Want to power a 15 mW Blue Laser Diode with AAA batteries need help

[waldolandry]

Hosed the lasers circuit board trying to repair a disconnected part but was able to salvage the 3 prong laser diode and it should work fine. I am just wondering if I could just hook it up to a household "Battery Eliminator" (Fully adjustable from 3V - 12V. It was a Ray brand.. Ebay laser. Any way to do this without wrecking it, or spending any $ lol. Could I harvest the circuits from an old CDRW burner or DVDRW and just solder the diode onto that? Or is it just as simple as soldering my battery eliminator wires on there? Any help would be awesome, thanks guys. This site rocks by the way, very informative

 

[T_Warne]

I don't know what a battery eliminator is.

Take a look here for info on laser drivers
Drivers, Test-load, Power Supply, & Batteries - Laser Pointer Forums - Discuss Lasers & Laser Pointers

 

[waldolandry]

I also have a Green 5 mW laser 532nm. Wondering if my old school telescope view pieces would shrink the beam enough to burn at close range? I never use it so not worried about wrecking an eye piece. (Google Earth Pro, Moon, Mars, Stars.. All I need for astronomy.

 

[waldolandry]

It uses a wall outlet to convert power into 3V 6V "9V battery adapter" and 12V to universally power any small battery powered device. Used to have 4 attachments on it but now its just wired to a 12V cpu fan.

 

[waldolandry]

Replaces battery power with standard household current Simply plug the Battery Eliminator Universal AC/DC Adapter into a standard 110V power outlet, then into a battery-operated electronic item and have a constant power supply. You'll never have to buy batteries again, saving you time and money, and helping the earth out in the process.

 

[waldolandry]

Set to 3 volts of course . Or would my diode just pull all 3 volts and fry in 3 seconds? What kind of electronics can I harvest a resistor from?

 

[T_Warne]

Waldo,
It's not just the voltage that is important, it is the current. 3v @ 1A will definitely fry your diode. Do look around the "Drivers" section.

The best way to search the forum is to use the Google search bar at the very bottom of every page.

As to where you can find resistors... I suggest buying the correct value that you need from RadioShack or on line. Trying to find the right resistor off an old circuit board will be like searching for a needle in a haystack.

Also, you don't need to make a new post each time, especially if no one has responded yet. You can use the "edit" button at the bottom of you last post and add the new content there.

 

[conundrum]

A possible method is to use an MC34063 to generate the required constant voltage, then add an LM317 in series with the output to limit the current with a capacitor between MC34063 output and ground and a 10K resistor between LM317T output and ground.
This approach has triple redundancy so even if two of three systems fail the diode should survive.
Adding a thermistor across the bottom resistor of the "stack" also means it is immune to overheating as the output will decay gracefully.

The typical blue diode takes between 15 and 31mA to lase and this threshold current determines the safe output power.
A good way to test it is to project the expanded beam onto a white card sheet, and wear bluray blocking goggles.
At a level of current just below the "fail" aka COD point the beam will suddenly become less speckly as losses begin to rise in the cavity.

Note that the COD point changes with temperature and can be exceeded if light reflects back into the cavity.

I have also found from experience that the low power diodes are much more sensitive to ESD than the burner diodes due to the physically smaller cavity.
An effective remedy for this is to solder a 4k7 resistor across the diode pins but making sure to work on a grounded plate with a wrist strap and ensure that the solder and soldering iron tip are all connected to that via a 1M resistor or lower.
Place all components on the plate first before you start just in case.

If you don't feel comfortable with such a complex circuit send me your diode and host, I will build a suitable driver.
I will also draw a graph of Iin versus Pout versus Vin as well for other people who have the same diode.

-A
#include "sendmeyourfrieddiodes.h"