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Close up of the beam correction and combining optics.

My LPM is probably topping out here. It's based on an Ophir head powered by +- 12v

The drivers are mounted directly to the 1/4" aluminum base using mica insulators, so this makes a great heat sink.

Beam shot at 30% power.

The beam spot at 100' is about 4" in diameter, about 3.2mrad divergence.

To align the two beams I created a rig that at about 100' (30m) of length.

The output aperture.

Ok, I just noticed something interesting. The whine I'm hearing from the laser diode is not coming from the diode. It's coming from the block of wood I'm using as a beam dump. I moved my LPM into the beam and the whining stops. I would still love to know if this causes any more stress on the...

I just did. Narrow pulse width -- very sharp: Broader pulse width has a ton of noise: A 4.7uf filter capacitor helps the high frequency noise, but doesn't smooth the waveform or reduce the whine:

Hi -- I'm building a labby using a BlackBuck 8 driver and the new NUBM47 diodes from DTR. I want to control the power output and I'm experimenting with both an analog control voltage on the BlackBuck and using PWM from an Arduino. Using PWM would give me a lot more flexibility, but when the...

Thanks, LaserCo. I certainly spent enough time lurking on here before building or posting anything. This place is a wealth of information. It feels good to finally contribute.

Yes -- it still runs great. But I don't run it that often and when I do I don't push it. I think you're right about the stainless steel not conducting heat away from the heat sink. But it sure is pretty.

Ok. I just measured the current draw. With no input, the Ophir sensor draws 3.1ma on each rail, or 6ma total. The claim of 5ma sounds right on. I imagine it will go up slightly with a significant laser input and probably maxes at 5ma for each rail. The total draw for the circuit was only...

Good luck! I think Th3dArKn3o is right that this diode is a little much for the heat sink so do observe DTR's and Lazereer's duty cycle recommendation. A diode is a terrible thing to waste.

Good question, Jerry. The meter is only 3 1/2 digits. The range is selectable but I fixed at this range because it seemed more generally useful. A 4 1/2 digit meter would have been better.

These are excellent questions and if I was a good engineer I'd have answers for them, but I never measured the draw. My LPM is in my garage in my house, which is currently being remodeled, so getting to it is a challenge. I will try to get to it and measure currents on it this weekend and...

Ha. I spent extra on the cord -- it is a phone cord. You can spend days surfing the cable offerings on DigiKey. After browsing for far too long I came upon this and decided it was the one. It plugs in with an RJ45 jack too. I was a bit worried because it isn't shielded but it doesn't seem...

I got the head on ebay -- some company was selling them as surplus. I remember it was the only one for that price that didn't look like someone had run it over with a truck.

I will update the post tonight with the gerbers and/or .brd file and schematics. Total cost wasn't terribly cheap: you could buy a Laserbee for less, I think. I spent about $100 on parts, $50 on board manufacture and about $150 on the head. The digital volt meter was the most costly part and...