Laser kit: Laser

[Jasper.tm]

Hey,
I've got 3.2V 5mW Laserpointer.
I also have an adapter. 3V, 300mA.

Can I use this adapter to power my laser?

And the adapter has one black wire, and another black wire with a white stripe in it. What is + and what one is - ?

Thx.

[Ocalon]

Okay so the laser will ideally supply 3 volts at 350 milli-amps of consumed current. The way the adaptor works is that the output voltage and current are dependent on each other: the less current used, the higher the supplied voltage will be and the more current used, the lower the supplied voltage would be.

Your best bet is to use another trimpot in parallel with the laser pointer so that any excess current will be drawn through the trimming potentiometer and won't overload (fry to a crisp) your laser pointer.

Check your laser pointer to see how much current it uses (it should be considerably less than 350 mA).

If you can wait a couple days, we'll put up an addition to the project page going through how to make a Laser module using a regular wall adaptor.

[Gogolak]

A short-hand guess would be that the white stripe corresponds to the positive (+) polarity and the other black wire is the negative (-).

[Doc Oc]

Right, and sadly there isn't any convention for labeling the polarity of adaptor leads so its really hard to say. Your best bet would be to just measure the voltage with a multimeter and mark which way the voltage polarity goes.

If you don't have a multimeter then we suggest going out an getting one (they're real cheap nowadays) and go a long way in helping measure voltage, currents, resistances etc. They're especially handy in debugging circuits and finding out what's going on with them.

If you don't already have one and plan to continue building electronics, you might as well get one now cause you'll definitely be needing one later on!

[Jasper.tm]

Oke, i'll take the adaptor to work and test it over there xD

I just want to connect the adaptor directly to the laserpointer, without circuitboards, restors etc...

[Gogolak]

then just use a +5V Fixed-Voltage Regulator 7805 from radio shack

[Ocalon]

Well you can try just hooking it up straight to the laser pointer but that would probably fry it (unless the current consumption of the laser pointer matches your adapter). But then again, you might get lucky and it just might work. Its a gamble.

Anyways, if you do decide to try hooking it up with some added components then here they are: (this is for a 5v regulator but you can get a 3.3v one)

1 x +5V Fixed-Voltage Regulator 7805
2 x 100 uF - 1000 uF Capacitors (some value within that range)

The "+" sign indicates that electrolytic capacitors are polarized: There is a positive and a negative terminal on an electrolytic capacitor (one of which will be marked). You need to make sure you get the polarity right when you install the capacitor.

[Jasper.tm]

Sorry for reacting so damn late.
I saw the video from Kipkay, the original idea i tried. I have exactly the same laser, and he uses a AC to DC 3.2V 500 MA adapter. So i think i can use my 300 ma adapter?

http://kipkay.com/videos/protect-your-home-with-lasers

Video, at 35 seconds you can see the details on the adapter.

Greetz,