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

[GSS]

Thank you.. always wanted one and just could never get one. I have some units measured by others that would be nice to compare to..
Oh yes I will sure post about

 

[foodson]

Thank you.. always wanted one and just could never get one. I have some units measured by others that would be nice to compare to..
Oh yes I will sure post about

then start conversation in top menu with me and pass me your address and full name so I can send it signed for , to you, and we will take from there..

 

[foodson]

This 7000mw DIY LPM has been sent to member GSS.
Also I have done the test on 7W laser diode from Laser Engraver/Cutter and if you look at the video it measured 6.85W no probs what so ever..

LMP is out and on it's way to GSS..
Please don't message anymore as I have sent it out and no longer have it.. Thanks to all of you ..
For mr Jerry - >Please don't contact me nor replay to posts not merely relate yourself to it.. you said enough to me I did not like any of it.. it was very rude .. . .

 

[Lifetime17]

Hi, One question why were you moving the beam up and down on the LPM. That should be about 8 to 10 inches from the LPM and directed in the center for a good reading. When the beam is hitting the sides of the LPM surface your readings will fluctuate.
Just curious , do you have a hand tremor I don't know. Glad to see that you shipped it to a great member very nice the gesture.

Rich

 

[lasersbee]

This 7000mw DIY LPM has been sent to member GSS.
Also I have done the test on 7W laser diode from Laser Engraver/Cutter and if you look at the video it measured 6.85W no probs what so ever..

LMP is out and on it's way to GSS..
Please don't message anymore as I have sent it out and no longer have it.. Thanks to all of you ..
For mr Jerry - >Please don't contact me nor replay to posts not merely relate yourself to it.. you said enough to me I did not like any of it.. it was very rude .. . .

Since you insist on calling me out by name... I will respond.

1) You show a Laser that you claim is 7Watts.
Where is the Laser being power tested on a know recently
calibrated good LPM to show it is really 7W ??

2) You shake that Laser all over the sensor surface without
showing the diameter of the beam. Is that so the Laser's
beam does not burn the coating if left on the same area of
the Sensor's active area ??

3) In your last video I can see that the Active surface of your
sensor is not pristine and seems to have been blemished or
scorched near the center (@6:05)

3) Your sensor head does not have enough mass to be cooled
by the heatsink sufficiently with the claimed "7 watt" laser
beam on it.
Watching your other video we see that you do not have an
accurate LPM to calibrate your LPM.

You merely used the Laser Diode spec sheet A/W numbers
to calibrate your LPM with 48mA of current running to the
Diode. And that we can not tell if it is the current directly to
the LD or the current the Diode Driver is drawing.

In the Video you show a current of 48mA and adjusted your
LPM to read 48... (@6:05) And when you dropped the current
to 43mA the LPM reading was only 40... (@7:09).
Quite an error of non linearity... 3mW on a 5mW change...

[EDIT]
Looking at the datasheet for the SLD3232VF that you used
for the calibration of that meter it seems that the slope
efficiency can not be relied upon for calibration because
the datasheet states that the slope can be from 0.9W/A to
1.8W/A. There is no way that your LPM is accurate to your
claimed 5%-6% error in Post #11 using this method.


@rich.. You are absolutely correct. Any knowledgeable person
that uses Laser Power Meters know that you don't shove a high
powered lasers right up to a Thermopile Sensor.


Jerry

 

[lasersbee]

I almost forgot to mention this....
Here are some DIY LPM projects for those of you that
want to build your own.....

https://laserpointerforums.com/threads/diy-laser-power-meter-projects.71234/#post-1026292

I looked at the schematics of the foodson LPM and
it looks a lot like the MarioMaster $50 LPM project
from way back in 2010.

Jerry

 

[GSS]

Ok, it's been a while since member "Foodson" sent me his DIY LPM for the price of shipping from the UK.
I promised to give a honest review, "really more of a opinion as I don't have the knowledge and also can't post a video"
Brought it back to this thread as all the internals, spec's, and pieces are mentioned here from knowledge LPM makers and owner's.

Most important thing to mention is that this meter has been in the same room with a stable temp and the lasers used focused wide, but not wide enough to hit the heatsink that the sensor is on, about 3 to 8 inches away. Plenty of cool down time in between any unit regardless output of high or low.
I wish I could give a good first impression but I can't.. It's kinda a crap shoot to what it would do every time when first turned on.
Ok, right of from the first start when receiving it I noticed the 10 turn Offset knob didn't do anything. The meter stood at 0.000 and wouldn't go into the negative nor positive.. Switching the LPM between on and off somewhat repeated I did and could get the Offset to work but only to the positive.
In between these turn off and on attempt's when it was on every now and then the meter would just randomly throw out numbers from 5mw to 500mw and never stabilize to 0.000 even after 5 or 10 minutes.

My first try was a 1.1W 520 that I received the same day from Lifetime. It metered at 2W at one point on this LPM but didn't stabilize and fluxuated at least + or - 200mw's.
Switched to a blue 445 M140 at 1.6A and 3 element lens and it metered at 2.8W and same fluxuation.
It would not meter or register a reading on lasers at under 200mw after these above^^^ tests after even a significant 30 minute cool down.
Other days it would register a low power green or red pen at times. Since the Offset did nothing the majority of the times, I would turn it all the way back and turn it clockwise 5 times as it's a 10 turn pot "hoping" it was somewhat "centered"??
One example was using a red pointer from Pman that he metered at 110mw, I would turn the Offset back till the this red laser finally registerd and it would hit around 180mw. Turning the offset back I could get this pen to read 110mw, "trying" maby to calibrate this lpm but it still after this it would read very high on higher powered lasers..
I knew all along this is not a way to calibrate a meter but at this point it was just a playing game.
It has a calibration pot which I haven't touched and "Foodson" "did really' try to walk me through it but in all honesty I can't understand or read schematics and circuit numbers at this point. A DIY electronic knowledged person might be able to set it and work with it but not me as I was hoping a more plug in and play LPM.

The first 3 pic's are just showing it randomly flashing numbers at one of the first turn on's and continued till I shut it off.

The 3rd and 4th is turning the Offset and trying to register,

Then showing the 1.1W 520 and a 1.5W reading high and still climbing.

Again showing the M140 at 1.6A and 3 element lens at 2.3W and climbing.

Then a few inners..

Now if i'm doing something wrong I need to know..
I'm not here to knock Foodson and feel like it just might work. There were a few exposed wires and felt it could of been a bit cleaner wire wise and soldering inside.

 

[lasersbee]

Ok, it's been a while since member "Foodson" sent me his DIY LPM for the price of shipping from the UK.
I promised to give a honest review, "really more of a opinion as I don't have the knowledge and also can't post a video"
Brought it back to this thread as all the internals, spec's, and pieces are mentioned here from knowledge LPM makers and owner's.

Most important thing to mention is that this meter has been in the same room with a stable temp and the lasers used focused wide, but not wide enough to hit the heatsink that the sensor is on, about 3 to 8 inches away. Plenty of cool down time in between any unit regardless output of high or low.
I wish I could give a good first impression but I can't.. It's kinda a crap shoot to what it would do every time when first turned on.
Ok, right of from the first start when receiving it I noticed the 10 turn Offset knob didn't do anything. The meter stood at 0.000 and wouldn't go into the negative nor positive.. Switching the LPM between on and off somewhat repeated I did and could get the Offset to work but only to the positive.
In between these turn off and on attempt's when it was on every now and then the meter would just randomly throw out numbers from 5mw to 500mw and never stabilize to 0.000 even after 5 or 10 minutes.

My first try was a 1.1W 520 that I received the same day from Lifetime. It metered at 2W at one point on this LPM but didn't stabilize and fluxuated at least + or - 200mw's.
Switched to a blue 445 M140 at 1.6A and 3 element lens and it metered at 2.8W and same fluxuation.
It would not meter or register a reading on lasers at under 200mw after these above^^^ tests after even a significant 30 minute cool down.
Other days it would register a low power green or red pen at times. Since the Offset did nothing the majority of the times, I would turn it all the way back and turn it clockwise 5 times as it's a 10 turn pot "hoping" it was somewhat "centered"??
One example was using a red pointer from Pman that he metered at 110mw, I would turn the Offset back till the this red laser finally registerd and it would hit around 180mw. Turning the offset back I could get this pen to read 110mw, "trying" maby to calibrate this lpm but it still after this it would read very high on higher powered lasers..
I knew all along this is not a way to calibrate a meter but at this point it was just a playing game.
It has a calibration pot which I haven't touched and "Foodson" "did really' try to walk me through it but in all honesty I can't understand or read schematics and circuit numbers at this point. A DIY electronic knowledged person might be able to set it and work with it but not me as I was hoping a more plug in and play LPM.

The first 3 pic's are just showing it randomly flashing numbers at one of the first turn on.

The 3rd and 4th is turning the Offset and trying to register,

Then showing a 1.1W 520 and a 1.5W reading high and still climbing.

Then a few inners..

Now if i'm doing something wrong I need to know..
I'm not here to knock Foodson and feel like it just might work. There were a few exposed wires and felt it could of been a bit cleaner wire wise and soldering inside.

From what I read... You didn't do anything wrong.
You didn't touch the Calibration Pot and only played
with the Offset Pot which would be the Zeroing
control.
Foodson Knocked himself with all his Bragging and
and whining and having nothing to show for it.

An LPM with a split supply like he touted about it
should easily be able to take the Zeroing readings
on the display from a Negative value through Zero
and up to a Positive Value with no input to the sensor.

Not only that... the readings even if not calibrated
properly should be stable and repeatable... unlike
the LPM you seem to have been saddled with.

The wiring in that LPM is atrocious for the amount of
bragging he did here... not professional in the least.
That last inside wiring pic says it all.......

THERE IS NOTHING TO BE JEALOUS ABOUT HERE......

No wonder he hasn't posted since he pawned that
junk off on you. I feel for you GSS.....

Jerry

 

[GSS]

Can I do anything with this unit?
Lower power laser testing??

 

[BowtieGuy]

Thanks for the update on your LPM, I've been wondering if you ever received it, and if it worked properly.
It's too bad that it doesn't work worth a damn, unfortunately you still need a working LPM.
Like Jerry mentioned, that's one nasty looking "rats nest" of a wiring job in that unit. ☹

 

[CurtisOliver]

I'm concerned by the lack of activity of the seller. Also the arguing in this thread, I can't be bothered to read tbh. But not exactly professional of him. Peter, I thought it was great that you finally got an LPM. But this is not exactly what I was hoping for you. I hope you come to some resolution, but I'm not feeling that you will. Did you get any details of this guy? If so, don't post them here though.

 

[GSS]

I'm concerned by the lack of activity of the seller. Also the arguing in this thread, I can't be bothered to read tbh. But not exactly professional of him. Peter, I thought it was great that you finally got an LPM. But this is not exactly what I was hoping for you. I hope you come to some resolution, but I'm not feeling that you will. Did you get any details of this guy? If so, don't post them here though.

Oh he was in constant communication with me through PM's.
Problem is I couldn't understand as to what meant what "electronicly" tech wise.
Maby he assumed I knew more about resistor's, ohm's etc. etc. I did not touch nor want to touch the "cal pot"
I wanted and thought it was more a ready to go unit, and I really don't believe anything happened to it in shipping..
If it was somewhat close to any kind of consistentsy and say averaged maby 100mw high I might be able to live with it.
Hey, it was I think around $37 in shipping so no big loss..

 

[Lifetime17]

Can I do anything with this unit?
Lower power laser testing??

Hi GSS
Ok I know what to do with it but don’t ask
Ok the real deal is if you want a real LPM I will give you one for free let me know buddy
Rich

 

[CurtisOliver]

You might not of spent a lot, but it's not exactly usable with such large inconsistencies. You don't want to be calibrating it constantly on nearly every laser you test.
I can see he's been on 8 days ago.

Edit: Very generous offer of Rich there.

 

[lasersbee]

Just logged on and saw the Thread posts
and saw Rich's offer. Very generous Rich.
GSS... I had already just PMed you with an
offer as well. Looks like it's raining LPMs.

Jerry

 

[CurtisOliver]

Cool, its due to rain here too. But with water.
Nice generosity displayed by you both.