Tried LM317T + 10ohm res + PHR-805T, shouldn't it be brighter?

See the photos

Please excuse the messy soldering

Powered by 2 cr123a's, this should be giving me 125mA right?

Like...80-90mW?

This is like 5-10mW maybe..

What went wrong? Any ideas?

Thanks

well first a lm317 has a big DO a lm117 would work much better also you must remember 405 is near UV and is not very visible compared to 660, 445 etc

It looks alright to me. 405nm diode isn't very bright, not even at 300mA.
Try if it light a match of pop a balloon. At 80-90mW it shouldn't be a problem.

Yeah I know it's not going to be really bright. I tried balloon and matches and nothing...so I am sure it is way less...

There is no heat produced by it.

What else do you think ?

Did you focus it to a point ? And always use a testload to measure the current output before any LD attach to it. Just make sure that the current is 125mA.

freeloader700 said:

Yeah I know it's not going to be really bright. I tried balloon and matches and nothing...so I am sure it is way less...

There is no heat produced by it.

What else do you think ?

Click to expand...

do you have a 9v battery around?

I can get one. Should I try that?

ya i don't think your supplying enough voltage because you are using a lm317....

Yea, to power it you need at least 9V.

Hmm ok...that sucks... That mean I'll have to change the setup. What if I was to use A different resistor...think that could work?

freeloader700 said:

Hmm ok...that sucks... That mean I'll have to change the setup. What if I was to use A different resistor...think that could work?

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Changing the resistor won't work to reduce the voltage requirements of the laser. Your laser diode requires a certain amount of voltage in order to function, as does your LM317. You need a resistor in order to set the current, so you can't drop that either unfortunately. The solution is to use more batteries in series for more voltage, use a different IC (i.e. lm1117, lm1085, etc..)for your driver, or use a different driver all together (boost driver).

Your CR123A Cells are they 3.0v,3.2v or 3.6v/3.7v.????

If they are not 3.6v/3.7v then its not enough voltage.

2 @ 3.6v

Remember, the IC has a large dropout voltage, the resistors drop around 1.25 volts and Bly ray diodes have a higher Vf then 445's or 660's

So, try connecting it to a 9v or a 12v ac/dc converter .

It Should be working then.

What i do notice though is in your picture you have the LM317 Heatsinked to the Metal Pill. Are you sure that the metal back of the LM317 is not shorting on the pill.? Did you make sure to put enough Thermal Adhesive to insulate it from the pill but at the same time have heat transfer With out it shorting. If it did short then you most likely damaged the diode.

Did you hook it up to a testload before you connected the diode.? This is one of the main test to do to make sure that there is no flaw's in the Design.

What also could be possible is the Diode was already damaged and came like that.

Also is this your first 405nm laser.? The Reason I ask is ~100mW of 405nm is Not that bright but you will be able to light a match and pop a balloon with it. Have you tried this.?

What I would do at this point is Not Turn the laser on anymore and hope the diode is not Zombied.

If you dont have a testload which iam guessing you dont either buy or build a testload and test the currant and see if everything is hooked up correctly.

Then After you rule that out and it indeed is running correctly then you must of received a bad diode or damaged somewhere down the line of building the laser.

So check and see what the currant is at with a testload and Let me know.

lazeerer said:

It Should be working then.

What i do notice though is in your picture you have the LM317 Heatsinked to the Metal Pill. Are you sure that the metal back of the LM317 is not shorting on the pill.?

Click to expand...

I agree with lazeerer. It seems that the lm317 pins are touching the heatsink. I'm not any expert, it was just a guess.

Any way, I'm curious about your situation.. I'll be waiting for news