Green Laser Diode

Hello,

I recently purchased a green laser diode from eBay

Here is the listing (http://www.ebay.com/itm/High-Quality-532nm-50mW-Green-Laser-Diode-Module-DIY-for-Laser-Pointer-Torch-/121256201990?hash=item1c3b6ecf06:g:ZqsAAOSwyjBW76hr)

It says the operation voltage is 3v - 3.7v So today I plugged in my Arduino UNO ran a jumper between the 3.3v plug and the ground to the laser diode but the laser does not turn on. But if I run the same jumpers directly to an AA battery it turns on right away.

I am unsure why this is can someone help me

Thanks

The 3.3V output probably can’t supply the current. Have you got a voltmeter to check the 3.3V to see if it’s “holding up” when the laser module is connected?

Your “eBay style” specs don’t give you the current requirements.

3V3. A 3.3 volt supply generated by the on-board regulator. Maximum current draw is 50 mA.

This module looks very similar to yours and it shows that the potentiometer is used to limit the current from 0-580mA. Like DVDDoug said, you are probably overloading the 3.3V output capability.

Can you try turning the pot right down and testing again?

I would doubt that 50mW claim.

Those lasers are <5mW, though I suppose advertising that max is <50mW is still literally correct.

I can power a red laser diode with my Uno just fine, not sure how it’s working on a single AA, unless you mean two of them. Is it bright on the AA setup? Make sure you have it hooked up the right way in the Uno? Test the voltage on your Uno pin to see if it’s working?

Laser diodes must be supplied with constant current - constant voltage will either do nothing or probably blow them up. The current needs to be set close to the nominal current (too little, no lasing, too much, fried).

The simplest way to do this is to waste power and use a higher voltage (about twice the nominal) and a series resistor (a power resistor normally, it will dissipate as much as the diode).

The module in question appears (from the picture) to already have a regulator, but we don't know how much current it needs, but it'll be something around 0.2 to 0.5A I guess (laser diodes are less efficient than LEDs).

Its pretty clear that this is designed to be part of a torch using lithium batteries, so give it 3.7V I reckon - if you have a bench supply you can check its regulating the current.

Wear the right laser eye protection for that wavelength, and point it at something matt black (50mW can burn paper, note).

Oh yes, the other thing, it needs a heatsink.

What he got was a 'green laser pointer module', not a LASER diode. It is in all likelihood a DPSS module ( a KTP crystal, over a 'tuned cavity', pumped by a 50mW IR diode, driven by a constant current regulator/driver). The pump diode could even be more than 50mW of IR. Heatsinking is provided primarily by the brass module casing. It 'probably' requires 200mA, or more to drive the diode.

A BIG electrolytic cap across the module supply might help provide enough power to support slow pulsing,but not constant drive and will stress the 3V3 regulator on the arduino.

Eye protection note is a very, very, good point. BUT:: BE AWARE THAT THESE CHEAP DPSS MODULES ALSO PUMP OUT A LOT OF IR AND MOST ARE NOT FILTERED.

Hi,

Description OF PRODUCTS:

Wavelength:
532nm
Power output:
50mW with 5% tolerance
Threshold current::
260mA
Maximum current:
360mA
Requirements Voltage:
1.7~2.2V
Working Temperature:
+10dgC-+40dgC
Storage Temperature:
+10dgC-+50dgC
Lifepan (under normal operation)
>5000hours
Size:
12mmx35mm

Attention of Products:
Red cable at "+"
Black cable at "-"
It working must with Cooling Heatsink/ Heat Sink together;

The specs at the ebay site.
Tom… :slight_smile:

Hi,

I have to agree with most of the other posts that recommend careful drive for the laser diodes. Normally they have some type of feedback to control the current because it has to be more carefully controlled.

If we look around on the web we find circuits for this kind of thing that do have the feedback.

AI, It's a Laser Pointer module: cheap constant regulator feeding an I.R. pump diode, which shines into a cavity, with a KTP crystal (strategically placed so that the LASER Diode shines up a facet, to affect frequency doubling, thus creating a GREEN beam, as well as the I.R.), and most likely, no I.R. filtering. Cheap, inefficient, but functional, setup. No optical feedback (what you really refer to) needed and you certainly do not need any feedback concerns supplying it...

Now, if we were talking a REAL green semiconductor LASER diode, very expensive for the optical output, then we MIGHT want to consider the internal feedback diode (if, in fact there actually was one manufactured into the LASER).

Hi,

Oh, a ready made module should be better then. No fuss. I see a lot of people in forums wanting to drive raw laser diodes.