My violet laser build :D ;)

Ok guys, I've been having everybody tell me that TO220 case LM317's can't fit into a 1AA flashlight body, and yadda yadda. So I decided to take it all apart again to snap some pics in efforts to hopefully conclude the stream of emails and things.

This is a photo "how to" guide.

This circut enables the violet diode to actually get the power it needs, unlike all the 5 and 5.1v stuff that barely or doesn't meet threshold current.

The SMT cap is 1mfd, and its its filtering the output to the diode. The resistor is 100ohms, and it's also in parallel to serve as a minimum load on the LM 317 to set voltage to a safe point before adding the LD.

The tab on the TO220 case LM317 has been snipped off an filed a bit on the corners. The pot was a large one, but it also happens to be a very accurate and smooth pot for making tiny adjustments, and it all fit, so I used it rather than a smaller unit. It was originally going to just be to dial in the circut before replaceing with a smaller pot or a fixed SMT resistor combo, but since it all fit, this lets me retain smooth adjustablility.


Ok, here come the pics.

VERY nice ! Great work on that !!!

good job what kind of case is that, it is perfect

Its a dealextreme cheapy 1AA twisty.

Thanks for the postive feedback.

oh ok i may have to buy one , how is it fitting (what i think are) 2 cr123a's did you widen the tube or do they already fit?

They are R-CR2's, and they share a diameter with an AA battery, which this tube was bored to fit.

You need to get the type with no nubbin, as only 2 no-nubbin RCR2's stacked end to end matches the exact legnth of 1 AA cell. If you can only find the nubbin type, I've filed the nubbins off and the battery was not effected.

I bought them from lumenhound who is a sponsor of this forum. They shipped fast, prices were fair, I recomend them.

nice work indeed! what sort of current and voltage do you have the diode running at? I have mine at 21volts!!!!!!!!!!!!!!!!!!! (35mA).

Very nice job. I like it!!!

~6v @ 50mA

If I focus it, I can actually burn very thin black plastic with it. It's by no means a powerhouse, but it is adquately bright to use in meetings at work as my laser pointer.

do you find that the plastic lens in this kit is adequate for transmission of the violet wavelength with minimal loss? I have read elsewhere that plastic lenses may be problematic in this regard.

That laser lens is terrible. I know it's eating a large chunk of my light output because I can feel that lens get very hot, even if I have the heat from the diode roughly isolated.

When I use the same diode with the same power in this little cheapy brass case with glass optics, the laser looks at least twice as bright to my eyes (indication of 4x power).

My other violet laser uses that little brass case with the same driver setup inside the same flashlight body, but I epoxy potted the whole unit, and gave it to my mom to use as a tool when she gives presentations in meetings.

It was my 2.0 version (throughly waterproof and impact proof), and it improved fit and finish over this unit I showed the pics of above, but being potted, it isn't going to be very photo-friendly like version 1.0.

any chance for a schematic? I can't quite make out what's going where in those pics ^_^

LFP - your workbench seems to be an awfully like mine.....hehehehehehe !