680nm Deep red laser custom build

Hello to the folks of LPF!

I have been working somewhat silently on a new build....at 680nm!

These are NOS lab-grade diodes I've had sitting for a little while, and decided to make use of them. they're corrected, optionally monitored, and very good quality. (Diode is a 9mm PS031)

I've been waiting a while to do this due to lack of funds, but i decided recently "ah to hell with it" and started ordering stuff anyway. I ultimately decided on an LM1117 linear driver because i needed a huge dropout to get down to the necessary 2.5V or so @ around 90mA. this is tested to give 30mW and is the max suggested rating for it.

I'm using two 3.7V batteries to test it and driving it at around 108mA.

I have access to a few more, so if anyone wants one let me know...I'll happily make you a module :beer:
The pics don't really do it justice...its really a deep deep ruby color. Enjoy!

a peek inside...hello diode!


Bare module with driver showing


dot on the wall: (too bright for my camera to show it properly its actually very deep red)


Pic of the completed module in heat-sink:

Cool! Never heard of 680nm diodes to be honest. How does the color compare to 638? 650? is it really that much different?
2.5 volts at 90mA seems kinda weird for a diode-maybe I'm just used to high powered reds. This would make a nice addition to my collection, I may get one (theres a few on Fleabay currently).

Looking forward to seeing the completed build!

That is a nice build with the 9mm 680nm diode. I never heard of it too.
My closest laser to this wavelength is 685nm. The color is just deep red like the 660nm but weaker and less brilliant.

Yes it's a very subtle change. But you immediately can tell when diffusing it in something. It turns to a dark ruby lustre compared to a 660 which is more of an apple or fire-engine red. The ones on the fleabay are more expensive than mine for the same thing I think. I believe I paid 28 for individuals & bulk order was less. I think the eBay ones are 34 plus more in shipping, or a generic one was 25ish. They're really nice so I'm thinking of making more.

Are those trustfire batteries any good? How do they compare to ultrafires?

All the ones I've gotten so far are good. Overrated though tested at about 4300mAh not 5000. But they work good. Ultrafires aren't too bad as long as they're not fakes. But definitely I'd take panasonics over both if possible. I need some good 16340s

I may make a 680 pen eventually, I am finding that i like pen builds a lot. And Meredith sells them for slightly cheaper than they are on eBay.

Very true. I like these circulaser diodes. It's a pretty color. I like pens, but they struggle with high power because they get too hot