Build a laser show that moves to your favourite music

 by gmilburn
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This is a home laser show I built with a 35mW green lab laser. The laser bounces off a mirror attached to a speaker, then goes through a diffraction grating so the patterns will cover my entire ceiling. It's pretty sweet.

You'll need a green lab style laser module, a pair of old headphones, a box, a switch, an AC/DC adapter, and some hand tools.

Here's a link to more detailed instructions with a full parts list.

You can see some videos of it in action here and here.
 
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Step 1: Power Supply and Control

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The first thing we want to do is provide power to the laser itself, and provide any easy method to turn it on and off. The power is coming from the AC/DC adapter, but it ends in one of those plugs we're all so familiar with. What we need to do is wire a receptacle (which connects to our power adapter plug), to a switch (which allows us to turn power on and off), which then goes to the laser driver board itself.

Don't connect anything to the laser yet! Why? We need to mount the switch and the receptacle in the box, and you'll quickly find that you need to pass the wires through the little hole in order to mount the switch. The laser, needless to say, will have a bit of trouble fitting. Put everything into place, and apply glue to the inside to ensure everything stays put. You don't need to do this, but it doesn't really hurt.

Now we can solder those leads to the laser, and fix the laser driver board to a part of the box. If you look at the board there should be a big piece of metal attached to a component, that's the heatsink for the power transistor. Make sure it has lots of free space around it, it can get hot and needs to cool off.

Make sure the laser is pointing away from you at something non-reflective and cheap (a piece of wood is great), plug the AC/DC adapter in, and turn the switch on. You should see a whitish dot appear. Alright, now we have a working laser that we can easily turn on and off!
thepelton says: Apr 4, 2011. 2:13 PM
I remember watching a laser light show, and there is a way to make a cirlce with the light. You send the laser against a mirror that is angled, and on a rotating shaft so it wobbles in a circular fashion. Sending a laser light beam against it will give you a circle, or if you change the angle, an ellipse.
ALogan97 in reply to thepeltonAug 14, 2011. 10:37 AM
Yeah, I did that with my green laser by shining it off of an angled lego at the top of my eiffel tower statue. But it only made a parabola, not a full circle. It's very interesting to look at.
DrCoolSanta says: Jul 27, 2008. 7:38 AM
It could have been made easier. It is just a laser pointing towards a mirror attached to the speaker. Anyways the idea is great.
DYLEGO in reply to DrCoolSantaJan 15, 2009. 6:01 AM
DUDE!!! That is so cool! Too bad people in the US can't build it... They made it illegal to ship out lasers more than 5mW... Jerks. They always ruin my fun !
thepelton in reply to DYLEGOApr 4, 2011. 2:15 PM
If such lasers were illegal to own, my Epilog engraver would either be illegal, or nonfunctional.
gmilburn (author) in reply to thepeltonApr 4, 2011. 3:28 PM
It's a rather odd situation, seemingly limited to laser pointers and consumer level retail lasers. Here's a link:

http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/HomeBusinessandEntertainment/LaserProductsandInstruments/ucm116373.htm

"Does FDA have a mandatory limit on the power emitted by laser pointers?

Yes. Laser products promoted for pointing and demonstration purposes are limited to hazard Class IIIa by FDA regulation.
21 CFR 1040.11(b) and 1040.11(c), limit surveying, leveling, and alignment, and demonstration laser products to Class IIIa. This means that pointers are limited to 5 milliwatts output power in the visible wavelength range from 400 to 710 nanometers. There are also limits for any invisible wavelengths and for short pulses. Pointers may not exceed the accessible emission limits of CDRH Class IIIa or IEC1 Class 3R."
ALogan97 in reply to gmilburnAug 14, 2011. 10:31 AM
yes, but that just applies to lasers promoted for pointing or demonstration purposes. It says nothing about lasers *not* promoted for pointing or demonstrations. just buy one promoted for science, lab work, or disc reading and use that. Also, I've seen lasers for sale that are 20 to 1000mW available in the US... seems odd, are you sure that's right?
thetech101 in reply to DYLEGOJun 7, 2009. 6:03 PM
They changed that to 10 mW. And building your own is not illegal. You can make them out of very powerful LEDs if you know where to find the parts.
willrandship in reply to thetech101Apr 15, 2011. 7:42 PM
Or swipe one from a DVD burner. They're sometimes upwards of 100 mw
ALogan97 in reply to willrandshipAug 14, 2011. 10:34 AM
I would advise against that, only because those can be powerful enough to light matches, burn through cardboard short circuit street lamps, etc. But it should be safe if you diffuse it enough. I'm not a laser expert though, so I may be wrong.
willrandship in reply to ALogan97Aug 14, 2011. 3:44 PM
Well, yeah, that's what makes them fun!

But anyways, for this application you'd probably want to use a big lens, and spreqad out the signal. That way, you could get the brightness of a 10mw point on a much larger surface.
SniperInTheDarkness in reply to DYLEGOMay 18, 2009. 12:24 PM
then does that mean that dvd burners, hd-dvd players, blu-ray players, and laser cutters are all illegal here in the US?
coolfordy in reply to SniperInTheDarknessApr 18, 2011. 10:11 PM
no dvd/cd players and burners are in a different class to hand held pointers. and a good 8x dvd burner will have a laser diode around 250mw
DYLEGO in reply to DYLEGOJan 27, 2009. 8:30 PM
The one problem is that it won't be very loud... It could be modded with a larger speaker... Hmmm...
The nerdling in reply to DYLEGOJul 20, 2011. 4:57 PM
15'' sub wooffer would be really good for this with a huge amp and 32 speakers around the place turned up full blast.
that would be so cool
gmilburn (author) in reply to DYLEGOJan 28, 2009. 5:24 AM
DYLEGO - The internal speaker is just to create vibrations for the laser itself. It doesn't really make all that much sound. I use a splitter cable from my audio source - one cable goes to my speakers, the other to the laser show.
DYLEGO in reply to gmilburnJan 28, 2009. 6:33 AM
That makes sense... I guess I should read the instructable all the way through next time, huh? DYLEGO
the_burrito_master in reply to DYLEGOJan 27, 2009. 4:35 PM
I have a laser pointer that can shoot across my 2 acre long yard! it's a laser level so I guess it has to be powerful. Only thing is I cant get the true laser pointer out of the thing. It's a ft and a half long so I wouldn't be able to do much with it without taking out the laser.
DYLEGO in reply to the_burrito_masterJan 27, 2009. 8:28 PM
Maybe I could mod a normal laser pointer...
cr4zy5pacec0w80y in reply to DYLEGODec 9, 2009. 12:31 PM
you cant change red ones only green ones. the green ones are restricted, where the red ones are maxed out. google it.
SniperInTheDarkness in reply to DYLEGOMay 18, 2009. 12:22 PM
or just buy a 20x dvd burner or an obsolete hd-dvd player and use those lasers. there are more than a few instructables here that tell you how to harvest and use those lasers that are capable of 100+ mW. Both you can usually get for under $50. heh. heh.
Electorials says: Aug 1, 2011. 11:36 AM
It's so cool!
I like the idea :)
The nerdling says: Jul 20, 2011. 5:00 PM
when i get some lazorz and mirrors i will make a huge lightshow with the subwoofers i have
thepelton says: Apr 4, 2011. 2:17 PM
Just remember, do not look directly into the laser with your remaining functional eye.
cmai00 says: Jan 5, 2011. 5:57 PM
cool cool pretty nice good work can you make a video so I can see it in action thanks
alexrom17 says: Oct 18, 2009. 6:42 PM
Does it matter how big the headphone are?
gez in reply to alexrom17Nov 8, 2010. 9:37 AM
yeah it matters, but the dancing happens anyway, bigger speaker gives you bigger angle of move.
alexrom17 says: Oct 19, 2009. 7:22 PM
how much power does the AC/DC adapter provide?<br /> <div id="refHTML"> </div>
the_burrito_master says: Jan 27, 2009. 4:33 PM
Awesome! great instructable!
omnibot says: Dec 28, 2008. 5:04 AM
Nifty. I think we've all thought of this without ever doing it so well. Moar pichsus though!
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