This problem has already been solved in the chess world with the Elo rating system, a statistical approach that requires frequent competition in order to generate statistically significant results. Unfortunately competitors in sports like mixed martial arts or boxing do not compete nearly as frequently as chess players (for obvious reasons) and this approach drowns in a sea of statistical noise. Typically combat sport rankings are done by a knowledgeable observer by hand, through consensus of many observers, or by models with a large number of tunable parameters. It is very interesting to consider that humans appear to be able to easily determine who should be ranked highly, and that many algorithmic approaches largely match these evaluations but make some seemingly obvious mistakes. My goal was to find an approach that produced rankings that seemed sensible to a human observer with a minimum of tunable parameters (preferably none).

Data Structure

The initial step is to structure our data in a sensible way. We have a large number of participants, connected by individual competition which can either result in a win or a loss. One way of structuring this data would be in a directed graph, where competitors are represented by nodes and matches as edges with direction defined by who wins or loses. We seem to be focused on losses (or win/loss ratio) as the biggest factor – a competitor with 40 wins and zero losses is typically regarded as better than a competitor with 60 wins and 20 losses. Let’s set the direction of the edge from the losing competitor to the winning competitor. A “good” competitor’s node will therefore have many incoming edges and few outgoing edges, and tend to be at the center of force-directed graph layouts.

Evaluation Algorithms

There are many possible evaluation algorithms which will produce a ranking from this data structure. After many trials, two appeared to stand above the rest.

1. The first is recommended in the journal article Ranking from unbalanced paired-comparison data by H.A. David published in Volume 74, Issue 2 of Biometrika in 1987.
2. David also discussed the Kendall-Wei algorithm in his paper, of which Google’s PageRank algorithm is a special case. PageRank is used to rank webpages which are represented as a directed graph based on the concept of network flow, and may also be applied to other directed graphs including our case. The PageRank algorithm contains one tunable parameter, a damping factor which is currently set to the default 0.85.

It was found that both algorithms seemed to emphasize different aspects important to MMA ranking. David’s “Unbalanced Pair Comparison” emphasized a grittier statistics-based approach, highlighting fighters such as Anderson Silva, Rashad Evans, and Jon Fitch. Google’s PageRank seemed to take a more social approach emphasizing fighters with a wide range of quality opponents, like Georges St-Pierre, Matt Hughes, and Forest Griffin. It was very interesting how one algorithm appeared to highlight the “hardcore mma fan” perspective, while the other seemed to be pulled straight from the UFC head office.

It was decided that both would be calculated, scores normalized, and used in combination to generate a consensus ranking similar to consensus rankings generated from human experts. This was inspired by IBM’s Watson which uses a consensus of multiple algorithms to evaluate answers to trivia questions. Two possible improvements are hypothesized but undertested:

1. Perhaps additional independent ranking algorithms incorporated in this consensus would improve accuracy. The big issue appears to be “independent” algorithms which do not simply restate the work of other algorithms, and of those, finding algorithms which display ranking behavior useful for our application.
2. Unlike Watson, confidence levels are not used. This would be a useful addition given situations like extreme upsets. A newer beta version of this ranking system determines if highly ranked fighters coincide with centrality metrics in an attempt to implement this, but is not complete at this time of this post.

Results

The ranking system was run on every UFC event from UFC 1 (November 12, 1993) to Fight for the Troops 2 (January 22, 2011). Both algorithms are shown ranked alone for comparison, and their scores were equally weighted to produce the final results.

First up are the lightweights – and the results aren’t too shabby. No one seems to want to admit it due to his sometimes snooze-inducing style, but Gray Maynard is a beast who is likely to cause B.J. Penn significant issues if they ever fought. Frankie Edgar deserves to be right up there but not number one, and chronically underrated George Sotiropolous and Jim Miller round out the pack.

Georges St-Pierre is the obvious frontrunner at 170. Matt Hughes at number two is a bit more debatable, but a long title reign and consistent quality opposition provide a reasonable rationale. Josh Koscheck is perpetually always the bridesmaid, never the bride at third, and Martin Kampmann and Dennis Hallman round out a somewhat thin division.

Anderson Silva provides another easy choice for number one at 185lbs. Both Jon Fitch and Yushin Okami deserve their spots with a consistent if slightly dull record. Michael Bisping has slowly been grinding his way up the charts, and Nate Marquardt rounds out the top five.

Rashad Evans appears to have made a sensible call waiting for his title shot at UFC 128. The hypercompetitive light heavyweight division is always a tough one to call. A split in the consensus between the two algorithms produces a top five that seems to emphasize number of fights in the Octagon, with champion Mauricio “Shogun” Rua a surprising fifth. Too early to call Evans over Rua? Only time will tell.

I initially disagreed with Frank Mir as number one here – Cain Velasquez seems to be the obvious choice. But the ranking process seems to trust number of fights over new hype, and the rest of the top five is bang on what I would choose. You can’t win them all – or perhaps I’m just being unfair to Frank Mir.

Conclusions

The approach produced excellent rankings from UFC-only data, largely coinciding with established and more complete authorities like FightMatrix. The approach used two ranking algorithms which traversed a directed graph, and produced scores which were normalized and added to produce a final score which was sorted to produce final rankings. One tunable parameter (PageRank damping factor) exists in the model, but was left at the default value of 0.85. Further work will focus on additional ranking algorithms which may be incorporated into the consensus, parametric analysis of the PageRank damping factor, and determining confidence scores.

Acknowledgements

The NetworkX package for Python was critical for this project. I came across Mixed Martial Arts vs Graph Theory shortly after starting work on this. Many thanks to Jack Rusher for highlighting interesting algorithms and providing a respite from entering most of the data by hand.

Here’s some of the best free high-definition content I’ve found on the web, if you know of any more please let me know!

Gravitas

Gravitas is a project by John Dubinski of the Department of Astronomy & Astrophysics at the University of Toronto. He works on visualization of galaxy dynamics, and his goal is to “use supercomputer simulations of realistic model galaxies to illustrate these slow and majestic dynamical processes on an accessible timescale and so breathe life into the iconic images of galaxies created by the world’s great telescopes”. He succeeds brilliantly, and has produced a set of captivating animations, some in HD.

Download Future Sky (Quicktime 720p) and Spiral Metamorphosis (Quicktime 1080p).

Fractal Zooms

Eric Bigas has a great website with several fractal animations, including a few in HD.

Cherry Blossom Hexagons is a zoom into a Barnsley fractal, available in 720p XviD or 720p H.264.

19th Hole Terraces is a zoom into a Mandlebrot set, available in 720p XviD or 720p H.264.

Copperplate Chevrons is available in 720p XviD.

Hubble Space Telescope

The European Homepage for the NASA/ESA Hubble Space Telescope has tons of great HD content. Dr. Joe Liske at the European Organization for Astronomical Research in the Southern Hemisphere hosts a video podcast which you can subscribe to in 720p or full HD 1080p. They also have a HD video archive of broadcast quality footage, like this flythrough of the Hubble Ultra Deep Field.

For other HD space videos, NASA has a HD video archive with a section dedicated to Hubble. The Jet Propulsion Laboratory has an HD archive of their own, click “HD” at the bottom to browse.

Bottom Line: An amazingly comfortable and well manufactured pillow that will lull you off to sleep – if you can stomach the steep price tag.

$199 MSRP, available from Essentia.

Introduction

Once you get a memory foam bed, you tend to evaluate every other foam product in your house with a critical eye. The couch seems just a tad lumpy. You feel bad about having a guest bed made of mere conventional foam. And your pillows, previously ignored as an afterthought in your bedroom, now seem lacking that viscoelastic comfort you’ve come to know and love.

Alright, maybe it’s just me. But back to pillows – making your own seems to be well within the realm of possibility given an appropriately large piece of memory foam and a hot wire cutter. Today however, we’re going to take a look at the latest and greatest pillow the commercial memory foam world has to offer – the Essentia Forma Spa.

If you’ve read my site you know that one of my major frustrations with the memory foam industry is the seeming willingness of some vendors to trade quality for cost while lying through their teeth about it. Getting a handle on the manufacturing process can allow us to determine if a memory foam vendor is truly top of the line or just doing their best to make it sound that way. I described the typical memory foam manufacturing process in What is Memory Foam?, but this doesn’t apply to Essentia. While typical memory foam is made of polyurethane foam with additives to create viscoelastic behaviour, the Essentia process involve putting a latex foam through a similar process. The result is a memory foam that is supposedly more breathable, more eco-friendly, and with less offgassing.

First Impressions

The package arrived after a slight delay, but hey, it was the courier’s fault and this is a pillow review and not a courier review. The pillow itself ships sealed in clear plastic inside a box. Slight damage to the box was noted as a result of shipping, but nothing unexpected and nothing that would cause damage to the pillow itself. It is packed flat, and is not compressed at all. No need to wait for it to expand like a memory foam topper.

After removing the pillow from the packaging, a slight odour is noted if you bury your nose in it. From six inches or more away, the smell is effectively undetectable. This is a giant improvement on all the previous memory foam products I have used, and a major point to consider if you’re allergic or sensitive to other memory foam products. A light fabic covers the pillow itself. The cover itself is not removable for cleaning, but if you’re like me and most of the civilized world, you use a pillowcase so this isn’t much of a concern.

The pillow itself threw me for a loop the first time I saw it – it’s much larger and flatter than I thought from the pictures on the website. This isn’t a good or a bad thing, it’s just something to note.

Comfort

This is what really matters – how you feel when you’re sleeping on it. In general, the pillow feels very supportive, yet yields easily. Frankly, it’s ridiculously comfortable in general. Everyone sleeps differently though, so I did my best to test it out in all possible positions.

Side Sleepers: This is how I tend to sleep, so I’ll go through it first. My first impression when I laid down on the pillow was that it was too high, and I was in for a neck-twisting delight. This worry quickly disappeared as I actally laid down on the pillow and my body heat worked it’s way into the formerly room-temperature foam over the next 5 minutes.

Essentia claims consistent performance from 1 to 30 degrees Celcius – while it’s certainly far better than polyurethane based foams (it doesn’t get that “stiff” feeling if your room is slightly chilly), there is certainly some degree of temperature responsiveness.

Back Sleepers: This had the same initial worry of being a bit too high, but again, I think this is largely psychological. I tend to move around a bit if I’m sleeping on my back, and I found one very interesting property – the foam “recovers” extremely fast. By this I mean that the dent you normally leave in memory foam will fill in very quickly. I found this made it easier to settle down and not toss and turn.

Front Sleepers: Personally, this is a no go for me. It works quite well if you sleep in a half-side, half-front sprawl which I tend to do, but if you sleep chest down like a corpse (honestly, who does this, you freak me out) it doesn’t work for me. Then again, my girlfriend will steal the pillow and spend a half hour hitting snooze in exactly this position.

Remember that personal preferences vary greatly – I would recommend this pillow for people who enjoy medium-soft to firm pillows. If you prefer very (emphasis on the very) soft pillows, it may be just a bit too high/firm for your tastes. This depends on your mattress as well – mine is a bit softer, if your mattress is more firm you’ll likely find that the height is a nonissue.

Conclusions

In short? It may seem a bit too high at first, but as soon as it warms up it’s a wonderfully comfortable memory foam pillow with zero odour issues out of the box. If you sleep on your side, back, or sprawled halfway between your front and side it’s almost too comfortable on cold mornings, but if you’re a corpse-style front sleeper you may want to try out similar products to make sure it’s what you want. The product is of extremely high quality, and this is reflected in the price – don’t expect it to be cheap.

Also see the Five Dollar Laser Show or the Ultimate Home Laser Show.

Laser Module

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.

Optics

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.

Audio

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!

Miscellaneous

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!

Skip to: Introduction – Laser Safety – Concept and Design – Parts – Assembly

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!

Instructions

Concept and Design

Parts

Assembly

Laser Safety

A Note on Shipping

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!

Skip to: Introduction – Laser Safety – Concept and Design – Parts – Assembly

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!

Skip to: Introduction – Laser Safety – Concept and Design – Parts – Assembly

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).

Alignment

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!

Skip to: Introduction – Laser Safety – Concept and Design – Parts – Assembly

What do I mean by this? Well, when you order a product from the United States as a Canadian, it’s stated that you must pay any applicable taxes, duty, and “customs brokerage fees”. Taxes and duty I can deal with, they’re a reasonable small fraction of the order, and one I regard as a welcome consequence of being a Canadian citizen.

Customs brokerage fees however, are the biggest screwjob to the Canadian consumer that appears to fly under the radar. You may think that this is some sort of charge from the Canadian government that is passed along to you – it isn’t. It’s pure price gouging by shipping companies, who themselves are this mysterious “customs broker”. You order a package, and when it gets to the door you’re told that you must pay an absolutely obscene amount of money in order to recieve it, often on the order of 50%-100% of the package value. Your package is effectively held for ransom.

Who does this? Well, when I was ordering electronic parts for the laser show, UPS tried to charge me 48 dollars for a 56 dollar order. I refused delivery, proceeded to phone them, and after a lengthy discussion had my fees (with the exception of duty and taxes, the only things you actually have to pay) waived as “goodwill” and accepted the $5.68 in charges the next day. But I’m not happy – don’t expect me to be grateful when you attempt to screw me, and then back down when challenged. I will never, ever ship with UPS again for any order and I urge everyone else to do the same.

Think I’m alone? Check out the reviews on epinions, or the feature CBC did. I’m not the only pissed off consumer out there.

So what can you do? Well, arguing with them on the phone might work once, but for a consumer in the internet age it’s simply not an acceptable option to spend a half hour on the phone every time you order something to reverse charges that shouldn’t have to exist in the first place. UPS apologists – save your breath. If you ship through USPS instead, they hand over packages to Canada Post at the border who kindly and easily manage to get through customs with a $5 fee for all packages valued under $1200. It’s clearly not rocket science.

So screw you, UPS. I will never, ever use your services again. What do I propose to do other than complain? Well, simple. Let’s have a law that provides the benefits of free trade for consumers rather than just multinational companies. Any shipping method to Canada must quote all brokerage fees as part of the shipping price. If I saw “Shipping: $67″ instead of “Shipping: $11″ I would have never ordered. They can manage to calculate shipping based on weight, so they can certainly calculate whatever extravagant cost for brokerage they want before showing up at your door.

It’s supposed to be a free market, so let’s treat it like one. I don’t care if UPS wants to charge $500 and demand a secret handshake on delivery, just be honest with me from the beginning. And consumers can decide for themselves, instead of being fooled and intimidated into accepting charges.

It’s deceitful. It’s dishonest. And it’s a slap in the face for the little guy who’s job can be shopped across the border with ease but who cannot purchase small items without incurring massive charges.

In conclusion – I urge you to write your MP or MLA to ensure free trade is free for individuals of all incomes and occupations, and use USPS in the meantime.