 In the new edition of the Arduino Cookbook, Michael Margolis gives a great step-by-step explanation of how to read a schematic and build a breadboard prototype from it. The following excerpt is adapted from Appendix B of the Cookbook. Using Schematic Diagrams  A schematic diagram, also called a circuit diagram, is the standard way of describing the components and connections in an electronic circuit. It uses iconic symbols to represent components, with lines representing the connections between the components. A circuit diagram represents the connections of a circuit, but it is not a drawing of the actual physical layout. Although you may initially find that drawings and photos of the physical wiring can be easier to understand than a schematic, in a complicated circuit it can be difficult to clearly see where each wire gets connected. Circuit diagrams are like maps. They have conventions that help you to orient yourself once you become familiar with their style and symbols. For example, inputs are usually to the left, outputs to the right; 0V or ground connections are usually shown at the bottom of simple circuits, the power at the top. Here are some of the most common components, and the symbols used for them in circuit diagrams:
 Here is a schematic diagram that illustrates the symbols used in a typical diagram:  Components such as the resistor and capacitor used here are not polarized—they can be connected either way around. Transistors, diodes, and integrated circuits are polarized, so it is important that you identify each lead and connect it according to the diagram. This drawing shows how the wiring could look when connected using a breadboard:  The finished breadboard illustrations were produced using a tool called Fritzing that enables the drawing of electronic circuits. Wiring a working breadboard from a circuit diagram is easy if you break the task into individual steps. The next illustration shows how each step of breadboard construction is related to the circuit diagram.   The finished circuit is from Recipe 1.6 in the Cookbook, which produces a sound that is controlled by a light dependent resistor. More:

Nina Arens, museum specialist, wrote up this piece for the Mini Maker Faire Seattle blog, and I wanted you all to see it! -Willow Designing a booth for Maker Faire may seem like an intimidating project. Festivals like these attract a broad demographic, a lot of questions, and all sorts of people with different interests and objectives. Combine it with the fact that visitors hardly ever linger at an exhibit longer than eight minutes, and it may feel downright impossible. But don’t panic! You are a maker! You CAN make a fun, interactive exhibit! Whether you’re a multimedia artist, a laboratory scientist, a basement tinkerer, or a vendor, every made object can have an interactive element. It may not seem apparent right away, but no matter how complex, all ideas are a built on simple foundations. Design Take-Home Projects from Complex Ideas Imagining just how a visitor could take home a piece of your display can be difficult. Especially if your project is a long process. Or requires special tools. Or an attention span. Here are some ideas to help you do it with a little creativity.  Protein Chains with beads and pipe-cleaners I wanted to convey how a cell makes its proteins to 4th grade girls at Bailey-Gatzert Elementary. Obviously, I couldn’t bring them to my lab, or have them visualize something. And certainly they wouldn’t sit still for a lecture. Instead, I adapted a beading activity to simulate the biological process in similar ways. At my booth, girls worked to thread and fold “pipe-cleaner proteins” using the letters in their names as a recipe.  Give kids a printout to take home. It was an adaptable project that was personable, quick, and had multiple points for entry. The girls had a blast! They built a pipe-cleaner protein for me that I still own. Another great example I’ve seen is a virtual chemistry activity in Scotland during Edinburgh’s 2011 Science Festival. Unable to bring visitors directly into their organic lab, they simulated building a molecule. At their station, kids could digitally built a 3D ball-and-stick molecule, print it, and then view it through 3D glasses. Very cool! I printed a sodium acetate for myself. She also goes into perfect science vs imperfect science, tools and materials, and not forgetting the little ones. You can read the rest at Mini Maker Faire Seattle blog. She wraps up with: If you’re not sure about how you’re going to create a booth for Maker Faire, don’t fret. There are many possibilities out there. And if you’re local, you know your community best. You’ll see. By the time you’re done, you’ll find the next best thing about being a maker is teaching others how they can be makers, too.

 Inspired by gypsy wagons, with a dash of Oregon Trail pioneering, the maker known as Paleotool has submitted “The Vardo” wagon to the Road to Maker Faire Challenge, presented by Esurance. One lucky maker will win $2,000 to bring themselves and their awesome project to Maker Faire Bay Area next month. Paleotool took the title of this challenge to its very literal logical conclusion, proposing a tow-hitched trailer journey to the Bay Area – hah! As a fan of alternative habitats, I’m impressed not only with the build quality, but by how expansive the interior is, with a bed, stove, and plenty of storage space for short-term living. The winner of the Challenge will be announced very soon, but there’s still time to apply – the deadline is April 5th, so apply now for your chance to win $2K!  Ledge box from rear.
 View through the vardo taking shape.
 Interior panorama. See more of “The Vardo” here.

 …breeding projects out of the dead rock, mixing
Portland cement and aggregate, stirring
Dry gravel with spring rain. Or something like that. Anyway, I promise that our materials Skill Builder unit for this month will be much more fun than The Waste Land. As hard as it may be to even imagine that much fun in one place. During April, we are spotlighting one of humanity’s oldest, cheapest, and most commonly-used building materials—also, surprisingly, one of its most poorly understood. Speaking generally, concrete is a mixture of three components: aggregate, cement, and water. The aggregate can be gravel, sand, glass, plastic, chunks of old concrete, or pretty much any other solid filler. Concrete’s characteristic transformation—from wet slurry or paste to hard, rock-like solid—depends on the reaction between cement and water, a chemical process known as hydration. But the number of variables involved in the process of mixing and forming a particular batch of concrete is surprisingly large, and the structure of bulk concrete, at the atomic and molecular level, is wonderfully complex. Scientists are just now beginning to understand it. And while we can’t hope to even touch on every aspect of the subject in a single month, we can, hopefully, show you something you haven’t seen before, and maybe even inspire you to make something concrete, yourself. Stay tuned! P.S. As always, if you’ve seen a project or a maker doing something inspiring with our featured material, please do let us know, below. Thanks!

By George Hart for the Museum of Mathematics Here is a challenging star construction you can make from twelve playing cards. The underlying geometric form is the third stellation of the rhombic dodecahedron. However, there is a twist in this design that makes it somewhat tricky (but fun) to assemble. To make your own copy, cut four slits in each of twelve cards, as indicated by solid lines in the template below. Fold each on the diagonal shown as a dotted line. Try assembling them by connecting long slits to short slits, guided by the image above. No tape or glue is needed; it all locks together when the final piece is inserted. If you give up, you can find detailed instructions here.  More:
Catch up with all of George Hart’s Math Monday columns

  This article from Scientific American describes one of the world’s very first numerically-controlled machine tools, a 3-axis Cincinnati Milling Machine Company “Hydro-Tel” painstakingly adapted for programmable electronic control two years before the first commercial silicon transistors: THE M.I.T. system combines digital and analogue processes under feedback control to govern a milling machine whose cutting tool moves in three planes relative to the work piece. In this case the “model” of the object to be fabricated is supplied to the machine in the form of a perforated paper tape similar to that used in teletype systems. For a typical operation, 10 feet of tape will keep the machine busy for an hour. The components of the M.I.T. system are grouped into two major assemblies. The first of these, called the “machine,” comprises the milling machine itself, the three servo-mechanisms employed to operate its moving parts, and the instruments required to measure the relative positions of these parts. The second assembly, called the “director,” contains all the data-handling equipment needed to interpret the information on the tape and to pass it on as operating commands to the machine. The director contains three major elements: a data-input system, a data-interpreting system and a set of three decoding servo-mechanisms. Just another juicy bite of early Atomic Age history from our pals at Modern Mechanix. [Thanks, Lee!] An Automatic Machine Tool

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