"Evil Mad Scientist Laboratories" - 5 new articles
Typographic Character Coasters
A simple design project for font lovers: Single-character typographic coasters.
We started this project looking at some of the interesting variations amongst common fonts. Blowing them up to this size lets you start to see those differences more clearly than usual. Cutting them out as tangible forms takes it a step further-- you can feel the curves. Also, they make pretty good coasters. The coasters above were laser cut from 1/8" thick cork. The fonts represented include Times New Roman, Gill Sans, Courier New Bold, Futura Bold Italic, and Miso. We picked characters that seemed appropriate for making into single-piece coasters, and scaled them to size, assuming a 3" diameter glass could be placed on top. For the caret, that meant a larger font size than for the octothorpe.
The 1/8" cork sheets are from McMaster-Carr (9487K3), and are relatively inexpensive. They cut well with a hobby knife if you have a steady hand. As we've mentioned before, these days it is straightforward to get parts laser cut for you. Local laser cutting shops are becoming more common and online services like Ponoko and Pololu make it easy to run small projects like these.
Here's a larger set fabbed out of 6 mm hardwood plywood.
Besides plywood and cork, we also made coasters out of medium-density fiberboard (MDF). Both MDF and plywood are susceptible to moisture damage (an operational hazard for coasters!) so we sprayed them with a clear acrylic coating to make them water resistant.
Here are the coasters cut from 6 mm MDF. Interestingly, this material darkened considerably from its "natural" color once we added the clear coat. Some chemistry going on here... not sure what.
Another set, laser cut out of 3 mm white acrylic.
Mmmmmmm.... Curvy. Linkdump: November 2009
YOU HAVE EIGHT EARTH MINUTES LEFTOkay, maybe that's a bit of an exaggeration. But, the deadline for our Arduino Contest at Instructables is approaching right fast: Entries are accepted until this Sunday, Nov 15, 2009, at 11:59 PM PST. Why enter? To show off your cool stuff! Also, you could win a Meggy Jr RGB handheld gaming kit, or an Arduino Mega or other nice goodies, so don't you want to come out and play? Official contest rules are here. The basic entry requirement is that you make a project that involves the Arduino IDE in some way, and you can already check out many of the great projects entered. Woo! Refining Edge-Lit Holiday Cards
We've picked up a bunch of improvements on our Edge-Lit Holiday Cards since last year and we've collected them here for you to see. (Also, welcome Popular Science readers! This project is mentioned in the December 2009 issue.)
We've settled on 1/16" PETG polyester for this project. It is the right thickness for use with a 3 mm LED, and not so thick as to be unreasonable for a card. The polyester has a couple of advantages over the acrylic we used last year. It is soft enough to be indented with a push pin and is still optically clear. It is also inexpensive. (Part 85815K11 at McMaster-Carr is only $2 for a square foot.) With care, it can be cut by hand with heavy duty scissors into rectangles about 2 1/2 to 3" on each side, which will fit into a card made by folding a letter sized sheet of paper (heavy weight paper or cardstock is best) in quarters. Polyester sheets typically ship with a protective film on both sides (you can see that it makes the plastic look opaque in the photo above). You'll want to peel it off before you get started with your design.
We previously used a hobby knife to carve the plastic, but a pushpin can be used to make just about any pattern. Not that we've stopped liking hobby knives, but pushpins do work well and might be more suitable for kids who want to do this project. You can work from a hand-drawn design, or something computer generated. When we released SymmetriSketch this summer, we also updated our Vector Snowflake Application, which is a great way to create a card design. Just print out your snowflake at the right scale and tape it to your plastic.
Press your pin in repeatedly around the edge of your pattern. You can flip it over to check and make sure your marks are getting through.
Once your pattern is complete, peel off your paper pattern. Next you'll need to tape over the edges of the plastic with electrical tape to prevent light leaks.
A piece of black construction paper behind the plastic will help provide contrast when the card is lit. The scratched side of the plastic should be against the black paper, and the smooth side toward the viewer. You'll need a window in your card paper as well, just a bit bigger than your design, but small enough to hide the taped edges of the plastic. For our LED setup, we're still using the classic "LED Throwie" arrangement-- an ultrabright LED is attached directly to the leads of a CR2032 lithium coin cell. When the bright LED is pointed at the edge of the plastic, it travels through cleanly but lights up the areas that we've scratched. 3 mm clear lens LEDs are ideal for this since they work well with the plastic thickness; they transmit lots of light through the edge of the plastic. We recently did some throwie analysis which suggests that if you're going to use red, yellow or yellow-green LEDs, you may want to add a resistor to the circuit in order to extend the battery life. Blue, white, and pure green LEDs work very well driven straight off of the CR2032.
Another way to save the battery is to deliver the card with an "on" switch. A piece of freezer paper can be folded so that the slick side goes between the lead of the LED and the side of the battery. It can be pulled out by the recipient when they get it.
That's it!
If you make your own edge-lit cards, we'd love to see pictures in the Evil Mad Science Auxiliary! New LED Hanukkah Menorah Kit
One of our first kit projects, and one of the consistently most popular, has been the LED Mini Menorah project. For a couple years now we have meant to revisit that project, and we've finally got around to doing so. Here is the result: our new Deluxe LED Menorah Kit.
The circuit board in the new kit sits on an elegant laser-cut stand that incorporates the battery box. It's five inches wide and between 2.75 and 4.25" tall, depending on configuration.
If the circuit board itself looks familiar, you might recognize that this is the "ix" board ("Roman for the number nine...") which we also used on the Larson Scanner project. Phrased another way, this answers the question about why the Larson Scanner kit has nine LEDs. This is an open-source hardware project. The schematic diagram is here and you can find additional design files linked from the Larson Scanner project page.
The kit can be built either with the shamash (lighter candle) in the center or on the side. The default configuration is centered. If you want it on the right-hand side instead, you can solder a wire across jumper location "opt 1" on the circuit board. The button on the board advances between nights, lighting the LEDs in the proper order. There are low and high power modes, for better battery life or brightness. You can switch between them by holding the button for a few seconds. Fades and dimming are done with 64 levels of gray, essentially flicker free due to its high refresh rate.
The source code is available for download here (12 kB .zip file). It's designed for use with AVR-GCC and an AVR ISP programmer. If you're new to AVR programming and want to hack the menorah, add some function to the serial port or so on, you might want to start by looking at our list of resources for getting started with AVR microcontrollers.
Got projects based on this board to show off? We'd love to see your pictures in the Evil Mad Science Auxiliary. More Recent Articles |
