Any LED flashlight style (center positive) 16.8mm boost laser driver?

DrMario · Nov 15, 2018

I see, my bad. I meant to say either batteries.

And I think it's case neutral, but I will check with DMM before I attempt to solder the wires onto the diode.

paul1598419 · Nov 15, 2018

I don't think you can find out with a DMM. It is better to use the case pin as the anode and using a CV/CC supply try to see if you can get light with the cathode on the right when looking at the back of the diode with the case pin in the down position. You will only need ~50 mA to see if it is case positive or not. If not, then move the anode to the right and the cathode to the left.

DTR · Nov 15, 2018

I only stocked the case neutral ones. Avoided the others.

DrMario · Nov 16, 2018

Even if Gallium-Nitride diode itself doesn't show up, Zener diode could show up in DMM because 1.5 to 2 Volts zener point is kinda required for the laser diode in order to defend that from ESD. Not all Gallium-Nitride laser diodes have that Zener diode built-in though, I wonder if Sharp 505nm diode has one.

Nevertheless, I can't wait to get that laser done. I'd imagine that 505 - 510 nm laser is like that of "Go" green light on the LED traffic lights which is a nice Aqua green color.

paul1598419 · Nov 16, 2018

Can you read the micro-printed number around the diode's window? I have a list of these numbers and the pinout diagrams for each with the wavelength range I measured for each batch of them. It could save you time and uncertainty.

Some of the Sharp diodes have a photo-diode inside the case. Don't know about Zeners.

DrMario · Nov 20, 2018

I will look at the numbers at the business end of the aqua green laser (the exact name of the color for the curious would be turquoise), I will need to find a decent ring LED loupe so I can read the tiny laser marked numbers.

I got the 20mm laser diode heatsink (I accidentally got the wrong size - 3.8mm instead of 5.6mm but that's easily fixable so I am not worried) and the neat mint green Convoy S2+ LED flashlight host (will have to get the anti-reflective flashlight glass lens so it doesn't reflect back and interfere with the diode operation, and the switchmode boost driver with adjustable current settings so I can set it to 5mW). Gettin' there...

Why the flashlight lens in the laser? That's to keep the dirt out of the lens, of course. I found out the hard way that it's not easy to clean tiny lens, I have a laser with ugly beamshot but still usable, so now I am going for preventative method (flashlight lens).

paul1598419 · Nov 20, 2018

Let me know that number if/when you get it and I will give you the information I have on it. Good luck.

DrMario · Nov 21, 2018

Since I have had nothing to do, I decided to take out my LED magnifying lamp (the battery died so I had to use another flashlight so I could be wrong here), and as you asked, I wrote down the number on the diode: SB147EC91

It was certainly hard to see through the anti-static bag however I had to triple-check to make sure.

* EDITED: After a quick browsing, apparently what I have is a higher binned laser diode, right into the Emerald green wavelength, between 507 - 509 nanometers, I wouldn't be surprised if it's a 520nm diode, as 505nm diodes are considered prototypes for some reasons. Would have been nice if it was SB1573N91 but I will be fine with that higher binned diode as it will still look nice regardless.

DrMario · Nov 21, 2018

After reading a bit more on those ~500 - 510nm laser diodes, it have made me feel uneasy as they're apparently very easy to turn into fancy LEDs... If that happens, I would be pretty discouraged because DTR's 505nm diode supply have dried up (I don't know if he would plan on getting more of 'em), and possibly elsewhere. Too bad they're not VCSELs, as they're far more tougher than regular FP diodes.

Here's to hoping I don't LED that thing...

paul1598419 · Nov 21, 2018

That diode is case neutral and is closer to 510nm , but nowhere near 520nm. These Sharp diodes aren't that easy to damage as long as you don't drive them harder than 300 mA. I would use the Nano Boost driver set to 275 mA, since it is not case positive. I have used this driver with many of my Sharp diode builds. Good luck.

DrMario · Nov 21, 2018

That's a relief. And I am not planning on driving it past 200+ mA, just enough for it to light up at 5 - 10mW which is good enough for the general usage (I am just going to use it as a Lithium-ion battery powered laser pointer more for the novelty purpose of collecting very rare laser diode in this case).

I tried to fit nano in the LED pill in my blue laser, it didn't fit, so I am looking for one that fits in the pill in this laser.

* EDITED: I was initially hoping to score the round 16.8mm 50-225mA adjustable current X-Boost (item #062) from Flaminpyro, however it looks like he stopped selling the drivers. So I decided to create this thread more to try and find a new source of the driver to buy one for my laser.

paul1598419 · Nov 21, 2018

If you are truly wanting to limit the output to 10 mW, you will have to drive it at a lower current than 200 mA. At 275 mA, they put out more than 100 mW. And that is with an acrylic lens. These do lase at 50 mA. I'm not saying that is the threshold, but it might be close to your output requirements. I haven't tested these for power at such low levels, so it is more of an educated guess.

DrMario · Nov 21, 2018

What I did with my 520nm laser was to start at lasing threshold (which there's no laser speckle artifact in the light) then turn it up to the point the diode starts to lase which I then call it good. (However, I found out threshold to lasing power adjustment WON'T work with multimode blue laser, as it certainly will lase below threshold current, so it's a FYI for the others who may attempt that as it could be potentially dangerous, due to the property of the diode itself.)

I may do the same with Aqua green diode laser as long as potentiometer is sturdy.

paul1598419 · Nov 22, 2018

It is easier to do with a spectrometer. Before you reach threshold the light covers several nms in a small haystack waveform. Once you reach threshold it becomes a sharp peak. Multi-modes are more complicated as you will have a single mode lase before the others do.

DrMario · Nov 22, 2018

That's an interesting point, especially with the multimode laser diode lasing threshold.

Calibrated spectrometer would be nice to have, still very expensive even used off eBay. Very hard to DIY too, even with FPGA or some fancy software on the microcontroller.

paul1598419 · Nov 22, 2018

Yeah, I had wanted one years before I finally pulled the trigger and bought one. Eventually I want to get the Ocean Optics HR4000 as it has a more pixelated sensor, so it should be even more accurate across the wavelengths I am interested in. I have seen them for as much as $2,000.00, but I am always on the lookout for a good deal if it has the grating and slit I also need in it.

Any LED flashlight style (center positive) 16.8mm boost laser driver?

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