Open Source Laser Power Meter

ARGMeter the Open Source Laser Power Meter

ARGMeter is an open source laser power meter platform for the Arduino. The goal of this project is to give hobbyists access to a DIY LPM design for only the cost of hardware that they can expand and modify to suit their needs. This project has been through many prototypes and many designs, and is finally ready for release.
Rather than clutter up a thread will all the details I put everything on a website for anyone to use. https://sites.google.com/site/arglaserpowermeter/home
The project is continually under design and additions are made daily, if you see a bug or mistake please PM me or post here so that I may change it.

http://i.imgur.com/k9EkuAR.png

Features

* Ophir 20C-A and TEC compatible
* Real time data logging via PC or MAC
* 2.5" Liquid Crystal Display
* Full backlight control
* Zeroing
* Peak power
* Run with 9V battery or a 9V AC plug pack
* Up to 0.1mW resolution
* Up to 60 measurements per second

TEC (Will vary based on TEC and paint used)
* 3.5W max
* 30s response time (0-95%)
* 50W/cm^2 max power density
* <1mW noise
* 400-1100nm
* True curve adjustment

Ophir 20C-A
* 4W max
* 0.8s response time (0-95%)
* 0.5mW noise
* See datasheet for full details.

Schematic/Material/Firmware

https://sites.google.com/site/arglas...=400&width=347
All documentation of ARGMeter can be found here: https://sites.google.com/site/arglaserpowermeter/home

Licensing

ARGMeter is released under the terms of the GNU GPLv3. For more information, see the official site.
The GNU General Public License v3.0 - GNU Project - Free Software Foundation (FSF)

This is very interesting. Might have to build me one of these.

They went belly up IIRC....

Jerry

I'm very interested

Quote:

Originally Posted by sinfocomp

Hello, after much fidling with arduino, i managed to build my own laser power meter, it works based on calorimetry fundamentals and seems stable enough to read my 15 to 150watt Co2 lasers, anyone interested ?
cheers

Just a few basic questions.....

What is the lowest power it can measure accurately ?
What is the reading resolution and LPM accuracy % ?
What is the current draw ?
What is the sensing element and coating to get to a
150 watt rating ??

Jerry

confused

150w ??
First what is w?
do you mean 150mW??
also this thread is 5years old.. so ...a necro .
BUT nice that you are working on new LPMs ..

just try to use these=(Mw=W w, MW & mW ) correctly..

Quote:

Originally Posted by hakzaw1

150w ??

Yes, he really means 150 watts Len. :rolleyes: I guess you missed his other thread where he was talking about re-gassing a bunch of CO2 lasers.

150 watts might be high for a visible light laser, but it's nothing for a CO2 laser; depending on the model, they go into the KW. (Although for the sealed-tube, electrically-excited glass units he's working with, 150 watts is on the high end.)

Back on topic: I'm curious about the estimated final cost of one of these meters... ;)

Adam

... yes, 150 Watts for a CO2 laser is no problem -- I'm using single NIR laserdiodes with CW-powers of 30 Watts or "bundled" with up to 180 Watts (6x30W on a spot of 0.3mm diameter), what's too hard to measure at full powers with my actual power meter.

Have some "Ulbricht-spheres" with a sensor inside and plans to replace the sensor for CW-powers of up to 1kW, what's the next "power-range" I'm assembling units for.

Could be, next year I have to get somethig with more precise measuring in the range of 100 Watts to 3kW for welding tests with fiber- and CO2-lasers with 3kW and 5kW, what's not so easy with the commercial power-meters ... so too interested in a DIY-concept :cool:

Viktor

Hi Ed;

$25 is a lot less than I was expecting! Great work on your part. :)

Adam

How much do you expect?

Guys,
I had a DIY LPM.
Carbonsoot absorbent on 8x8mm TEC element with a simple cold compensation electrical circuit and a specific calibration process.
It worked great and accurate .
Than i've bought a LaserBee AX(a month ago)
Literally there was only 2-3% of difference when i've measured my lasers.
Costs? Under 20€ and few hours of work. No arduino,no any hard to get part.

Quote:

Originally Posted by epyn

Than i've bought a LaserBee AX(a month ago)
Literally there was only 2-3% of difference when i've measured my lasers.
Costs? Under 20€ and few hours of work. No arduino,no any hard to get part.

I agree that the Laserbee line of power meters are great for hobbyists. But they top out at 10 watts for the biggest version, and most of them are only good to 3 or 5 watts. That's normally enough for your average hobbyist, but if you have a CO2 laser or a high-powered YAG, you need something bigger.

The meter Ed is talking about will go up to 150 watts. And for something that can accurately read power that high, a $25 price point is really impressive. I was expecting 3 figures, minimum.

Adam

Hi Adam,

you can easily "tweak" a 5W sensor to measure powers up to some Kilowatts with expanded beam and aperture plates or better perforated grid sheets ;)

Viktor

Quote:

Originally Posted by sinfocomp

so far i was able to measure 10 watt laser acurately +- 5%
and 15 to 100watt + - 2%
resolution is .01 watt
sensing element is anodized aluminum and carbon black coating
convection cooled, might go higher power with forced air cooling
but my most powerfull laser is 150 watt

I see that you are using a Type 'K' Thermocouple for the power
sensing element.
For $25.00 I'll take one of your LPMs for testing right now...
You can PM me and let me know where to send the PP payment.

What is the 100% response time at 1 Watt ??

Jerry

I took the liberty of restoring the indentation of the arduino code and adding in English translations for some of the text (Mostly for my own benefit--in the immortal words of Korben Dallas, "I only speak two languages...").

The calorimetric approach is quite nice in its simplicity. :cool: Of course the mass of the heatsink has to be taken into the calibration, and using a heatsink means that measurement accuracy will be dependent on the surrounding air flow conditions. Measuring the equilibrium temperature and examining the slope during the measurement and cooldown periods would probably allow you to largely remove the heatsink and ambient characteristics from the measurements, but that would get complicated and mathy.

But with a known mass of known material with a known absorption you can get pretty close quite easily. Neat!

Code:

// Digital Laser Power Meter// v 2.1 #include <max6675.h> #include <LiquidCrystal.h> #include <Wire.h> //Max6675 CK,CS,SO MAX6675 thermocouple(4, 3, 2); int sense = 0; float cal = 0.0000; int t = 10; int tiempo = t; float p = 0.717; int m = 87; int maxt = 45; float temperatura = 0.000; float temperaturai = 0.000; float temperaturaf = 0.000; float temperaturaa = 0.000; float w = 0.000; //establecer conexiones LCD 16x2 // RS, E, D4, D5, D6, D7 LiquidCrystal lcd(8, 9, 10, 11, 12, 13); void setup() { Serial.begin(9600); // use Arduino pins FORMAX6675 VCC AND GND pinMode(5, OUTPUT); digitalWrite(5, HIGH); pinMode(6, OUTPUT); digitalWrite(6, LOW); pinMode(7, OUTPUT); digitalWrite(7, HIGH); lcd.begin(16, 2); sense = analogRead(A7); cal = sense * (2.0 / 1023.0); p = cal; // wait for MAX chip to stabilize delay(1000); lcd.clear(); lcd.setCursor(0, 0); lcd.print ("Medidor Potencia"); lcd.setCursor(0, 1); lcd.print (" Laser Co2"); delay(2500); lcd.clear(); lcd.setCursor(0, 0); lcd.print (" V 2.0 "); lcd.setCursor(0, 1); lcd.print ("521 229-419-3262"); delay(5000); lcd.clear(); lcd.setCursor(0, 0); lcd.print ("Cal P = "); lcd.print (p); delay (2500); } void loop() { //esperar temperqatura menor a tmax temperatura = thermocouple.readCelsius(); while (thermocouple.readCelsius() > maxt) { lcd.clear(); lcd.setCursor(0, 0); lcd.print (" Temperatura de "); // "High sensor temperature" lcd.setCursor(0, 1); lcd.print (" sensor alta"); delay(2000); lcd.clear(); lcd.setCursor(0, 0); lcd.print ("Porfavor Espere"); //"Please wait" lcd.setCursor(0, 1); lcd.print (" T = "); lcd.print (thermocouple.readCelsius()); lcd.print (" C"); delay(2000); } lcd.clear(); lcd.setCursor(0, 0); lcd.print(" Medir Potencia "); // "Measure power" lcd.setCursor(0, 2); lcd.print(" Encender Laser "); // "Turn on the laser" // guardar temperatura inicial temperaturai = thermocouple.readCelsius(); digitalWrite(7, LOW); //Serial.print ("Temperatura Inicial "); //Serial.println (temperaturai); //Serial.println ("Espera de laser"); delay (180); do { temperatura = thermocouple.readCelsius(); //Serial.println(temperatura); delay (180); //esperar a una diferencia de un grado de temperatura //wait for a difference of one degree of temperature if (temperatura < temperaturai) { temperaturai = temperatura; } } while (temperatura-temperaturai < 1); //Serial.println("Lecturas"); //esperar T segundos para absorber energia //wait T seconds to absorb energy do { lcd.clear(); lcd.setCursor(0, 0); lcd.print("ESPERE "); // "WAIT" lcd.print(tiempo); lcd.print("Seg"); // "Sec[onds]" tiempo=tiempo - 1; //Serial.println(thermocouple.readCelsius()); delay (1000); } while (tiempo > 0); //Serial.println("Esperando Maximo"); digitalWrite(7, HIGH); lcd.clear(); lcd.setCursor(0, 0); lcd.print("PROCESANDO"); // "PROCESSING" temperaturaf = thermocouple.readCelsius(); delay(180); do { temperatura = thermocouple.readCelsius(); //Serial.print (temperaturaf); //Serial.print (" - "); //Serial.println (temperatura); delay(200); if (temperaturaf < temperatura) { temperaturaf = temperatura; } } while ((temperaturaf - temperatura) < 0.75); w =((((m*(temperaturaf - temperaturai))*(4.18)*(p))/30)); //w = (((m*(deltat))/1000)*4180)/(t); //Serial.println("calculo"); //Serial.println(temperaturai); //Serial.println(temperaturaf); //Serial.print("Watts: "); //Serial.println(w); lcd.clear(); lcd.setCursor(0, 0); lcd.print ("POTENCIA LASER"); // "LASER POWER" lcd.setCursor (0, 2); lcd.print(w); lcd.print(" Watts"); delay(10000); tiempo = t; digitalWrite(7, HIGH); }

I would still like to know...
What is the 100% response time at 1 Watt ??

Jerry

Quote:

Originally Posted by lasersbee

I would still like to know...
What is the 100% response time at 1 Watt ??

The code sinfocomp shared shows that it waits for the the temperature of the heatsink (or really, integrating mass) to increase by one degree, and then after that has a fixed integration time of ten seconds. So the 1W response time will depend on the mass of the heatsink. Aluminum has a specific heat of 0.9 J/gK, so the addition 1 degree time is going to be about a second per gram. So clearly low power applications want a smaller integrating mass.

Quote:

Originally Posted by aberry

The code sinfocomp shared shows that it waits for the the temperature of the heatsink (or really, integrating mass) to increase by one degree, and then after that has a fixed integration time of ten seconds. So the 1W response time will depend on the mass of the heatsink. Aluminum has a specific heat of 0.9 J/gK, so the addition 1 degree time is going to be about a second per gram. So clearly low power applications want a smaller integrating mass.

Thanks for the additional Code timing info.

Quote:

Originally Posted by sinfocomp

Sorry, cant test, i dont have a 1 watt laser

No problem... Was just curious.

Jerry

Very well, but the device is already working, gives the necessary parameters?

Quote:

Originally Posted by sinfocomp

Hello, device is working good, gives consistent results.

Clearly, I myself design various radio devices from time to time, by the way, 3D prototype model, I will soon order aluminum casting