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DIY LPM Pics and Vid

Wolfman29

Wolfman29

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I mean, it was with this laser power meter than I discovered that my 445 is a zombie, same with figuring out that my green was waaaay underspec, and that my 12x is pretty efficient, and that my reds are about average.
 





Jufran88

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Congrats on your DIY LPM! I'm still waiting for my PCBs to arrive, was suppose to arrive yesterday, but nothing came. Sad face.
 
Jufran88

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I did. I made my boards on EAGLE and had them fabricated at a board house. What's wrong with that?
 
Wolfman29

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No, I mean etch the boards yourself :p I did the same thing, printed out the reverse of my board with thick toner and a glossy surface, pressed it onto some copper clad, etched it, and drilled the holes! The REAL DIY way!
 
qumefox

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Eh. Photoresist is so much easier to deal with than the 'iron on toner' method. And doesn't really cost any more to get pretreated copper clad either.
 
Wolfman29

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I have thought of trying that, but I haven't found any good tutorials or sites displaying how to easily access photoresist boards or how to do it effectively, at home, etc.
 
Jufran88

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If you were to really DIY, you would have to make your own volt panel meter :p

But, I rather not etch the boards myself. Just my preference.
 
piferal

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Wolfman29 said:
I actually *have* tested a green and two reds and my 445nm blue. The green specced out to be about 137mW, which makes sense for a cheapy Rayfoss 200mW laser.

The red which was running at 380mA (Aixiz acrylic) was at around 150-175mW, the red running at 434mA (Aixiz acrylic) was around 200mW or so.

Overall, I think the paint I chose was a good choice - pretty accurate for all of those.

For the 445nm... I think the diode died (got a reading of 500mW at 900mA), but there was also some burning earlier and I think I damaged the diode (some emitters broke).

EDIT: And regarding calibration, there are two trimmers on the board and one trimmer on the voltmeter panel. The trimmer on the voltmeter panel, I'm pretty sure, is a calibration trimmer (for determining the ratio between input and display voltage), one trimmer on the board is for zeroing (setting the output voltage to zero when there is no input voltage) and another trimmer on the board for calibration as well. So I just played around with them until I got it to be semi-accurate.
Click to expand...

Thank you very much for your response ;)

Ahh ok, I wondered if you had calibrated comparing it with another LPM "PRO" yours, or of the other member, Or if you had used another means of comparison to calibrate it.

Certainly as it says Jerry, the specialist :tinfoil: , the sensor "TEC" should be out of the box to have more accurate readings, and not influenced by the heat generated by electronics, and also a better dissipation of heat generated by the laser in the sensor, when done reading.

As you say "and I am not *that* concerned about accuracy - just care about getting a basic idea"

I think this is an excellent job anyway :)

Congratulations again :beer:
 
qumefox

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I really need to get off my butt and dig out some of my op-amps and build one of these myself. I'm tired of looking at the 20W Ophir thermopile sitting on the shelf taunting me. heh. Ophir was nice enough to send me the datasheet on it and the curve is pretty flat over every wavelength i'd be testing, so I think a simple opamp voltage amplifier will be fine for making it useful.
 
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lasersbee

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qumefox said:
I really need to get off my butt and dig out some of my op-amps and build one of these myself. I'm tired of looking at the 20W Ophir thermopile sitting on the shelf taunting me. heh. Ophir was nice enough to send me the datasheet on it and the curve is pretty flat over every wavelength i'd be testing, so I think a simple opamp voltage amplifier will be fine for making it useful.
Click to expand...

Man.... what are you waiting for.....:D

Jerry
 
qumefox

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A 20W head isn't going to be very useful for much under 1W most likely. At least not using a simple op-amp amplifier. And very few of my builds have been over 1W.. I'm not really a MOAR POWER!!1! kind of person.. My favorite build currently is a little 60mW 445nm pen I built last week.
 
lasersbee

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qumefox said:
A 20W head isn't going to be very useful for much under 1W most likely. At least not using a simple op-amp amplifier. And very few of my builds have been over 1W.. I'm not really a MOAR POWER!!1! kind of person.. My favorite build currently is a little 60mW 445nm pen I built last week.
Click to expand...

You can easily use a 20Watt Thermal head to measure below 10mW...
Probably even down to 1mW...:beer:

Jerry
 
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