Make: Projects

Make: Projects - Pneumatic trough, part II

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)

Posted by Sean Michael Ragan | Nov 20, 2009 12:30 PM
Chemistry, DIY Projects, Education, MAKE Projects, Science | Permalink | Comments (2) | Suggest a Site

Intern's Corner: Test-firing the HHO rocket

Every other week, MAKE's awesome interns tell about the projects they're building in the Make: Labs, the trouble they've gotten into, and what they'll make next.

By Steven Lemos, engineering intern

Making the Hydrogen-Oxygen Bottle Rocket (that Adam Savage is posing with on the cover of the new MAKE, Volume 20) was a pretty basic endeavor, with the exception of the circuit. The original schematic diagram had a flaw in it, but only after we breadboarded the circuit -- twice -- did we catch it.

I guess that's the reason we MAKE interns build the projects that run in the magazine, so it's us who bang our heads against the table and not you. I will kindly take that cookie now.

The experience showed me that, sure, when working with electronics it's easy to misplace a component or wire, or completely miss something, which I already knew, but it's just as easy to have a diagram be the culprit. So a word to the wise (a word I'm sure all the experienced hobbyists have already discovered for themselves): if you take care when putting together these tedious circuits it will pay off, for if you can trust in your work, then you'll know the culprit lies in the plans, and you won't spend hours chasing that metaphorical wild goose.

Twice we breadboarded this bad boy before discovering an error in the schematic -- so you won''t have to.

But on to the actual launch. :) We had talked to the local electronics store owner, who at the time was making his own hydrogen using a more sophisticated apparatus, and who was interested in what we were doing with ours. So he came to watch, and brought along his professional pyrotechnician friend, who showed us how to make fuses with 12V and tiny resistors (basically the resistors pass so much current that the wire heats up and can act as a fuse to light stuff -- voilà, cheap fuses).

Our beautiful 2-stage HHO rocket ready for test launching -- before being crippled by a crash.

The first launch was a success, with the two stages going off rather quickly in succession, so we dialed in a little more delay time in the circuit before the stage 2 ignition. This was good and bad. We got more height out of the rocket on our second launch, but on its return it landed electronics side down. This resulted in our circuit behaving oddly.

So, not ready yet to call it a day, we began firing off only one stage at a time, adjusting the proportions of HHO (hydrogen and oxygen gases), water, and air, and testing the makeshift fuses, which worked fine for a single stage, but due to the time they take to ignite (3sec@12V) might not work for 2 stages.

We probably launched 12 times that day, attracting passersby. Good weather, new friends (who like blowing stuff up), and multiple launches. All in all, a good day. Houston, we have liftoff.

• Related: MAKE, Volume 20: "For Kids of All Ages"

Posted by Keith Hammond | Nov 18, 2009 09:33 AM
Electronics, Flying, Intern's Corner, Kids, MAKE Projects, Toys and Games | Permalink | Comments (7) | Suggest a Site

Make: Projects - Pneumatic trough, part I

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.

Posted by Sean Michael Ragan | Nov 13, 2009 12:00 PM
Chemistry, DIY Projects, MAKE Projects, Science | Permalink | Comments (6) | Suggest a Site

CupCake CNC build, part 3: The electronics

It's finally time to start building the CupCake CNC. The first thing you should do is read all the instructions. Don't pass by the 'mistakes to avoid section', it could save you some misery later.

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.

Posted by Marc de Vinck | Nov 12, 2009 02:30 PM
3D printing, DIY Projects, Electronics, Kits, MAKE Projects | Permalink | Comments (8) | Suggest a Site

CupCake CNC build part 2: Unboxing

I purchased my CupCake CNC Deluxe Kit from MakerBot Industries. This machine is from batch #8, and it's serial #000305. Future batches may be slightly different, so don't use this as an exact guide for making your own CupCake CNC. Here's what MakerBot Industries says about this version of the kit:

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?!

Posted by Marc de Vinck | Nov 10, 2009 02:30 AM
3D printing, DIY Projects, MAKE Projects, Robotics, Toolbox | Permalink | Comments (10) | Suggest a Site

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