Simple Laser Power Meter Using IR Thermometer

I am liking mine. I only wish we had more comparison results from those with more profesional LPMs.

Hey Glenn, I will send you mine if you are willing and have time to do some comparison tests. I think it will ship ok with the way I constructed it.

-SightFX

Yeah... I like the air shield around it...
You did a nice job on that..

Jerry

You can contact us at any time on our Website: J.BAUER Electronics

Ok guys does this really work? I am planning to start a project one of the following days. Thanks.

Do you think all the members who built one are lying...:thinking:

Just follow (exactly) the building procedures...dimensions
and materials used... and you will have a functioning....
Simple IR Thermometer Laser Power Meter.

Jerry

You can contact us at any time on our Website: J.BAUER Electronics

lasersbee said:

Do you think all the members who built one are lying...:thinking:

Just follow (exactly) the building procedures...dimensions
and materials used... and you will have a functioning....
Simple IR Thermometer Laser Power Meter.

Jerry

Click to expand...

I 'll just give it a try. What will I lose anyway? for less than 20 euro...

is the black thing that uses painted alouminium foil?

Great! I have the radio shack, type. I'll have to try this.

I cant believe I found this thread. I've been searching for days for something like this, with no luck. I was even going to start a new thread for "Dirty" ways to ballpark output without a power meter using benchmarks and such, then one miracle happened. Completely by accident, I was doing a search for how to turn on HTML for the posts (still no idea), and on page 3, this popped up.:bowdown:

A while back I got a "100mw" green laser through Amazon for like $40. I knew from the reviews that it was likely not going to be that high, but for $40 I figured it was still more powerful than my 5mW, WTF. Its a lot brighter and more coherent (almost no scatter), but it will barely weld two layers of black garbage bag together. Needless to say it aint no 100mW.:gun: (the label says <100mW class IIIa?)
I've been on temporary disability (back injury) for about a month and have spent most of it in front of my computer rekindling my decades long fascination with lasers. After a lot of research, and the realization that I can't import IIIb lasers, I decided to build one. I'm getting a Jayrob Side button kit @ 190mA (tomorrow!) and a "250mW" rated Blu-Ray diode module of unknown origin.
This leaves me with two lasers of unknown power. If I were building them to sell I would want as accurate a measure as possible, as it is it's really just about curiosity and having a number to tell people when I show it to them. I would think for most users $200+ is way too much to satisfy that desire, but $20 to find out +/-7.5% is perfectly acceptable. In fact I'm hitting the hardware store this weekend, and right after I build my new laser, I'm building one of these.
I was terribly disappointed to see that Warske left. I Was hoping to thank him for the post and maybe get more input and/or clarifications. It's ashame he didn't feel appreciated enough to override one persons harrassment of him. I for one appreciate him, and I wish him well.:thanks:

Oh, for those in Europe I found this:
DealExtreme: $24.74 Mini Digital InfraRed Thermometer with Laser Sight (-50'~260'C/-58'F~500'F)
They had a couple of others for less than $30 US.

Sorry I've been so verbose. This is only my 2nd post (after thanking Jay for my new kit). I guess I had a lot to say.

Happy Lasing

P.S. I think this should be a sticky too.

I did see those on dealextreme, but I highly doubt Dealextreme is the best source for precision tools xD

Hallucynogenyc said:

I did see those on dealextreme, but I highly doubt Dealextreme is the best source for precision tools xD

Click to expand...

I just had been reading in the posts, that either they were too expensive or couldn't get them delivered to wherever, so I posted the link. I figured since I can get one for half that at the hardware store, and how inexpensive (read cheap) DX usually is, that the accuracy should be good enough for our purposes.:undecided:

Later.

The accuracy of the IR thermometers is quite easy to test though.. measure a pot of melting ice for exact zero, and a pot of boiling water for roughly 100. The latter can be done more precise if you have a barometer to determine what the boiling point should be.

I had a gift card to my local fishing store, and they had a $40 IR thermometer, it looks like a piece of crap (plastic, runs on button batteries, really small) and it seems to take readings within about 10%. I'll build this later on...

Ok- with a quick and dirty setup (15 minutes tops) I consistently clock my "200mW" waterproof o-like at less than 140mW, with any focus or distance.. I just hope my "LPM" measures low. I am using satin finish, and my tinfoil square is held up by metal pliers... and my thermometer sucks.. oh well, guess i'll have to wait for a real LPM
ALSO: My "3.6V" 18650s are hovering around 3.7V, is this low for them? When I first measured them (after using the laser a while) they were like 3.9, and the charger is 4.2V also.

Yeah that is low, fully charged 3.6V are 4.2 V but I don't think your dilda would only be 140mW just becuase of the voltage drop. It could be, maybe buy another pair of batteries?

When you measure the power of a laser with this method, are you supposed to focus the laser to "burning strength" or do you leave it focused to infinity?

lazer said:

When you measure the power of a laser with this method, are you supposed to focus the laser to "burning strength" or do you leave it focused to infinity?

Click to expand...

don't focus it, that will just burn off the finish. As long as the dot stays near the center of the tinfoil and does not leak over, the readings should be the same.