Geoff hasn’t put instructions for this up yet, but I have some shots of the new version of the laser show…
Well, a concept is all very well and good, but if the parts are unaffordable or unavailable it isn’t going to be much good. It took me a little while to find some good places to buy from, and here’s what I found out.
I wanted a powerful laser, but it had to be able to run for a few hours at a time. A laser light show isn’t a laser light show if you have to shut it off after the first song – well, I suppose it is, but it’s a bit annoying if you’re trying to make a night of it.
A small green lab laser module fits the bill. Green is far more visible than red while still being affordable, unlike horribly expensive blue lasers. You need a lab module, or at least some form of heatsink – laser pointers, especially at the price point we’re looking at, will build up far too much heat in extended operation. This is the biggest expenditure in the project, and one you should take a bit of time looking for.
After much deliberation, I settled on a 35mW unit from DealExtreme. If you like my idea and instructions, please buy your laser through that link – it doesn’t cost you anything extra, makes sure you get the right part, and gives me a tiny bit of commission so I can keep building cool projects. The classic tradeoff of cheap, fast, and good – choose two comes into play here. This DX unit received pretty good reviews, and the price is right at ~$60. Just don’t expect the included free shipping to be lightning fast (they’re based in Hong Kong) and you’ll be alright. It took me a little over 2 weeks to get mine in Canada.
It throws an incredibly bright tiny beam and doesn’t heat up easily, perfect for our show.
Power Supply and Housing
Now that we’ve figured out what laser unit we’re using, we need to get a power supply and place to put everything. I went to Jameco, because it had amazing selection while still being accessible to the individual consumer – all part numbers specified are from them. I bought a regulated 6V 500 mA AC/DC adapter (#283573), which means that it has circuitry that ensures it always supplies 6V, unlike cheaper units. The laser itself draws ~ 380 mA, so I rounded up a bit to be safe. I also got a switch to turn everything on and off (#316111, I recommend getting a DPDT switch), a connector to plug the AC/DC adapter in (#281851, make sure it matches your adapter), and a nice plastic box (#675542) to hold it all.
This is where the magic happens, and what our whole show relies on. Make sure these stay clean and scratch-free. We need:
- a small circular mirror. I’d suggest a ~1cm (roughly 3/8″) mirror. Better mirrors will reflect more light more cleanly, keep in mind. There’s something called a “front surface mirror” that is ideal, but don’t worry too much if you can only get a regular one.
- a diffraction grating. I bought a high quality glass one (specifically the “transmission matrix” model from Dragon Lasers). You can also get sheets of holographic diffraction grating film, I suggest the double axis film from rainbowsymphony.com. If you’re Canadian like me, the easiest option in terms of shipping is the Dragon Lasers grating. It’s a bit odd since they’re in China and rainbowsympony is in the US, but I don’t set the shipping rates. Please post in comments if you find an international source of diffraction grating film sheets at a vaguely reasonable price.
Grab an old pair of big headphones, we’re going to use the speaker and cable from it. The bigger and louder the better – this generally means the speaker will move more, generating bigger patterns. You want the big ones that go completely over your ears, anything smaller will just cause the laser to vibrate a tiny bit and not really make any interesting patterns, unless you’re after a Star Trek meets caffeine overdose effect.
I found a good (albeit gaudy) pair at Radio Shack on sale for $14, which had the added bonus of coming with flashing lights that lit up to the music. Perfect!
You’re also going to need some other basic materials:
- a soldering iron, solder, electrical tape, and wire are a necessity. If you don’t know how to solder, don’t worry – just grab an old broken piece of electronics (the older and simpler the better since the parts will be spaced out more and easier to learn on), check out a soldering guide like this one, and practice removing and resoldering components. There’s no shame in spending a while on this and playing around until you’re confident – after all, if you’re like me, you only ordered one laser!
- a glue gun helps to keep everything organized and in place. Just be careful to not get glue everywhere!
- some balsa wood or popsicle sticks to mount the speaker and align the height of the the laser to match up with the speaker
- a Dremel tool is useful to drill the odd hole or two in your box. An old soldering iron will do in a pinch if you’re using a plastic box like I was, have steady hands, and don’t value your lungs too much (or ventilate appropriate)
- miscellaneous screwdrivers and hand tools always help (especially for taking apart the headphones)
Got all the parts? On to assembly!
|Note: instructions for an even-more-ultimate laser show are coming soon, in the meantime check out a sneak peek of it in action.|
This is probably the coolest thing I’ve ever made. It’s quite a step up from the Five Dollar Laser Show I posted a bit back. The only logical step after building that was to drastically increase the power and number of beams. I loved the effect that it generated, but it wasn’t bright enough, and only covered a small portion of the wall.
This my first attempt at solving those two issues, I think it worked out pretty well. Here’s the new version in action on the ceiling of my living room.
It’s quite an effect, and rather hypnotizing – it’s quite easy to zone out and become completely absorbed in the music. The multiple vibrating beams coming out of the unit also look amazing when fog or smoke is in the room.
Even the most ADHD-addled individual, myself included, tends to go “whoa”. You can also do cool things like hooking it up to a microphone and watching the patterns your voice makes. A disco ball or mirrors stuck to the ceiling help spread the effect around even more.
So how does one go about making one of these things? Well, I made every effort to make construction as simple as possible for two reasons. One, electrical engineering is far from my speciality and I didn’t want to kill myself/ruin a laser I could only afford one of. Two, I always hated seeing incredibly awesome projects on the internet that I never had any hope of building due to funds and bizarre parts. That’s not to say you don’t need some basic soldering and construction skills, as well as a healthy respect for the power of laser light, but it’s definitely doable if you put your mind to it.
The full details are in the links below, but what you basically need are a heatsinked lab style laser (so it can run for a few hours, high power laser pointers will get too hot), a diffraction grating, a pair of old headphones, and a few electrical parts to tie it all together.
So if you’re the type who enjoys projects, I strongly recommend giving this a shout – it’s proof positive that you can obtain amazing results without the backing of a large electronics company. If you do end up building one, please send me a link to the results so I can see how it turns out!
Laser safety is serious business.
No no, not in the internet meme sense, but blind you forever with no way ever to fix it serious.
I know I’m about to rant, but I’ll do it anyways. This applies double for any girl/boy geniuses working with lasers. I know that you’re going to play with lasers regardless of warning if you really want to (you are a genius after all), and you’re already discounting my warnings because you’ve been warned about child molesters that are going to kidnap you on the way to school, secondhand pot smoke that will make you kill your friends, and terrorists that are a color code away from murdering your entire family. None of that has happened, and so you rightfully assume that most adults are full of shit.
I don’t want to be buried in that noise. You are warned about a ton of useless crap that will never happen and is designed to scare and control you. This isn’t one of those things.
If you turn on the laser I used and your eye happens to be in front of it, and you realize it, blink instantly, and look away, your eye is still ruined. Your brain cannot react fast enough – and the laser will cheerfully burn through your retina. This isn’t something that medicine will be able to fix. You will be blind or see a giant black spot in your vision for the rest of your life.
I don’t want to tell anyone not to build this – it’s an awesome project. Like most things that are truly interesting in life, there is an element of danger. If you are sensible, calm, and use the resources available to you and act in an intelligent manner, you will be perfectly safe. So what do you need to do?
BUY GOOD LASER SAFETY GOGGLES, AND WEAR THEM EVERY SECOND YOU ARE WORKING ON THIS PROJECT. Once you finish the project, close the case, and screw it shut, take them off – and not a second before. Sunglasses are not anywhere good enough, they actually make it worse because your pupils dilate and try to let in more light, making a bigger target for the laser.
Plus, when you look this good, you’ll just want to wear them everywhere. Laser safety goggles are the only thing that will protect your eyes from laser light. Zero exceptions. They are the very first thing you should buy, and cannot be substituted.
Alright, deep breath. Lecture over – got your safety goggles? On to Concept and Design!
When I first built Dr. Altman’s Amazing Laser Music Can, I was captivated. This is true science! Gorgeous laser light that was unimaginable before the development of quantum physics. Patterns generated by varying partial derivatives of the surface of a rigid plate on a vibrating membrane – and you thought calculus was boring!
I loved it, and after playing with it a bit, I wanted more. I read up on laser light shows used in raves and clubs, and found they relied on on mirrors attached to finely controlled motors, directed by panels of digitized electronics. First off, I can’t afford that. Secondly, it seemed rather convoluted that audio had to be digitized, fed into a program, translated to thousands of tiny precise mirror movements, and then you could finally see an effect – when I could do something similar, albeit not controlled to quite as fine of a degree, with a balloon and a mirror.
So what to do? Well, it seemed that the only affordable approach that was relatively simple to build would have to be similar to the Five Dollar Laser Show approach – music causes a mirror to vibrate, a laser bounces off of it, and a pattern is generated. I knew I wanted a brighter laser, and I wanted lots of those patterns.
Splitting one strong beam into lots of smaller parts seemed to be more practical than buying 200 lasers that would all bounce off one mirror – and something called a “diffraction grating” fits the bill perfectly. This is another example of the magic of physics – it’s sort of like a window screen fixed in glass that’s so incredibly fine you can see through it and not notice the individual wires. They’re so tiny that the laser goes through all these little holes, and the wave-like nature of light causes each of these little parts of the laser light to “interfere” with each other.
What do I mean by “interfere”? Well, let’s think about a wave property we’re familiar with – waves in water. If we drop one rock in water, we can see nice round ripples moving away from the rock – there’s no interference occurring here. If we drop two rocks at the same time, the situation changes. At first, we get normal circular ripples moving away from each rock, but then the ripples hit each other – and start to interfere with each other like we see in the video above. In places where the peak of two ripples meet, we get a ripple twice as big. In a place where the peak of one ripple and the trough of another ripple meet, we get no ripple at all!
Now obviously this diffraction grating is more complicated than ripples in water – but something similar happens on a very small scale. Laser light, which like all light has a wave-like nature, comes out of all the little holes in our diffraction grating and interferes in a very regular and predictable way, giving us all these wonderfully split beams. Remember – it’s not the little holes in the diffraction grating alone that split up the light, it’s the splitting and how light interacts with itself, the “interference”.
Enough theory, here’s the concept. A powerful laser reflects off a mirror mounted on a speaker, and then goes through a diffraction grating. This will create not just one laser pattern based on the vibration of the speaker, but hundreds. Sweet.
There are a huge variety of ways to modify this basic concept with more mirrors, more diffraction gratings, rotating mirrors/gratings, extra lasers and speakers – but I figured that I should probably build the first version to be as simple as possible. If engineering has taught me anything, it’s that the gap between design and execution is a bit more involved than we like to admit.
Now that you have a handle on the concept and design – on to what you need to build it!
I’ll be honest – I didn’t take anywhere near enough pictures of this. After the first hour I quickly descended into a geek trance and emerged a few hours later, slightly disheveled and holding a working working laser show but possessing only 13 pictures, many of which were terrible and irrelevant. So I apologize, and I’ve tried to make everything as clear as possible in the instructions themselves.
Power Supply and Control
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.
Cut out appropriate holes for the receptacle (generally a circle) and the switch (generally a rectangle). For the receptacle hole, I used an old soldering iron that I speared into the plastic – feel free to say “THIS… IS… SPARTA!!!” while doing so. For the hole for the switch, I used a Dremel tool and cleaned up the edges with the old soldering iron.
Solder up the receptacle, the switch, and two leads that you will eventually connect to the laser driver board. Use electrical tape to cover up any exposed contacts. It’s up to you to make sure you wire the switch correctly – there’s a ton of different ones out there, make sure to read the specifications. Don’t worry if it doesn’t work, there’s really only one other way to wire it.
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 put on your laser safety goggles. You can take them off if you leave the room to go to the bathroom or something, but trust me, when you look this good, you’re gonna want to leave them on.
Now we can solder those leads to the laser. Be careful that you don’t use excess solder and connect the two power pins to each other! This can always be fixed, but it’s easier to do it right the first time around.
Now fix the laser driver board to a part of the box. I picked the side and set it vertically to leave the most available space, and used a glue gun to mount it since there weren’t any easy screw mounting points. 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. You can see how I chose to mount everything in the picture at the end of this article.
Don’t worry about mounting the laser itself yet. 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. You only see a dot instead of bright green glare because you’re wearing your safety goggles. You are wearing your safety goggles, right?
Alright, now we have a working laser that we can easily turn on and off! Now turn off the switch and remove the power adapter (do both!).
Laser Modulation (or, a little mirror that moves)
Now we need to grab those headphones and take them apart. It’s a lot less complicated than you think. Each set of headphones will be different, just keep taking out screws and gently cutting away plastic until you’re left with the speaker and cord from one side. There should be two wires (or possibly the two wires are covered in plastic so they look like one wire) leading from the cord side into the headband thing. Cut this wire, and use electrical tape to nicely cover the exposed ends of each. I don’t think connecting them is a good idea (drain too much power?), but like I said, electrical engineering is not my specialty. Feel free to comment.
Now you should have one speaker attached to a cord that you can plug into an iPod or a stereo. Plug it in and start playing music to make sure it all works. Now look at the speaker as music is playing – if you’re lucky, it’s nice and exposed, and you can see the speaker cone moving back and forth. If you aren’t, it’s covered in a plastic mesh or similar. Cut it away carefully (I used an old soldering iron again, being very careful not to hit the speaker itself) so you can see the speaker. We want to be able to glue the little circular mirror on the speaker itself.
Grab your glue gun, dab a bit of glue on the back of the mirror, and quickly and carefully place it right in the middle of the speaker, ensuring it remains flat. Don’t get any glue on the mirror itself, and use a tissue to wipe off any fingerprints (or, if you wear glasses, use your cleaning cloth).
Now we want to place the headphone/mirror inside our project box, and align the laser correctly so it bounces off the mirror. I found it easiest to first place the speaker at a 45 degree angle, and fix it in place at one of the box with the glue gun. I also cut a small semicircular notch in the side of the box to give the headphone cable an easy mounting and attachment point in the box.
Ensuring the laser remained parallel to the bottom of the box, I then I adjusted the height of the laser with a mounting made of popsicle sticks. The end result is a beam which bounces off the mirror at a 45 degree angle and then heads straight for the ceiling. This is the easiest way to mount the laser so you don’t need to worry about it hitting your eyes on a regular basis.
Mounting the Diffraction Grating
Now we need to place the diffraction grating so that it intercepts the laser being reflected off the speaker, and breaks it up into hundreds of different beams. We want to place the diffraction grating directly above the mirror if you’ve aligned your laser with a 45 degree reflection angle.
Use a Dremel tool or similar to cut a hole in the top of the project box that’s slightly smaller than the diffraction grating. Then mount the diffraction grating in place with the glue gun.
Final Testing and Assembly
You should now have something that looks somewhat like this.
Don’t worry about that tan circuit board with the LEDs attached the to the diffraction grating, they’re some lights that came with the specific type of headphones I used. I kept them in because they looked kind of cool, not for any technical reason. You don’t need them. Check to make sure that the laser turns on, and that it bounces off the mirror correctly at rest and when music is playing. Then box it all up, and you’re ready to go!
You can see that I’ve added in some ventilation holes above the laser and main power transistor. Do this! The laser will produce heat as part of it’s operation – it’s not normally a big deal, but a sealed box has a way of drastically increasing temperatures.
I hope this helped you – and if you have any questions, just post in comments!
I’ve been on a bit of a laser kick lately. I was searching through YouTube and came across Dr. Altman’s “Amazing Laser Music Can” which I thought was a very impressive effect for very little money. I had a spare Sunday afternoon, and decided to make one for myself. If you’re the impatient type, here’s what the final product produces, not too shabby:
I started off at the local dollar store, which amazingly enough had everything I needed for about five dollars.
- Three laser pointers, $3. This personally boggles my mind – an electronic device, relying on the most advanced theories of physics humans have developed, the absolute cutting edge of research less than 60 years ago, now sells for 99 cents. You don’t need to use precisely three, but you’ll probably want at least one. Or else bitter disappointment awaits, because you need a laser for a laser light show.
- A package of ballons, $1.
- A small mirror, $1.
I also had a few things around the house.
- A can.
- Duct tape.
- Zip ties.
- Clothes pins.
- Popsicle sticks.
If you need to buy them don’t worry, you won’t blow your budget. Plus, once you have an excess amount of duct tape and zip ties you’ll wonder how you ever lived without them.
What we’re trying to do is mount a laser so that the beam bounces off a mirror attached to a membrane (aka balloon) stretched across the mouth of the tube. When the membrane vibrates, the path of the laser will be changed in a semi-periodic manner, leading to (hopefully) beautiful patterns that sync up to sound.
Mounting the Lasers
You can do this with one laser, but since the lasers were so cheap I picked up a few. The first thing we need to do is zip tie (or glue, or whatever) one side of the clothes pin to the popsicle stick. This will create a nice little angled place for the laser to mount to.
Then, we need to attach the laser. Another zip tie does well for this, really crank it down to make sure that it isn’t going anywhere. Finally, we need to create some sort of method to ensure the laser remains on for an extended period of time without us having to hold down the little button by hand. Zip ties to the rescue again! Just position it on top of the button, and slowly tighten it until the laser turns on. The zip tie should then be loose enough that you can move it back and forth to turn the laser on and off for as long as you like.
The final product can be seen above. Note that the middle zip tie is loose enough to be moved around as necessary. Make as many of these as you want.
Now we need to create the membrane that will vibrate, and that we’ll attach our mirrors to. Remove both ends of the can, by whatever means possible. I suggest finding a can where you can use a can opener (oddly enough) on both ends.
Once you’ve removed both ends of the can, cut the end off a balloon and stretch it over one end of the can. Make sure it’s nice and tight, and then use duct tape around the side of the can to keep it all in place.
The assembled membrane may be seen above.
Now to put it all together. The only thing we need to do still is create tiny little mirrors that the lasers will bounce off of. I would suggest breaking a small mirror on your kitchen table, and make sure to get small pieces of glass everywhere. Your girl/boyfriend or significant other will love this, trust me.
Attach the mounted lasers around the edge of the can with duct tape, and turn them on. This helps us to place the mirrors accurately. I used a little roll of duct tape, stuck it to the bottom of the mirror, and then placed the mirror as the laser indicated. Make sure that you stick the mirror on securely, the membrane will vibrate rather vigorously and the mirrors have a tendency to bounce off unless you’ve made sure they’re on.
And that’s it! This little device provides a ridiculous amount of entertainment for five bucks. I’d suggest placing it on your subwoofer vent if you want it to sync up to music (that’s what I did for the video), or singing into it – just try not to wake the neighbours.
If you liked this, check out the Ultimate Home Laser Show.