to get the voltage down to what we need. 8 v makes sure that voltage coming into second regulator comes fine filtered and not dropping down... + lm317 current regulator.. I made a video of it.. read all on items page and I will provide a video link to you.. however thanks for your time replaying back, I appreciate it.. . I made a few PCB boards and tested it.. as you can see in pics


this was not the one I sold a year ago it was one before I , made it for myself first and you can have a look how linear output is.. I have done this over , and over done some graphs at the time and when made second one I made it to sell one only ,guy that bought it was pretty happy with it..

Max output it can register, is 7000mw although all lasers over 100mw have to be not focused as otherwise will burn the sensor..
on 50mw laser would be 5-6%+- error although he had a Ophir I think and compared it to it in his tests he said it was spot on was 1-2% lower then Ophir . he had . my LPM could measure higher then his Ophir and was not off for more then 5mw on 100mw-200mw lower range. . but please bare in mind this is a hobby like LPM although I have made PCB board after a lot of errors and trials to make better performance then using proto-pcb-boards.. the hardest thing even if op amps have right gain is the sensor itself.. that is the final touch and very hard to generalise it..

Hope That helps.. Iike I said I made a few with lots of errors and trials and learned a lot through the process of making it and tweeking them.. However bare in mind this is a DIY Homemade Laser Power meter and I am sure it will serve the purpose especialy for stronger lasers over 3w,4w,5w up to 7w..

50mw 405nm test
Below is 445nm 2w tested
www.ebay.co.uk

LPM Laser power meter 7W it's a Diy Hobby like Laser Energy Meter | eBay

Find many great new & used options and get the best deals for LPM Laser power meter 7W it's a Diy Hobby like Laser Energy Meter at the best online prices at eBay! Free delivery for many products!
www.ebay.co.uk
 
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lasermore said:
Looking for cheapest functional LPM (laser power meter).
What is the best source/model for such?
Will this one work below at ebay?
www.ebay.com

Newport Model 1825-c Industrial Optical Laser Digital Analog Power Energy Meter for sale online | eBay

Find many great new & used options and get the best deals for Newport Model 1825-c Industrial Optical Laser Digital Analog Power Energy Meter at the best online prices at eBay! Free shipping for many products!
www.ebay.com
Click to expand...
Pretty sure you would need the optical sensor that goes with the meter. And being old and used it's probably not calibrated at all which would make it useless. Also it does not state which wavelength(s) it is able to read so you would have to do some research to see what the maxium power density rating is for the lpm and what wavelengths its capable of reading as many lpm's are designed or calibrated to read certain wavelengths sometimes very specific wavelengths only or very narrow bands of wavelengths. Not to mention you would have to somehow track down the power cords probably the optical sensor and whatever other peripherals that need to be connected to the ports assuming all the ports still work. And honestly optical sensing lpm's seem to be fazing out in favor for thermopile sensors which measure temperate change caused by the intensity of the laser which I believe allows for far greater bands of different wavelengths. Considering how easy it is to knock a older optical lpm out of calibration your better off buying a newer digital model and preferably one that dont require a optical correction factor chart.


Edit: hope this helps. You may get lucky and find a decent model on Ebay. Your probably better off going to the by sell trade section of this forum and asking if anyone has one for sale
 
Hi,
You get what you pay for in an LPM, That said go to Laserbee LPM and get a great LPM you'll have it for years to come. Go cheap go home..

Rich:)
 
foodson said:
I made one 1 year ago and used SLD323VF if you read description you can see the message copy that person who bought it sent and what laser types he tested it by himself.. also you can find his ebay ID in my feedback history as a seller. and you will find out that he tested it against his another LPM and it was spot on.. however you do have a calibration Pot where you can fine tune it if necessary yourself, battery source is not good to be used as Power source unless regulated ... batteries tend to draw a lot of power at first but as they getting weaker and weaker output is dropping down too.. I have regulated voltage to a steady fixed 8v then second regulator to get the voltage down to what we need. 8 v makes sure that voltage coming into second regulator comes fine filtered and not dropping down... + lm317 current regulator.. I made a video of it.. read all on items page and I will provide a video link to you.. however thanks for your time replaying back, I appreciate it.. . I made a few PCB boards and tested it.. as you can see in pics
Click to expand...
I just watched the video and have a few questions...

1) What is the minimum beam diameter and max power that
can be applied to your sensor's coating ( or it's Power Density) ??
2) What is the highest power Laser that you actually used to test
and calibrate your LPM ??
3) What NIST traceable LPM did you use to calibrate your LPM ??

Jerry
 
lasersbee said:
I just watched the video and have a few questions...

1) What is the minimum beam diameter and max power that
can be applied to your sensor's coating ( or it's Power Density) ??
2) What is the highest power Laser that you actually used to test
and calibrate your LPM ??
3) What NIST traceable LPM did you use to calibrate your LPM ??

Jerry
Click to expand...
Q & A
1)
What is the minimum beam diameter , not clear to me what do you mean,minimum beam diameter, means focused as only then you can have minimum beam diameter and in that case you should not test any laser when focused to minimum beam diameter, max beam diameter is 15mm, radius 7.5mm.
lasers have to be not focused recommended, same is with laserbee. up to 200mw can be even focused i tested it and it does not affect its operation although unfocused is the best practice... little bit off focus will do.... max power I tested is 2000mw I had no laser over that power..

2) like I said 2000mw

3) i did not use it, like I said I am not manufacturing this I made one 1 year ago with lots of errors and trials and a few for myself.. only one I sold and guy was over the moon, can read his feedback and tests hes done on items page... have a look another video out of those 2 and another one was testing a 2w laser 445nm... I noted it's hobby like but it will do what you would expect a hobby like lpm to do.. mAX OUTPUT IT CAN measure unfocused with beam no bigger then lets say 12mm x 12mm save to go instead to the edge of 15x15mm and sensor should be fine to stand up to 7000mv on fresh set of batteries..

hope that was as honest as it can be and answers all your questions..

maybe after you could be next one to give me a good review too :)

if you are up for a challenge send me your lowest range or cheapest lpm meter and I will do a test video comparing it to mine
and rest of the people can send their lasers to be tested including return postage labels, or i will get myself some lasers to be tested just so we can do a comparison...
I will return your meter back to you and it could be fun to find out if it's worth or not.. what do you say sir ?

I am not a novice when it comes to opams and circuits..

regardless of circuitry and components used ,gain etc. just wrong level of coating over the sensor could change whole circuit design..
it could simply make it look like there is not enough gain or the other way around .. so you know sir with hand on your heart even if post my circuit out ,the final version, it would be very hard for anyone to get everything just right. sensor really makes the difference a lot..
and you yourself know this too... I spent a lot of my free time testing, probing and working on errors .. and for someone who is not a electronic guy it will be pretty difficult if they just simply lay-down components and expect circuitry to work just like that.. perfection takes time and I know this subject now a lot better Jerry ... hope this was as good as you expected it to be...
may I ask Jerry kindly : do you send every unit to NIst .. hand on your heart Sir, I doubt it truly and honestly.. you may use a unit as some sort of reference for your calibration but if you send every unit yourself to nist price would have to be huge.. even big and huge companies don't do that.. they calibrate it by them-self by using known source references..
www.ebay.co.uk

LPM Laser power meter 7W it's a Diy Hobby like Laser Energy Meter | eBay

Find many great new & used options and get the best deals for LPM Laser power meter 7W it's a Diy Hobby like Laser Energy Meter at the best online prices at eBay! Free delivery for many products!
www.ebay.co.uk
 
Last edited:
foodson said:
Q & A
1)
What is the minimum beam diameter , not clear to me what do you mean,minimum beam diameter, means focused as only then you can have minimum beam diameter and in that case you should not test any laser when focused to minimum beam diameter, max beam diameter is 15mm, radius 7.5mm.
lasers have to be not focused recommended, same is with laserbee. up to 200mw can be even focused i tested it and it does not affect its operation although unfocused is the best practice... little bit off focus will do.... max power I tested is 2000mw I had no laser over that power..

2) like I said 2000mw

3) i did not use it, like I said I am not manufacturing this I made one 1 year ago with lots of errors and trials and a few for myself.. only one I sold and guy was over the moon, can read his feedback and tests hes done on items page... have a look another video out of those 2 and another one was testing a 2w laser 445nm... I noted it's hobby like but it will do what you would expect a hobby like lpm to do.. mAX OUTPUT IT CAN measure unfocused with beam no bigger then lets say 12mm x 12mm save to go instead to the edge of 15x15mm and sensor should be fine to stand up to 7000mv on fresh set of batteries..

hope that was as honest as it can be and answers all your questions..

maybe after you could be next one to give me a good review too :)

if you are up for a challenge send me your lowest range or cheapest lpm meter and I will do a test video comparing it to mine
and rest of the people can send their lasers to be tested including return postage labels, or i will get myself some lasers to be tested just so we can do a comparison...
I will return your meter back to you and it could be fun to find out if it's worth or not.. what do you say sir ?

I am not a novice when it comes to opams and circuits..

regardless of circuitry and components used ,gain etc. just wrong level of coating over the sensor could change whole circuit design..
it could simply make it look like there is not enough gain or the other way around .. so you know sir with hand on your heart even if post my circuit out ,the final version, it would be very hard for anyone to get everything just right. sensor really makes the difference a lot..
and you yourself know this too... I spent a lot of my free time testing, probing and working on errors .. and for someone who is not a electronic guy it will be pretty difficult if they just simply lay-down components and expect circuitry to work just like that.. perfection takes time and I know this subject now a lot better Jerry ... hope this was as good as you expected it to be...
may I ask Jerry kindly : do you send every unit to NIst .. hand on your heart Sir, I doubt it truly and honestly.. you may use a unit as some sort of reference for your calibration but if you send every unit yourself to nist price would have to be huge.. even big and huge companies don't do that.. they calibrate it by them-self by using known source references..
[/URL]
Click to expand...
The reason that I ask "what minimum beam diameter at what max power" is
to know the max Power Density of your coating that you claim is 7Watts.

Our lowest power LaserBee AX is rated at 3.1W and in the instructions it
is stated that a minimum beam diameter of 3mm at maximum 3.1W is
the maximum power that our sensor coating for that LPM can take without
damage. That is a realistic 45.2 W/cm2.

If we use your stated expanded beam size diameter of 12mm at your stated
Max 7watts... that would make your Max beam density only 6.19 W/cm2...
or at a 3mm diameter beam a max power of 433mW could be applied before
your coating would be damaged (using your information).

If we used an expanded beam diameter of 12mm as our beam diameter on
a Laserbee AX we could in effect state a max power of ~51 Watts instead
of our realistic 3.1W rating.

Using Power Density allows one to compare oranges with oranges...

We purchased a brand new NIST traceable Coherent LPM so that we can
accurately calibrate our LaserBee LPM products. Our LaserBee LPM products
are not sent to NIST to be calibrated.

Asking us to send you a Free of Charge LaserBee LPM so that you can have
a reference to calibrate your LPM just doesn't sound logical to us.
You are however welcome to purchase a LaserBee product at any time.

Jerry
 
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