Electronic-Geek.comYour Electronic Source
|
|
My Make: Projects – Bottle cutting post has proven to be one of the most popular of the series. So here’s a short follow-up revealing a simple trick I discovered for etching designs on glass bottles using the bottle’s label as a built-in resist.
Read more | Permalink | Comments |
Read more articles in MAKE Projects |
This week’s Flashback, from the pages of MAKE Volume 15, shows how authors Jim Moir and Ken Lange devised a camera setup to auto-trigger photos of the critters who came to visit their backyards in the dead of night. Judging from the multitude of pictures they’ve gathered over the years, there is no shortage of wildlife variety in their neighborhood. Check it out to build your own and see what’s lurking behind your house. You can also still pick up a back issue of Volume 15, the Music issue, over in the Maker Shed.
Caught in the Act
By Jim Moir and Ken Lange
Ever wonder what’s getting into your garage at night, eating your cat food in the backyard, or coming by your tent when you’re camping? Now you can find out. With a digital camera, flash, and triggering mechanism, you’ll be able to see exactly which critters are prowling at 3 a.m.
Although there are some challenges to overcome, we’ve discovered that there are plenty of solutions to develop a remote wildlife photography system that meets your needs and budget. Film cameras were used in the past, but clearly digital cameras bring this hobby to a new level by eliminating the expense, time, and effort that comes with film.
MATERIALS
Digital camera We prefer the Kodak DC-290 and discuss its benefits in this article.
Infrared (IR) detector or motion sensor
Camera flash
Power supply
What Does It Take to Do This?
Our challenge was to choose a camera system that can stay awake for long periods (most shut down after a few minutes to conserve battery power) and to rig a method for sensing the animal and triggering the shutter remotely. We also needed a flash capable of illuminating an area large enough to capture pictures of what tripped the camera. Finally, we needed power reserves big enough to run the camera, the external flash, and the animal-sensing trigger mechanism for several days.
What Camera to Use?
We evaluated the 2 typical camera types — point-and-shoot and SLR — to capture our wildlife images. Both have advantages and disadvantages. Point-and-shoot cameras are inexpensive but need a lot of modifications to work. SLRs have more features but can be pricey.
We chose a third path and used the Kodak DC-290. This modestly priced camera was an excellent choice, with a respectable 3.3-megapixel picture and many programmable features not available in most point-and-shoot cameras. This enabled us to make the system work without extensive hacking, and at the same time kept the total system to a reasonable cost. While this camera is no longer in production, it is regularly available on eBay for $50 to $150 (depending on condition, accessories, and demand).
Read more | Permalink | Comments |
Read more articles in MAKE Projects |
Every chemist (and arguably every scientist, and arguably everyone else in the world), whether amateur or professional, should have an elements collection. Theodore Gray has written eloquently about the hows and wherefores of collecting the chemical elements, so I won’t belabor the point here other than to say: chemistry has been called the central science, and arguably, chemistry’s greatest achievement has been the discovery of the chemical elements, the realization of the periodicity of their properties and its implications for atomic structure, and the isolation of each of those elements in its pure or “standard” state. Collecting the individual elements lets you participate in that incredible story in a way that no amount of book-learnin’ ever will.
Read more | Permalink | Comments |
Read more articles in MAKE Projects |
Photos by Maya Chavez-Akin.
Making ice cream with cryogens stronger than water ice is a fairly common chemistry demonstration stunt. The ideal way to do it is with liquid nitrogen, which is poured directly into the ice cream mixture, with stirring, and causes it to set up in about 10 minutes. Liquid nitrogen, however, can be rather difficult to get your hands on. Most major cities have a supplier that will sell it to you, but very often they have large minimum orders and/or require that you own an expensive dewar flask into which they may safely dispense the liquid nitrogen. At -196 C, liquid nitrogen is also fairly dangerous to handle.
Dry ice is a much more accessible cryogen; it’s available at several major grocery stores in the Austin area, for instance, and I imagine the same is true in other parts of the United States. It sublimes at -78 C, and is thus vastly more effective at freezing stuff than water ice at 0 C. You can make ice cream, just as with liquid nitrogen, by adding dry ice directly to the ice cream mixture. However, because dry ice is frozen carbon dioxide, this procedure results in carbonated ice cream. Which can be quite delicious. But say you don’t want carbonated ice cream?
This procedure borrows from a common technique in the organic chemistry laboratory for cooling reactions to sub-zero temperatures. Instead of using ice water to cool to 0 C, you make a bath of dry ice in some volatile solvent that will not freeze at dry ice’s sublimation temperature of -78 C. Obviously, you can’t use dry ice in water because the water will freeze solid. In the laboratory, acetone and isopropyl alcohol are common coolants. Acetone, however, can be dangerous if handled improperly, and isopropyl alcohol in sufficient quantities to make a large bath can be rather expensive.
I have discovered, however, that denatured ethanol, which is available in hardware stores everywhere, is reasonably priced and makes a good bath with dry ice. Denatured alcohol is also much safer to handle than acetone. Depending on the denaturant, it is also the least toxic of the various hardware-store solvents. In any case, done with reasonable care, this procedure involves no significant risk of contact between the ice cream itself and the coolant. And although denatured alcohol is quite flammable, the dry ice temperature of -78 C is well below its flash point at 13 C, which means that, once the bath is cool, there is no danger of the alcohol vapor igniting from a stray spark. To err on the safe side, however, you should be sure to work in a well-ventilated area.
Read more | Permalink | Comments |
Read more articles in MAKE Projects |
In my Principles of Technology class, we’re using Sketchup to design the parts we will make for the Mendocino Motor. Though we’ll fabricate the parts with hand and power tools, you can also use SketchUp to make the files needed to cut parts on a mill, MakerBot, ShopBot or other CNC tools.
The Mendocino Motor project appears in the Teachers’ Pet Projects section in MAKE, Volume 20, page 79.
Here are some techniques to design parts for the motor:
First get familiar with the SketchUp interface. This is pretty easy; the software is rather intuitive. A good place to start is by making whole shapes with the rectangle and circle tools. Draw a shape, then use the Push/Pull tool to extrude it up or down. You can make a shape on the side of another shape, then pull it out or push it in. Make some shapes. Mouse over the tool icons and you should see the name of the tool in a popup.
You can also do some neat stuff with the Move tool. If you have a cube, draw a line at the midpoints (again, mouse over the lines of your design and watch for the popups). If you pull the line up with the Move tool. This will give you something that looks a lot like a roof of a house on the cube. If you pay attention to the color of the line while you are moving it, you’ll see that it takes on the color of the blue axis if you are pulling straight up. This means that you are moving parallel to the Z or vertical axis.
Read more | Permalink | Comments |
Read more articles in MAKE Projects |
I wrote a couple of weeks ago about the excitement surrounding Clifford Wolf’s new freeware OpenSCAD program. OpenSCAD uses a cool keep-it-super-simple approach to 3D modeling, eliminating the resource-hungry what-you-see-is-what-you-get (WYSIWYG) editing environment favored by most 3D modeling packages, and replacing it with a text-based scripting environment in which models are programmed, instead of sculpted. Basically, you write a script describing your model’s shape and then compile it to produce the actual model, which is then rendered onscreen and can be exported to STL format for 3D printing or other purposes.
OpenSCAD has two powerful features to facilitate this programming processes. The first is support for so-called “constructive solid geometry” (CSG) modeling, in which complex forms are built up as intersections, unions, and differences of simple primary shapes like boxes, cylinders, cones, and ellipsoids. If you’ve ever used the ray-tracing program POV-Ray before, this idea will be familiar to you.
The second, less-well-publicized (but perhaps equally powerful) feature of OpenSCAD is “DXF extrusion,” in which OpenSCAD will import a 2D drawing in AutoCAD’s popular drawing exchange format (DXF) and “extrude” it into the third dimension. OpenSCAD has support for linear extrusion, in which the resulting part has straight vertical sides, and also rotating extrusion, which results in a part with helical sides. Since a large number of models for rapid prototyping are simple extruded profiles, I expect this feature to see a lot of use.
In this tutorial, I’m going to show you how to use OpenSCAD to produce a simple 3D model by extruding a part profile produced in normal drawing software. I use Adobe Illustrator CS3 because I have access to it and am familiar with its interface, but the popular freeware drawing program InkScape will read and write DXF files natively, and there’s no reason why it couldn’t serve just as well if you prefer it. There are a number of other free and low-cost programs that will export DXF files. OpenSCAD’s developer mentions QCAD, which is available from its developer RibbonSoft for €24.
The part I’m making is one of 12 solid pentomino puzzle pieces based on the animals of the Chinese zodiac–in this case, the rabbit or “Z” pentomino. The designs are based on those of Japanese schoolteacher Sabu Oguro as published on p. 40 of Jerry Slocum and Jack Botermans’ 1986 book Puzzles Old & New: How to Make and Solve Them, an image of which is reproduced at the top of this article. My original DXF files and the extruded 3D STL files are freely available for download at Thingiverse. This morning at 10 AM PST, Becky Stern will be streaming live video of her MakerBot CupCake CNC machine printing parts from this set, and she and I will be on-hand to chat about the printing process and the models themselves. Becky printed and photographed all the real-world models shown in this article.
Read more | Permalink | Comments |
Read more articles in MAKE Projects |
It’s been a while since my last build journal, mostly because the finish takes a few days to apply, and yet another few days to fully cure. I’m just happy it’s now done! I want to start building… and printing!
First up, assembling the pulleys. If you purchased a kit, it includes a set of 3D-printed pulleys. This makes the pulleys really easy to assemble. However, there are a few tips and tricks that I’ll cover.
First, make sure there are no extra bits of plastic in the pulley opening. If there are, carefully scrape them off with a hobby knife. Next, use one of the screws from the hardware burrito, along with a nut, to help push the bearing into the pulley. Screw the nut onto the bolt about 1/4″ and then press the bolt head firmly until the bearing is completely seated. It’s a snug fit, but you should be able to press it in fairly easily.
That’s it! All the pulleys are assembled. If you are making your own pulleys from laser cut parts, check out this guide. Now it’s time to apply a finish to your enclosure.
Read more | Permalink | Comments |
Read more articles in MAKE Projects |
This tutorial shows how to take apart a spent zinc-carbon dry cell of the common household type. Besides making for an interesting object lesson in electrochemistry, taking apart a spent D-cell, for instance, allows you to salvage many materials which can be of use to amateur chemists–materials which would otherwise probably end up in a landfill. Separated from their reactive components, the leftover parts of the battery can be safely added to most municipal recycling streams.
A zinc carbon cell (Wikipedia) contains manganese dioxide, which, among other things, is useful as a catalyst in the production of oxygen gas from hydrogen peroxide. It also contains metallic zinc, which can be used, for instance, as a reagent in the production of hydrogen gas from strong acid. Finally, it contains a carbon or graphite rod which can be used as an electrode in any of a number of electrochemical experiments, such as the electrolysis of water and the construction of an arc light or arc furnace.
Note that the battery in this tutorial is a zinc-carbon dry cell. This tutorial does not cover the dismantling of an alkaline-type cell. Alkaline cells are of slightly different internal construction and contain the strong base potassium hydroxide as an electrolyte, which is rather more dangerous to handle than the ammonium chloride/zinc chloride mixture used in zinc carbon cells. Zinc-carbon cells are commonly labelled “general purpose” or “heavy duty,” and will not have the word “alkaline” on the case.
Tools
Materials
Read more | Permalink | Comments |
Read more articles in MAKE Projects |
I planned on writing an entry about burning bootloaders and updating the firmware, but I just realized my kit comes ready to go! Yay! This is a major advantage to purchasing the Generation 3 Electronics kit. If you’re making you own boards, be sure to check out these detailed instructions on burning bootloaders and updating firmware before going any further.
Here’s the description of the Generation 3 Electronics kit [Mostly Assembled]:
This is a kit of mostly assembled electronics. All of the hard stuff is taken care of for you, and the only soldering that remains is the opto endstops which are very simple (only through hole components, no SMT). The stepper drivers, extruder controller, and motherboard all come fully assembled and ready to use. The extruder controller and motherboard have been pre-programmed with the MakerBot firmware and Arduino bootloader.
I know, I know, it’s been a while since my last entry, and I apologize. The truth is, I was a bit under the weather last week, and my CupCake CNC kit had to sit and wait patiently for me to recover. The good news is, I’m feeling much better now and am super motivated to start printing parts! The next entry will be packed with CupCake building goodness. Promise!
Next up, making the pulleys and enclosure. As you can see, I chose a butchers wax finish. It’s nontoxic, and nonflammable, which makes documenting it in my studio a lot easier. Also, it preserves the beauty of the wood, including the laser burns! Besides, if I don’t like it, I can always cut out a new enclosure.
Ask questions! Do you want to see a better picture of a particular part, a different camera angle, a video perhaps? Maybe you have a suggestion for a cool mod or hack? Let me know in the comments. I’ll try to answer them as best as I can. Thanks!
Build history:
Read more | Permalink | Comments |
Read more articles in MAKE Projects |
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:
Materials:
Read more | Permalink | Comments |
Read more articles in MAKE Projects |