DIY Laser Power Meter Interface Module

knimrod said:

I've updated the third post in this thread with the group buy details and status.

Archane and Jake21: I did not add you yet because I wanted to make sure you understand that this group buy is only for the interface module kit and not the DIY Amp. If you still want in on the interface module kit, let me know.

Click to expand...

w000t lets get'er done!

Yeah i'm still in for this. if I can't get the other board from the other post i'll just make my own. I could just make both myself but you've done the work so I figured I would chip in here.

I'm still down for this one, i'll check the other thread for the DIY amp board.

Archane, I have you down for one. Only 3 more to go before this group buy is complete.

Anyone else? Only $25. per interface kit.

Is it still possible to get on the second group buy?

PM sent down for one please......

Got you both on the list. Only one more to go!

Okay.. I have 9 kit orders..

If you're on the list, watch your PMs for instructions. Thanks.

paid

Paid for 1, Thanks soo much Knimrod ;D
Dark Horse

Hey Everybody.  IT LIVES!!!!!

I just finished my DIY LPM and Interface Module.  The pc reads within 1-2 mw of the dpm on the lpm.  THANKS KNIMROD.
One question, and if I overlooked it, I'm sorry.  Under the interface module software under the config section, what should I set the gain to for channel 1?  It defaults to 0.964mW.  I set channel 2 to 0mW to disable it.

And just so everyone knows how accurate this DIY project is, it reads within a couple mW of my Scientech 365 LPM.

Will try to get some pics up later.  Gotta play now!!!

;D :

Awesome!!!

I set the default gain to .964 because that's what it took to get my PC display to read exactly the same as the DPM. The gain reflects the transfer function of the 10-bit AD conversion (1000/1024) and the slight error with the op-amp gain (5.00/5.02). You may need to tweak it some but it will remember your setting.

The gain setting is not in mW BTW.. It's just the number that's used to multiply the raw A/D with to get the calibrated reading. The "units" setting in the config dialog sets the display units to whatever you want.. In this case it's "mW" for laser power. If you were using channel 2 to monitor current, You would set the units for channel 2 to "mA".

Please let me know if you encounter any weirdness or bugs. The next version I upload will have a print feature for the graphs.

SWEET. A print function of the graphs will be awesome!

How hard would it be to implement a USB sdk kit into the output to the P/C at this point? I have couple of them here and it seems this would be a nice feature for laptop use. This is a very nice kit and I can't wait to get it up and running. Thanks again!!!

I'm still waiting for a couple of payments.. I can't order parts and PCBs until I receive all the funds. Please let me know if you're no longer interested. Thanx.

I made my amp/meter and interface last week, but haven't tested the PC side yet - had to deal with a failed power supply on the PC! So this is not a report on that unit, though I'll get around to it soon...

But I wanted to plug this thought in before everybody gets theirs made:

I know people often ask where to get metal project boxes... and I found an excellent source for free!


Having paid $27 or so for red burner laser diodes, I decided to use the boxes they came in - that is, the DVD burner housing! It's nearly perfect - roomy but compact, strong, stable... and if I wanted, it could be mounted in my computer (and use its power).

The front panel of the DVD unit is easily modified, being just ABS plastic. It was fairly simple to cut out holes for the dpm, coax connector, and gain adjustment; and a slot under the dpm for the zeroing pot - a slide unit. The PC interface connector and the AC power jack are mounted on the back.

I decided to go with plug-in power, not liking batteries for essentially stationary equipment. So there's a small transformer (from a wall-wart) with a very simple circuit to make the split-rail supply. The jack is from my dead PC supply, so it takes the standard computer-equipment line cords.

By the way, there is a lot of good stuff in that DVD unit! makes the LD a real bargain with all those 'free' extras.

I'll post pics later... it isn't pretty though, I just kind of roughed it out - but I have a few more dvd housings to make a final version ;-)

I wish the others would get along with the program......I am excited and would like to work with this project !