case positive 445

midias · Nov 5, 2010

After searching I have found my plan should be ok but I do not want to kill a 46 dollar diode so I am going to ask. Would it be ok to attach the case pin to the battery+ terminal on a flex drive and use a pointer pen as case positive similar to a new wish style 405?

Benm · Nov 5, 2010

It would not be a problem. The case is isolated from both power connections to the diode (i've measured this, > 2 MOhm). I'm not sure what the breakdown limit is for the voltage difference between die and case, but i'm quite sure it is much larger than any battery you plan to use.

udanis · Nov 5, 2010

One of my 445nm builds are case positive and it is working fine.

midias · Nov 5, 2010

Thanks guys I am planning on 2 AAA batteries so no problems there and I only plan on about 200-230ma of current. I am going to make a 445 pointer not a burner. I want something for work I can use in a crowded conference room.

Bionic-Badger · Nov 5, 2010

I don't think the 445nm diode even begins lasing until around 20-25mW output, which would make it beyond "safe" pointer-power levels. It may not be a "burner" but it will still be dangerous if anyone got flashed.

midias · Nov 5, 2010

Bionic-Badger said:
I don't think the 445nm diode even begins lasing until around 20-25mW output, which would make it beyond "safe" pointer-power levels. It may not be a "burner" but it will still be dangerous if anyone got flashed.

I have read they start around 7mw and I figure with a lens for the wrong AR I can do it. It will be a fun experiment. I am going by this

lasersbee said:
Well I finally found some time to build a 445nm Laser that I got
from EF... I installed the A130 into an Aixiz Module using a 405 G-1 lens.
It is mounted in a Z-Bolt clam shell heat sink..

I did a bit of testing and here are my results...
I tested in 100mW increments and stopped at 1300mW..
I used an Opto Power Corporation OPC-PS4005 Laser
Diode Driver.

Starts lasing @ 3.95V -- 7mW

050mW ---- 260mA
100mW ---- 310mA @ 4.09V
200mW ---- 380mA
300mW ---- 460mA
400mW ---- 540mA
500mW ---- 620mA @ 4.46V
600mW ---- 710mA
700mW ---- 800mA
800mW ---- 890mA
900mW ---- 980mA
1000mW -- 1090mA @ 4.79V
1100mW -- 1210mA
1200mW -- 1340mA
1300mW -- 1530mA @ 4.99V

For those of you that are trying to measure raw output
on a thermal sensor without a lens... your readings will
be skewed to a greater value...
The reason for this is because the 445nm LD's case gets
really hot and when you are very close to the sensor... the
head reads the LD's heat radiation on top of the Laser's
beam.. once you are a few inches away.. that effect is
negligible...

BTW... I found a 3/8" inside diameter rubber grommet that
serves as a lens ring adjustment method to not burn my
fingers.. It fits right over the knurled lens cap..
It's cheap and it works...

Jerry

Bionic-Badger · Nov 6, 2010

But that's just his diode. They vary a lot with some never producing that little light, or perhaps that light even ends up being below-threshold light. It also takes quite a bit of control to keep the laser at the correct power level. You'd want to have some feedback system to regulate it. You could reflect some of the light into a sensor to do it, but keeping it portable might be a pain. Good luck with it, but keep in mind your audience's eyes!

midias · Nov 6, 2010

Bionic-Badger said:
But that's just his diode. They vary a lot with some never producing that little light, or perhaps that light even ends up being below-threshold light. It also takes quite a bit of control to keep the laser at the correct power level. You'd want to have some feedback system to regulate it. You could reflect some of the light into a sensor to do it, but keeping it portable might be a pain. Good luck with it, but keep in mind your audience's eyes!

That is why I plan on using my lpm and testing a lot to make sure it does not mode hop or change output.

Blord · Nov 6, 2010

What laserpen are you using as host ? I was thinking about making a 445nm laserpen just for the color, not burning. Is it possible just swap the 405nm diode from the laserpen and replace it with the 445nm diode ?

midias · Nov 6, 2010

I am using a case I got off ebay. I will try to find a link

midias · Nov 7, 2010

Here it is I got the black one

http://cgi.ebay.com/Green-Laser-Poi...538?pt=LH_DefaultDomain_0&hash=item588abd3c12

Blord · Nov 16, 2010

And did you succeed building a 445nm low power laser ?
I want to know what the minimum current for a 445nm diode is to lase.

midias · Nov 16, 2010

Blord said:
And did you succeed building a 445nm low power laser ?
I want to know what the minimum current for a 445nm diode is to lase.

YES I did. The laser pen outputs approx 20mw cold and gets down to about 14mw warm.

Things I learned about the a140 with just the aizix head with no back it gets warm fast at ~200ma. While warm it changes mw fast.

The laser starts to lase very weakly at approx 185ma and changes color and brightness around 195 but warms quickly and goes dim again. I was able to get ~12mw cold but it quickly went dim.

For my setup I used a LM317 with a pot to allow 180 to 300ma adjustment. I put an inline current meter on the diode and adjusted the pot with the full aixiz module while watching a LPM. at ~208ma I found the sweet spot and dialed in a flexdrive for the same. I used a kit I bought off ebay and an old green driver board trimmed down with everything removed as a switch. The lens is an aixiz plastic standard lens. The beam reminds me a lot of a 15mw green.

Blord · Nov 16, 2010

200mA to just lase the diode ? Dang, pretty inefficient at low power.
I like the idea using a baby LM317 as driver, but isn't the voltage from 2 AAA batteries to low ? The LM317 needs 2V to operate by itself, leaving almost nothing left for the 445nm diode. Or are you using two 10440 3.6V in the pen ?

midias · Nov 16, 2010

Blord said:
200mA to just lase the diode ? Dang, pretty inefficient at low power.
I like the idea using a baby LM317 as driver, but isn't the voltage from 2 AAA batteries to low ? The LM317 needs 2V to operate by itself, leaving almost nothing left for the 445nm diode. Or are you using two 10440 3.6V in the pen ?

I am using 2 AAA batteries with a flex drive. I used a LM317 to dial in the current because the POT was easier to adjust. You could use a LM317 in a SOIC or TO-92 package with two 10440 batteries but I wanted to use standard batteries even if it cost me an extra 20 or so dollars.

Xer0 · Nov 16, 2010

Hey. i use the same host, but with the o-like 405nm boost Driver.
how did you manage to get the Aixiz back in? mine didn't fit.

Altough, my Pointer is way to bright, can even smoke black plastic focussed for some seconds, then it goes dimmer, while threshold rising

case positive 445

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