Instructables user peterdr has put together a really excellent tutorial on how to build his CT-1 open-source hardware intervalometer for Canon and Nikon digital cameras. There's more info about the project at his personal website, and a parts kit is for sale on Amazon.com.

Last week I wrote about how to construct a simple sheet metal "bridge," which, in combination with an ice cube bucket and an olive jar, makes an effective pneumatic trough for collecting gas samples over water. This week I'm going to show you how to use this apparatus to generate and collect pure oxygen, and how to use that oxygen to observe the brilliant blue flame of sulfur oxidation.

CAUTION

As a general rule, flammable greases like petroleum jelly should not be exposed to pure oxygen. There is no appreciable danger in this experiment, which involves only a small volume of oxygen at atmospheric pressure in a container with a free lid, but if you are working with larger volumes of oxygen, oxygen under higher pressure (as in a cylinder), or (most emphatically) liquid oxygen, do not use grease or other readily oxidizable materials in constructing apparatus.

Tools:

• Pneumatic trough apparatus from part I
• Small piece of plate glass (I used the mirror from a makeup compact)
• Lighter
• Twisted wire sample loop
• 250 mL Erlenmeyer flask (I got mine from The Maker Shed)
• #7 two-hole rubber stopper to fit Erlenmeyer (mine came from this assortment)
• Two 80 mm lengths of 5 mm glass tubing to fit stopper (such as this)
• Approximately 18" length of 5/16" OD x 3/16" ID PVC tubing to fit glass tubing (common hardware store item)

Materials:

• Water to fill bucket
• Elemental sulfur powder (also called "Flowers of Sulfur," available at some drugstores and here.)
• 3% hydrogen peroxide (common drugstore item)
• Manganese dioxide (can be recovered from an alkaline dry-cell battery or purchased here)
• Petroleum jelly (drugstore)

My local library picked up on the festive trend of Cardboard Tube Fighting. The Boston Globe covered the preparations:

The group discovered cardboard tube fighting last summer in time to incorporate a bit of it into a presentation on Greek mythology at a reading program party.

The weapons are cylindrical pieces of thick cardboard about 4 feet long. The appeal, explains young-adult librarian Ellen Snoeyenbos: "It's totally ridiculous.''

As word of mock combat with reliably harmless weaponry spread among the town's youthful warriors, Snoeyenbos and the Bookmarks seized on the fund-raiser as a chance to exploit their discovery of the fighting fad made popular by YouTube.

Saturday's event will feature one-on-one tournaments, guild-on-guild skirmishes (up to 10 fighters per team), "and an all-out battle for possession of the Royal Crown,'' according to the club.

They've gathered hundreds of tubes, and youth of all ages are uparmoring in a pulpy way.

More:
Cardboard Tube Fighting League

Troy Davis created some very awesome recreations of Devo's signature Energy Domes. Beginning with a tiered stack of fiberboard for the mold, through to vacuum forming, paint job, and padding - a thorough explanation can be found in his project pictorial. sweet.

Check out this homebrew accelerometer controlled USB gamepad using a PIC18F2550 from Starlino. You'll find code and schematics on their site.

The code for the firmware was written in PicBasic Pro and it implements a HID USB device with 2 axes and 4 buttons (only 2 buttons connected in the prototype). The device is detected by Windows XP/Vista as a standard USB gamepad and can be used with many games and applications.

I am using a 2 Axes Buffered ±2g Accelerometer from DIMENSION ENGINEERING, it has a built in voltage regulator that allows powering the accelerometer directly from the USB bus (5V)

Instructables user jvalal didn't like the look of his Powermat inductive device charging station, so he stripped out the guts and "re-skinned" it with a handmade wooden case.

Unity3D hacker Pieter Floris writes in to say that he's Patrick Gutlich has finally got his Arduino connected compass controlling a camera in Unity3D. The barrier of entry continues to be lowered by projects like this. Kudos, Patrick!

More:

Updated Power Glove with Bluetooth and Arduino

As the holidays approach this year, money is tighter than ever for everyone. When thinking about gifts to give, consider the gift of DIY electronics and kits, not only could a loved one learn a new skill, but it could start them on a journey to a wonderful lifetime hobby, possibly a career! Helping someone learn electronics is more than just giving a circuit board and a bunch of parts, you're giving the gift of time, hours of new experiences exploring the wonders of engineering and science. In the end, they'll also have something to show and share!

So let's get started. I've put together my 20 favorite (mostly) under $20 electronic kits and resources, some are from the Maker Shed, some are from other places (SparkFun, Adafruit, Instructables, TechShop, Solarbotics, Evil Mad Scientist Laboratories, Parallax). Many of them are open source hardware projects, so if $20 is still too much, you might be able to put these together on your own and print out the instructions for free too! Our gift guides are meant to inspire your suggestions, so if you know of a great $20 or under electronics kit, post it in the comments!

If San Francisco City Attorney Dennis Herrera gets his way a generation of club goers will miss out on the sickly sweet tang of caffeinated alcohol beverages like Sparks, Four-Loko, and Joose. Yet, all is not lost. A group of enterprising practitioners have seized the opportunity to handcraft a batch of Bathtub Sparks in an attempt to recreate the extreme libation.

The following drink was reverse-engineered from a vintage can of caffeinated Sparks and rigorously tested via blind taste-test by SFoodie and four people who agreed to come over to the author's house and drink this stuff, plus two random guys on the street who should be applauded for their daring and general zest for life.

Related:

• HOW TO make Moonshine Whiskey


• Garbage bag + rice cooker = alcohol still


• Home Distillation of Alcohol

Jim did some experimenting with homemade thin-film zinc oxide and zinc-tin oxide, developing his own homemade transistors devices -

I did manage to achieve (with a liquid dielectric) voltage and current gain, as well as construct a functional astable oscillator using two of the devices constructed on a single substrate. While the speed of the devices (due to the liquid dielectric) is such that they are only interesting as a technology experiment, they've been a lot of fun to experiment with.

I've needed a repair stand for a long long long time now. But....damn those things aren't cheap. Thankfully, I've got more than my share of blue collar blood in me....so I decided to build one. The process couldn't have been easier. I did a quickle google search on home made repair stands and saw some interesting solutions. In the end, I went with my own variation.

Mark just boinged a link to this cool magazine how-to from 1961 (.pdf) by Roy L. Clough, Jr. It's hosted at Cigar Box Nation. [via Boing Boing]

Did you know that we offer PDFs of some of the popular projects and primers that have appeared in MAKE magazine? You can always subscribe to the Digital Edition of MAKE or buy a single back issue with the project you're interested in, or you can just download the specific PDF you're looking for. Each download is $1.99.

Here's a list of all the PDFs we currently offer:

The Night Lighter 36 Spud Gun: (Volume 03, page 108)
The Brain Machine: (Volume 10, page 88)
Cigar Box Guitar: (Volume 04, page 77)
Compressed Air Rocket: (Volume 15, page 102)
Wind Power Generator: (Volume 05, page 90)
Kitchen Floor Vacuum Former: (Volume 11, page 106)
Primer: Working With Carbon Fiber: (Volume 09, page 164)
Primer: Printed Circuit Boards: (Volume 02, page 164)
Primer: Welding (Volume 03, page 158)
Primer: Moldmaking (Volume 08, page 160)

J44 outlines his steps for converting a basic gaming light gun into a custom Laser Tag-like system, including gun and head mounted 'hit' detectors (a la Photon) -

I hope many of you will find this instructable useful and will go on to build your own duino taggers. There is much scope for improving and upgrading this system outlined here. If you do go on to improve on this duinotagger please share your work and hopefully in time the system will evolve into a much richer gaming experience.

Related:

Build your own laser tag system

When I put together my Chumby Guts kit, I had to stop and scratch my head a few times because I didn't know how to orient a part or which screws to use. I filmed the second time around, to share with you how easy it comes together! Now all that's left is to build a plush enclosure for it. Keep an eye out for an upcoming CRAFT Video about that!

Subscribe to the MAKE podcast in iTunes, or download the m4v video.

More:

• Chumby in a box
  
• The Chumby has landed!
  
• Custom case for Chumby Guts
  
• Chumby Guts -- so delicious!
  

In the Maker Shed:

Chumby Guts

Kent was impatient at having his Chumby Guts laying loose on the table, so he took to the box that it came in. This is a good way to see what the casing process entails and considering what it will ultimately need before committing to a proper case. Think of it as a Chumby case sketch model. Some of the other possibilities we've heard are cigar box Chumby and Teletubby embedding (called either TeleChumby or ChumbyTubby). MAKE Flickr pool member Pauric posted a set of photos showing how he gutted his first gen Chumby and installed it in a nice wooden case.

How are your Chumby Guts doing? Post up some Chumby photos in the MAKE Flickr pool, and send us some tips in the comments.

More:

• The Chumby has landed!
• Custom case for Chumby Guts
• Chumby Guts -- so delicious!

In the Maker Shed:

Chumby Guts

Mark @ BoingBoing points us to this homemade water purifier build by a retired Russian engineer.

I love etching my own PCBs. It's a great way to incorporate some of art-school skills with my love for DIY electronics. Up until now, I'd always used traditional ferric chloride to etch my boards, though I'd heard many sing the praises of an alternative etchant easily made from common ingredients. Tired of mail-ordering ferric and dealing with proper disposal, I decided to give cupric chloride a try.

Following Open Circuits' recipe, I picked up some muriatic acid from the local hardware store and a bottle of hydrogen peroxide 3% from the pharmacy. After setting up next to my big window fan, I slowly added 16oz of the muriatic to an equal amount hydrogen peroxide, resulting in a clear solution. Shortly after immersing my masked PCB and agitating a bit, the etchant turned a brilliant green hue as it began work on the exposed copper. Several minutes of gentle sloshing left me with a perfectly etched board - plus a etchant that can will last me a very long time. For me, that's the real 'selling point' of cupric chloride - by oxygenating (air-bubbling) or adding some more H2O2 to the solution, I'll be able to refresh this batch once it's spent - awesome. I'm left wondering why I hadn't tried this sooner!

Although it sounds like some kind of euphemism from Brave New World, a "pneumatic trough" is actually a very handy piece of classic chemistry lab kit. Besides providing a convenient means to collect samples of pure gases for various experiments, a pneumatic trough with a graduated container allows the easy volumetric measurement of reaction yields for gas-producing reactions.

If that all sounds too complicated, don't sweat. What I'm going to show in this tutorial is simply how to build a simple piece of apparatus that allows you to collect pure gas samples over water. You can collect carbon dioxide, oxygen, hydrogen--almost any gas you can generate and direct down a hose.

It seems like a simple enough bit of equipment: all you need is an upside down container suspended in a bucket of water. Finding a convenient way to set that up, however, is tougher than it sounds. The pneumatic trough presented here, which uses a sheet metal "bridge" to secure the glass column, is by far the most painless and economical way to make it work that I have found. The basic idea is derived from illustrations in Robert Brent's 1960 Golden Book of Chemistry Experiments (from which the title diagram is taken), but the addition of an aperture shaped to accept the threads of a glass jar is of my own devising.

I'm thrilled to share the EyeWriter with you all:

Behold the latest ocular assault weapon from the Graffiti Research Lab, openFrameworks, The Fat Lab and The Ebeling Group: The EyeWriter. It is a low-cost eye-tracking apparatus + custom software that allows graffiti writers and artists with paralysis resulting from Amyotrophic lateral sclerosis to draw using only their eyes.

The goal of the hardware component of the EyeWriter project is to make the most simple and inexpensive eye-tracking head-set possible to use with the "EyeWriter" software suite. Obviously, there are numerous ways to make eye-tracking hardware. Many of these designs, especially those produced for academic research projects (Open Eyes ), have already been published openly on the internet.

Our functional design specifications are as follows:

1. The EyeWriter should be as inexpensive as possible
2. The fabrication and assembly of the system should require only common hand tools
3. Whenever possible components and parts should be available for purchase locally versus online
4. The camera should produce 640 x 480 NTSC video
5. The camera should be sensitive to near-field IR light
6. The camera should not auto-iris (or auto-iris should be disabled in the camera's driver).
7. IR LEDs should be used to illuminate the pupil

Beyond that its up to you... this instruction set details a solderless variation of the EyeWriter that uses a hacked PS3 Eye and a pair of stunnas we bought on Venice Beach and suggests other possible EyeWriter configurations.

Yes, that's right, watch TemptOne tag buildings (with light) even though he can only move his eyes. We live in the future, and this project makes me feel so warm inside. The whole project is open source.

Racking her brain for a quick-and-dirty way to make microfluidic devices, Khine remembered her favorite childhood toy: Shrinky Dinks, large sheets of thin plastic that can be colored with paint or ink and then shrunk in a hot oven. "I thought if I could print out the [designs] at a certain resolution and then make them shrink, I could make channels the right size for micro­fluidics," she says.

To test her idea, she whipped up a channel design in AutoCAD, printed it out on Shrinky Dink material using a laser printer, and stuck the result in a toaster oven. As the plastic shrank, the ink particles on its surface clumped together, forming tiny ridges. That was exactly the effect Khine wanted. When she poured a flexible polymer known as PDMS onto the surface of the cooled Shrinky Dink, the ink ridges created tiny channels in the surface of the polymer as it hardened. She pulled the PDMS away from the Shrinky Dink mold, and voilà: a finished microfluidic device that cost less than a fast-food meal.

Khine began using the chips in her experiments, but she didn't view her toaster-oven hack as a breakthrough right away. "I thought it would be something to hold me over until we got the proper equipment in place," she says. But when she published a short paper about her technique, she was floored by the response she got from scientists all over the world. "I had no idea people were going to be so interested," Khine says.

Let's get started with the CupCake electronics assembly. I ordered the deluxe kit from batch #8, so most of the electronics were already assembled. Yay! Not that soldering isn't fun, but I'm happy to skip the soldering for this build and get to printing faster!

The stepper boards:

Not much to do here since the board is already soldered together. However, you do have to add the insulation-displacement connector (IDC) to the ribbon cables, and perform a simple test.

All you have to do is insert the ribbon cable into the plastic IDC connector and squeeze it closed. You might want to use some pliers to help snap the top down.

Take notice of the arrow on the connector. The brown wire is the index wire, and it should be directly above that arrow on both ends of the cable.

Rinse and repeat. You need to make three cables, each with an IDC connector on the end.

From the MAKE Flickr pool

Alas, old friend VHS - has it really come to this?! Doomed to spend the rest of your media lifecycle supporting stacks of newfangled digital media. *Sigh* … and how much longer 'til we see those same DVD cases supporting a heap of flash drives/etc? I'll keep an eye on farnea's photostream to find out.

Features:

• Cool glowing blue tube with 8 digits, PM dot and alarm on/off indicator
• Adjustable brightness
• Alarm with volume adjust
• Precision watch crystal keeps time with under 20ppm (0.002%) error (< 2 seconds a day)
• Clear acrylic enclosure protects the clock from you, and you from the clock
• Battery backup will let the clock keep the time for up to 2 weeks without power
• Selectable 12h or 24h display
• Displays day and date on button press
• 10 minute snooze
• Integrated boost converter so it can run off of standard DC wall adapters, works in any country regardless of mains power
• Great for desk or night table use, the clock measures 4.9" x 2.9" x 1.3" (12.5cm x 7.4cm x 3.3cm)
• Completely open source hardware and software, ready to be hacked and modded!

Tim Saylor recently wrote in to me about the Gingery-style charcoal foundry he built for Chicago's hackerspace Pumping Station: One. There's a write-up here and a good Flickr set showing construction and use of the furnace to melt aluminum here, including some really pretty shots of the fire and sparks at night. [Thanks, Tim!]

Impress your friends and coworkers with these easy-to-make edge-lit holiday cards by Evil Mad Scientists Laboratories! This time around they used PETG polyester, which is easier to cut than acrylic.

More:

How-To: Make "edge-lit" holiday cards

An engineer's solution to the jack-'o-lantern problem if ever I saw one. [via There, I Fixed It]

MirlitronOne explains how to turn a Velleman MK107 LED Running Light kit into a simple 8-step sequencer for use with analog synthesizers. A handy kit hack, but it's also not too much work to build one from scratch.

Related:

Sequence it!!

This kit has everything you need to build a MakerBot CNC and get started in DIY digital fabrication. Not only have we included all of the parts you need to build a CupCake CNC, but we've also included all the tools that you'll need to put it together and have the build go smoothly.

What exactly is included in the $950 deluxe kit?

• The laser-cut parts to assemble a CupCake CNC machine.
• 3 x NEMA 17 motors to drive your machine
• The nuts, bolts, and various hardware to assemble it.
• The belts and pulleys for it to move things around.
• All the bearings to make your machine nice and smooth.
• The highest quality precision ground shafts for the X and Y axes we could find.
• Pre-assembled 3rd generation electronics to drive it better, faster, and stronger.
• Magnetized, detachable build platform to make removing your finished prints easier.
• Pinch-wheel Plastruder to make things in plastic.
• 1lb of natural ABS to get you started printing in 3D.
• USB2TTL cable to talk to it
• cat5e cables to wire things up
• Standard ATX power supply
• Tools kit with all the hex keys, wrenches, and other bits you need to construct it.
• Full 5lbs of ABS plastic so you can print your heart out (in addition to the 1lb of ABS)
• Extra acrylic build surface, and a spare build platform
• SD card to buffer your prints

You can also save some money by purchasing the Basic CupCake CNC Kit for $750. Check out the link for more information about what is, and isn't, included in the basic kit. Then again, you could always build your own from scratch since it's totally open source.

Let the unboxing begin:

The first thing I found was a nice letter from the MakerBot team and a couple of postcards. I'm going to keep these filed away in a safe place. Maybe one day I'll be on the Antiques Roadshow and the host will let out a delighted *gasp* when I whip out my original, signed MakerBot Industries letter. Hey, you never know?!