Help, my diodes will not emit light.

[Jwl456]

Ok. I am building a red laser from instructions I found online.

How to build a laser (general guide)

For my driver I am using: a 100 ohm potentiometer. 2 10 ohm resistors. A 1N4005 diode. A 10mf 16v capacitor. And a LM317 regulator.

For power supply I have 2 Trustfire 14500 900mAh 3.7V Li-ion batteries.

I also bought an Aixiz housing with a lens to pack my diode into.

For my diode I was going to use the red laser out of a 16x DVD burner but when taking it out, I broke it. So, I ordered a pack of new ones off of Ebay.

5mw laser diode 650nm 5 pack great for science projects | eBay

Now, yesterday I tried to connect my new diode(s) to my driver circuit. I hooked up the first one and got fairly dim, unfocused light. I turned down the resistance on the pot and it got brighter, but then got dimmer again. I think I may have burned it out. I never could quite get it to focus. I figured I had messed it up so I moved onto the next one. I soldered this one in as well but I didn't get anything from it. No light. Nothing. I tried both the third and fourth ones but got the same results. I recharged my batteries and got still nothing. I checked my circuit with an LED and it lights up just fine and I can control the brightness with the pot like I'm supposed to be able to.

What's gone wrong? Are my diodes the wrong ones? Or just crappy quality? Has something gone wrong with my driver circuit?

I have several pictures I have taken that I can post and upon request I can take as many more as needed.

Thank you in advance!!

 

[lasersbee]

It is obvious that you did not read all of the "instructable"
I'll let you figure it out with a little help.

1) Did you use the Test Load circuit to adjust your LM317
driver's current....:thinking:

2) What current do you think the LM317 drive puts out
at min and max of the Pot controlling the Driver...:thinking:

3) How much current is required to safely drive a 5mW Red
Laser...:thinking:


Jerry

 

[foulmist]

a 5mW red would only need around 10-25mA. It seems you fried all of them
CHECK THE Data in the photos of your ebay item - the current is there

get a test load
set the proper current
discharge the output caps on the driver (preferably with a resistor) or short them
solder a new diode
you turn the lens left or right to focus (but you need a live diode for that)

cheers :beer:
-Tom

 

[sinner]

Infact your problem was the 5mW diodes, You wasted your time on them imo..
You said you broke the 16x diode.. U soldered the components according to the guide i suppose, and that means ur driver is putting out 0~250mA according to the ddl circuit..
All u need is another 16x diode.. and a Preliminary Driver Output test which is done by using a "TEST LOAD" instead of a live diode..