What is this kind of laser?

[mint]

Hello everyone,
I just buy a very cheap laser pointer and take apart it today.
When I expect to get a laser diode,
a little chip comes out.:can:

From left,
a copper cylinder,
a chip which emits red light,
converging lens,
screw cap of the lens.

Do anyone know what is the name of the chip and its details?
Thanks.

 

[ElektroFreak]

That chip is a very cheap laser diode. It contains a bare diode chip mounted to that little flat board. Pretty much useless for hobbyist purposes.

 

[mint]

Oh thanks!!
Actually it really not like a "diode" that I've even seen.

I am a wargame player, and I want to mount a laser pointer on my gun,
but I cant found any class 1 laser on street.
So I want to lower the power of these cheap things so that I wont hurt any others eyes.

One more thing I want to ask.
What is the operating voltage are these laser diodes?
I cant search any data of them in the internet.
Thanks again

 

[ElektroFreak]

I would guess around 2V for that diode.. you should check ebay for 1mW laser, although 5mW red laser will not be at all dangerous. In order for a 5mW red laser to damage someone's eyes it would have to be held steady into the eye for a matter of several seconds. That's very unlikely to happen accidentally.

 

[mint]

Thank you so much.
So I am going to start my experiment now

 

[rog8811]

There is usually a surface mount limiting resistor (small black plastic block soldered at both ends) on the pcb, behind the LD chip, if you solder a higher resistance one to the board you can limit the output.

Regards rog8811

 

[mint]

Yup, there is one.
And I'm going to put a 100om for limiting the strongest current and one 100om variable resistor for tuning the intensity to suit different enviroment.

I wonder why such device required three 1.5V batteries but not two.
I have tried to use one CR123A to drive it, and it works.
So what is the need of the extra 1.5V

 

[JLSE]

If there is someone close to you that has a power meter, you may want to test the final product prior to employing it.

I bought a kit not so long ago that had the same layout, cheap dollar store type pointer with it, that to my surprise produced 11mW of red without any modification.

Just like anything low budget, these lasers arent always what they say for output, and may not be safe for your project. Double checking may be a good idea here.

 

[ElektroFreak]

^An excellent point.

Off topic, but am I to assume you recently became a father, wannaburn?

 

[mint]

11mW really danger:cryyy:
but i still cant find any class 1 on sale,
maybe that is really useless:angel:

excluding the power meter,
is there any way to know how powerful is a laser?
just like calculating or something else?

 

[ElektroFreak]

^Nah, the only way to be sure is to use a meter.. but truthfully, any red 5mW pointer will not be very dangerous even if it is slightly over spec.. I wouldn't sweat it much. Your average laser sight is nothing more than a "5mW" red laser. Just make a habit of avoiding eyeballs when you use it.

 

[rog8811]

If you are puting a pot on it just wind it up until you get the brightness you need for your purpose and stop there, it is not going to be that dangerous unless stared into at close range.

Regards rog8811

 

[mint]

Affirmative

A funny thing that when I'm playing with it and my surefire.
I shot the laser to glass and some light reflect to my eye, the feel just like looking to a small light bulb, nothing hurt.
But the same thing happen with my surefire, I just feel pain and there is a black area appear for short time:angel: