How to power 3 Laser array

[Dzarren]

I'm trying to build a set-up for my university.
It will have a red , green and blue laser, "stacked" on top of each other.

So the dots will form a vertical "line" of three dots, each dot spaced maybe a half inch apart.

These three beams will pass through a double slit, or any other sort of diffraction medium, and the results will be visible.

I want to run all of these ~5mW lasers with a single power supply, with the ability to turn any of the three on or off with a switch.

I don't really know what I'm doing at all, other than my design. I have moderate understanding of circuit analysis but i am unsure where to start with the electronics. I have no issue building the hardware bits.

any input is greatly appreciated!

thanks!

Here's a crude picture of the basic set up.

The lasers will be able to be aligned by hand.

 

[diachi]

What laser modules are you using? Ideally you'd use three modules each with their own driver that all have the same input voltage and then just wire the drivers up in parallel to the correct power supply.

 

[Dzarren]

Ill be using the lasers that look like this.
I have all the lasers already, they all look identical, but with different color.

 

[ElectricPlasma]

^ What Diachi said.

But there are quite a few other factors you should decide on, e.g. for green, are you using direct diode or DPSS, what wavelength of blue, of red? Does it matter?

And depending on how precise your array needs to be, you're most likely going to have to get a black machined to get the beams parallel. If you end up using really low power laser modules, you can try mapping out a piece of wood and drilling as precisely as you can, but I'd say that's one of your main challenges, especially since they're vertically aligned in your design.

What kind of distance are we dealing with from the laser aperture to the double slit?

---Edit---

Ill be using the lasers that look like this.
I have all the lasers already, they all look identical, but with different color.

That looks like those chinese pointers, which are advertised as 5mW but in most cases a lot stronger. Must it be 5mW? If so, I believe someone else can step in for a source for some 5mW modules. I don't know any reliable ones.

 

[diachi]

Well, those should all have the same voltage requirements - they usually take 2x AA or 2x AAA batteries, so wiring them up in parallel to some 3V-3.2V voltage source should work. However - that's not what I would use for project as you'd need to use something like alligator clips to hook those up.

Something like these with proper leads attached that you can solder to your power source would be better: Mini RGB Laser Kit with Power Supplies and Optics | eBay

Blue module there is 5V, the others are 3.2V. You could use a 5V power supply and an LM317 configured as a voltage regulator set at 3.2V to power those. 5V hooked directly up to the blue module and LM317, LM317 hooked up to the other two modules in parallel. Or replace the LM317 with some other 3.2V power source.

Actually ... an old ATX power supply from a computer would probably work just fine as a power supply, they have a 5V and 3.3V rail. Or something else that has both a 5V and 3.3V rail would work fine.

The modules in that link come with a set of dichroic mirrors for combining the three beams into one - you may want to message the seller and see if they can offer the bundle without the dichroic mirrors to make it cheaper.

 

[Dzarren]

I already have all the lasers.
The "blue" is 405nm, the green is 532nm (i think), and the red is 650nm. pretty standard stuffs.

The green laser was cheap, so im guessing it is DPSS

The aim of the laser's will be able t be adjusted, since i want the system to be "modular" in the sense that different slit apparati can be swapped in and out.
I'm not worried about the aiming bit, I have a part designed that will allow the beams to be easily aimed precisely.
There will probably be about 6 inches from the diode to the slit configuration.

Yes, all the lasers run off 2 AAA batteries, so 3 volts. I dont mind using alligator clips too much, I should be able to make it permanent if i need to, since i have already bought all the lasers.




Can anyone show me a quick diagram on where the switches should lie in the circuit if i need to be able to turn them on and off independently, without adjusting the power supply?
So all in parallel, and I've got three toggle switches.
thanks all!

 

[SyKo]

If safety will be a major concern, as pointed out earlier you should be on the lookout for Modules/Pointers marked as 'APC' and for the green(532nm) module you'll want one with an IR filter.

Automatic power control (APC) means that the output of the laser will be properly regulated to its specified output, especially in the case of a 532nm DPSS which is very sensitive to things like temperature an APC module will yield a somewhat more stable output and will keep the output in the very least close to what was specified.

Look up Sams laser FAQ its quite a bland site but is full of information.

 

[Rivem]

I already have all the lasers.
The "blue" is 405nm, the green is 532nm (i think), and the red is 650nm. pretty standard stuffs.

The green laser was cheap, so im guessing it is DPSS

The aim of the laser's will be able t be adjusted, since i want the system to be "modular" in the sense that different slit apparati can be swapped in and out.
I'm not worried about the aiming bit, I have a part designed that will allow the beams to be easily aimed precisely.
There will probably be about 6 inches from the diode to the slit configuration.

Yes, all the lasers run off 2 AAA batteries, so 3 volts. I dont mind using alligator clips too much, I should be able to make it permanent if i need to, since i have already bought all the lasers.




Can anyone show me a quick diagram on where the switches should lie in the circuit if i need to be able to turn them on and off independently, without adjusting the power supply?
So all in parallel, and I've got three toggle switches.
thanks all!

If you're going to do this, put each switch to interrupt the lead you attach to the spring of each laser. Connect the leads together after the switches. This would be your common negative.

Connect leads from the cases together as well. This will be your common positive.

Just be careful of reflections since these are all typically way overpowered and can damage eyesight with strong reflections or direct beam hits. Most safety glasses won't cover all three (two IR as well) wavelengths at once either.