Homemade Laser Power Meter - Experiment 

Electroplating is super easy. You can even plate your 3dprints. So for that peltier I would spray it with clear glaze and while it's wet you put it in a sealed container with fine graphite powder and give it a shake. Don't open the container right away. Graphite is very messy, wear a mask and if you do it inside do it in the bathroom, run the hot water in the shower to raise the humidity and this will keep your particles from going all over but in this case since we aren't playing I would take it outside and make sure the coverage is good and then let it dry outside. Start with less powder and add as you need. Wipe your surfaces off with alcohol before application but give the part some good squirts of clear. It should be easy to get a uniform layer on something as flat as that peltier. Don't do the mix your wets and drys together. The 2 mixed together block each other's most valuable properties. One sticky layer and then one matte black conductive layer gives you all the sticky while retaining the high conductivity of the graphite. Plating 3d prints means submerging them in a solution of vinegar, salt , and whatever you want to plate with. Nickel is quite good and you get to find out if those cheap nickel strips you bought are just nickel plated steel or the real deal.

Very nice project. Just one question - why not heat up the cold side of peltier with resistor, and simultaneously apply laser to hot side? the balance point in this case is zero voltage. At first, it is easy to detect, and second - you don't need 2 cycles of consequent measurement as you do it now (first with light, second with resistor)?

Since the laser "target" is not 100% absorptive, there can be a significant amount of reflected laser light. Laser safety is quite important. Making sure you wear protective glasses or, along with other's suggestions for using insulation, maybe make an enclosure to prevent the reflected light form damaging your eyes.

Very interesting project. I am afraid that the heat dissipation from the Peltier element is different at the edge than in the center. It might be useful to heat the Peltier element in the middle when creating the characteristic curves. I am also afraid that the heating emits an enormous amount of energy into the air. Insulation might be useful. Then only the reflecting laser light is undefined and can be compensated for in the code. I have another idea for a laser meter. Why don't you place a small heating element on the back instead of the heat sink? Then let the microcontroller regulate the heating via PID so that 0V comes out at the Peltie element. This gives you pretty much the exact heat output that the laser puts into the element.

Use an enclosure with mirrored internal sides to return any reflected light back to the sensor. It should help the efficiency. Mirrored perspex is available and easy to machine.

That's really cool!! Awesome project and great editing!

Also .. companies lie. There's zero guarantee you'll actually get what the label says, even on big name brands.

such an awesome channel! Very creative use of electronics knowledge.

Very interesting! I wonder how comercial testers work. Perhaps a thermocouple junction? I wonder, could you shine the laser on one side of the peltier, have the heater resistor on the other side, and adjust the heater power until the peltier balances and outputs zero volts? Oh also try dusting the surface with the toner powder then heating it with a hot air gun to melt and fuse it to the peltier :D

Wow very thorough explanation, you anticipated all my questions. I wonder about some of the new "super dark" black coatings like Action Lab explored... vanta black, I forget the other ones

muchas gracias Master saludos desde Cali-Colombia

Very interesting and new project nobody have thought off I like it bro ❤❤

interesting experiment. I'm sure that you finish the project very very welllll

Nice project

Thanks, Your project is very interesting, I think that regarding the black paint you need, toner is not a good idea, because it has plastic particles, black glass fusion powder would be better. a big greeting from Argentina

Nice video as always

Consider to measure the speed of the increasing value instead of waiting for equilibrium, this ll give instant value without waiting for it to reach the maximum. To do this you have to plot the speed instead of the max as reference for your calculation

very good plan❤

Interesting post..

Great idea, i am curious ;-)

Thank you!

Seems much simpler to Get a piece of black anodized aluminium heatsink. Add a thermocouple in a small hole. Weigh the aluminium. Optional, for better accuracy:- cover the back and sides of heatsink with some thermal insulator like expanded polystyrene, leave one face open. Blast the black open face with your laser and see how much it heats up in say 20 seconds (time can vary for better accuracy or different powered laser). Multiply the temperature change (in celsius) by 0.902 x (weight in g) and divide by (the time in seconds). 0.902 J/g ° C is the specific heat capacity of aluminium. This is the power absorbed by the heatsink as supplied by the laser in Watts. I have several of these, I use a cheap battery powered digital thermometer. Accuracy is affected by the heat conducted away into the air during heating and by how well the black anodised aluminium absorbs heat. I calibrated it with a commercial power meter and found this to be reasonably close. You can (sort of) calibrate it with a resistor or transistor clamped to the heatsink that heats it up and since you know the power doing the heating it means you don't have to weigh the heatsink piece. At least now I can see if my laser is losing power.

thats a 30 minute thank you

I'm skeptical that the system shown in the video will suffice for measuring my optical power, which won't exceed 5 mW. What alternatives should I explore?

Use reflow oven and the plastic dust or that some dust you have Similar to powder coating There are lot of videos available about how to do powder coating

You should probably leave the laser right where it is when you switch to electric heating. The presence of the laser changes the air flow around the heat sink in the random air currents of the room. Or perhaps switch to forced air flow

How come you didn't get a little sample of vanta black?

You misunderstand the substances you are working with. Printer toner is a plastic (probably with candle-soot carbon black in it). You want it to adhere to the peltier cell, just melt it on. You didn't try the UV cure resin because you think that won't withstand the heat, and I think that is incorrect also. Graphite from the pencil is a shiny gray color. That's just what it is. You're probably thinking it should be carbon black, which you already exemplify with the candle soot. It's just black spray paint on those aluminum sheets, you could just spray black spray paint on the peltier module and you get rid of one lossy interface entirely.

13:23 "The Celtier Pell" 🤣🤣🤣

Why not using solar cell

The hole in the heater should be rectangular in shape.

❤

nice one bro but we need an exciting project like a cannon or a tank.(AI included)

Why don't you use LDR - light-dependent resistor ? You can claculate the luminosity instade of watt because light is measured in lumen

Get a Calibrated Laser Power Meter...

Пельтье нельзя использовать для охлаждения из-за его физического принципа работы, гораздо проще поставить алюминиевый радиатор или водяное охлаждение.