This could be useless if the light of your LASER was not absorbed, because the water is transparent for many ranges of wavelenghts. By other hand, you can have a instant evaporation of water in the surface, before the increase of temperature.
The max amperage in the peltier cell affects the millivolt reading in my testing I've tested 1,2,6,8,10A cells in my testing 6A cell gets the closer reading
What size laser were you testing with the 6A cell? If I want to test lasers that are less than 1W, would a lower Amp cell be more accurate than the 6A?
I had been wondering if this was possible. I'm surprised at how little drift occurs. I wonder if you could use a second peltier and a thin film sensor to act as a fixed temperature reference. Nice work!
the only reason they have been placed at different distances is because they have different focusing distances, and you need to point it at the peltier cell - not in focus - otherwise you burn the cell.
@LaserGRBL great video! Can you tell me is there any difference if the heatsink is mounted to the hot or the cold side? Or just the output voltage is inverted?
Your method will be very useful to me. For some time I will have an Ophir meter and will be able to calibrate the Peltier using it. I have a question: What does the black absorbing plate, which is pressed against the Peltier element, consist of?
@@lasergrbl Good stuff.... Hope you also used a thermal grease - DOW # 340 is good - to make sure good thermal conductivity between the cell and heat-sink....
It's an interesting video. But I miss the direct comparison with the laser power meter you bought. Could you also explain the use of the laser power meter? Do you remove the lens for the measurement?
In the video there is no comparison between the LPM and the peltier, but I can say that the two modules make about 5.4W and about 7W when measured with the LPM so the 0.540mV and the 0.680mV can be considered representative. It is not necessary to remove the lens, the important thing is that it does not focus on the LPM or the cell, otherwise it will burn. Obviously the lens introduces a power loss, usually around 10% (it depends on the quality and type of the lens) so if you want to measure the power of the diode you have to remove it, if you want to measure the real power that will end up on the material to be engraved you have to put it. The difference between the two tells you the dispersion due to the lens.
You could have at least placed a load resistor on the output of the module and see how much current and therefore power the module makes compared to the laser. But you didn’t.
@@lasergrbl Not a problem, in fact you could make an entire video on it. Just place a resistor across the module. Divide voltage by resistance and that will give you current. Then of course voltage x current = wattage or power. You don’t even need a meter except to measure voltage. If you place a meter in series between the module output and resistor it will be exactly the same as you calculated. This is the great thing about ohm’s law in which if you know any 2 things out of 3 then you will figure out the third thing. I’m really actually curious as to what the module’s power is compared to the 5 watts of the laser. To find efficiency simply divide output by input then multiply by 100. Next is to try a magnifying glass between the laser and module. This will amplify the heat to the module. It may not improve things or it may I wouldn’t really know, but I’m curious!
Intresting video. I made test to myself, but i dont know what to thing.... I have NEJE laser modul wich shuud have 7.5w optical power, but when i measure voltage from Peltier cell, it shows only 0.22v.... This doesnt seems right...
exact voltage depend on peltier specific model, and quality of surface black painting (should be not reflective). however it is a comparative measurement, not an exact one. I mean you can compare laser power of two different diode and have an approximate measurement of "how much or how less is powerfull one respect the other" but not an exact/absolute measure.
@@lasergrbl i see.i tested again with two laser moduls and It dosapointed me, that one laser modul 2.5w had 0.14v, and neje laser modul 7.5w only 0.24v... but shud be three times stronger...
Hello sir this is Marky Ric, il post the same project that i will make on my page and here on my channel for this DIY laser power meter using Peltier cell ;)
@@lasergrbl thanks. That exact one had actually caught my eye for use with a NUBM44 build I'm planning, but I wasn't sure of it's quality. You've given me the last piece of the puzzle!
@@marcellusjon1424 well, the one I received only give 4.4A I had to change the feedback resistor to get it work at 5A. I hope it was a problem only of my board
@@lasergrbl I think 4.4A would work perfectly for me. I want a little more power of course, but my main priority is longevity. I don't want my engraver to burn out within only a few months. Great tip about the Peltier cell too!
Hello! I bought a laser power meter. In the video you talk about the laser beam not in focus and without lenses. So to measure for example a 15W neje of optical power how should I place it in front of the sensor? The instructions (in Chinese) indicate a maximum beam of 8 millimeters. I measured my lasers focusing on the sensor (narrower beam on the probe). How long do I have to hold the beam to get a correct reading? Thanks so much!!
Beam should be not in focus, or it damage the sensor. Keep it as long as you read the peak, than the measured power start decreasing, peak is your power. Be care that this instruments has a max value that can read, don't exceed.
Cool! This is better than my idea of shining the laser at a black plate in a bath of water and measuring the water's temperature change.
This could be useless if the light of your LASER was not absorbed, because the water is transparent for many ranges of wavelenghts. By other hand, you can have a instant evaporation of water in the surface, before the increase of temperature.
The max amperage in the peltier cell affects the millivolt reading in my testing I've tested 1,2,6,8,10A cells in my testing 6A cell gets the closer reading
What size laser were you testing with the 6A cell? If I want to test lasers that are less than 1W, would a lower Amp cell be more accurate than the 6A?
I had been wondering if this was possible. I'm surprised at how little drift occurs. I wonder if you could use a second peltier and a thin film sensor to act as a fixed temperature reference. Nice work!
BRILLIANT! THAT'S AWESOME!!
The distance you kept the different lasers away from your measuring device way different . Would that make a difference?
no noticeable difference as the laser power does not disperse with distance (unlike what happens with the light of a bulb)
th-cam.com/video/vUwP7SY0Ajs/w-d-xo.html
the only reason they have been placed at different distances is because they have different focusing distances, and you need to point it at the peltier cell - not in focus - otherwise you burn the cell.
@LaserGRBL great video! Can you tell me is there any difference if the heatsink is mounted to the hot or the cold side? Or just the output voltage is inverted?
Super, thanks.
Please tel me where from can I buy this Peltier Cell including the thermal shield. Mouser is selling only the cell.
AliExpress
Your method will be very useful to me. For some time I will have an Ophir meter and will be able to calibrate the Peltier using it. I have a question: What does the black absorbing plate, which is pressed against the Peltier element, consist of?
laser side is painted black, cold side is pressed on an aluminum heatsink (from an old PC graphic card)
@@lasergrbl Good stuff.... Hope you also used a thermal grease - DOW # 340 is good - to make sure good thermal conductivity between the cell and heat-sink....
It's an interesting video. But I miss the direct comparison with the laser power meter you bought. Could you also explain the use of the laser power meter? Do you remove the lens for the measurement?
In the video there is no comparison between the LPM and the peltier, but I can say that the two modules make about 5.4W and about 7W when measured with the LPM so the 0.540mV and the 0.680mV can be considered representative. It is not necessary to remove the lens, the important thing is that it does not focus on the LPM or the cell, otherwise it will burn.
Obviously the lens introduces a power loss, usually around 10% (it depends on the quality and type of the lens) so if you want to measure the power of the diode you have to remove it, if you want to measure the real power that will end up on the material to be engraved you have to put it. The difference between the two tells you the dispersion due to the lens.
@@lasergrbl Thank you very much for the explanation.
Thank you. That helped me answer a question I had in my head :) Cheers from So.Ca.USA 3rd House On the Left
Hello, thank you for the video! Can you please tell me a equation i can use to transfer voltage to mW if i Use different peltier cell? Thank you.
You could have at least placed a load resistor on the output of the module and see how much current and therefore power the module makes compared to the laser. But you didn’t.
thanks for your hint, I think you're right. using a load resistor and measuring V and I certainly give better readings
@@lasergrbl Not a problem, in fact you could make an entire video on it.
Just place a resistor across the module.
Divide voltage by resistance and that will give you current. Then of course voltage x current = wattage or power.
You don’t even need a meter except to measure voltage.
If you place a meter in series between the module output and resistor it will be exactly the same as you calculated.
This is the great thing about ohm’s law in which if you know any 2 things out of 3 then you will figure out the third thing.
I’m really actually curious as to what the module’s power is compared to the 5 watts of the laser.
To find efficiency simply divide output by input then multiply by 100.
Next is to try a magnifying glass between the laser and module. This will amplify the heat to the module.
It may not improve things or it may I wouldn’t really know, but I’m curious!
Intresting video. I made test to myself, but i dont know what to thing.... I have NEJE laser modul wich shuud have 7.5w optical power, but when i measure voltage from Peltier cell, it shows only 0.22v.... This doesnt seems right...
exact voltage depend on peltier specific model, and quality of surface black painting (should be not reflective). however it is a comparative measurement, not an exact one.
I mean you can compare laser power of two different diode and have an approximate measurement of "how much or how less is powerfull one respect the other" but not an exact/absolute measure.
@@lasergrbl i see.i tested again with two laser moduls and It dosapointed me, that one laser modul 2.5w had 0.14v, and neje laser modul 7.5w only 0.24v... but shud be three times stronger...
Hello sir this is Marky Ric, il post the same project that i will make on my page and here on my channel for this DIY laser power meter using Peltier cell ;)
Did you ever make your DIY laser power meter using Peltier cell video?
Which laser driver did you use for your NUBM44?
Google "5A SCU driver"
@@lasergrbl thanks. That exact one had actually caught my eye for use with a NUBM44 build I'm planning, but I wasn't sure of it's quality. You've given me the last piece of the puzzle!
@@marcellusjon1424 well, the one I received only give 4.4A I had to change the feedback resistor to get it work at 5A. I hope it was a problem only of my board
@@lasergrbl I think 4.4A would work perfectly for me. I want a little more power of course, but my main priority is longevity. I don't want my engraver to burn out within only a few months. Great tip about the Peltier cell too!
@@lasergrbl Which resistor is to change to reduce the amps?
Hello! I bought a laser power meter. In the video you talk about the laser beam not in focus and without lenses. So to measure for example a 15W neje of optical power how should I place it in front of the sensor? The instructions (in Chinese) indicate a maximum beam of 8 millimeters. I measured my lasers focusing on the sensor (narrower beam on the probe). How long do I have to hold the beam to get a correct reading? Thanks so much!!
Beam should be not in focus, or it damage the sensor. Keep it as long as you read the peak, than the measured power start decreasing, peak is your power.
Be care that this instruments has a max value that can read, don't exceed.
Very costy.
Turned the video off when I heard your weird accent
What's your accent like?
@@Ignazio-ez8zs nomal