All posts by Windell Oskay

About Windell Oskay

Co-founder of Evil Mad Scientist Laboratories.

Book review: Sticker Nation by Srini Kumar

Sticker Nation - 1

For years we’ve admired the brilliant stickers, buttons, and shirts produced by Unamerican Activities (“quality rebellion at affordable prices”). So, when we came across a whole book about the stickers for $15 at Amazonwe though it was pretty sweet.
But what really sealed the deal was that we realized that it wasn’t just a book about the stickers but a book of stickers— 432 sweet stickers for fifteen bucks.
Continue reading Book review: Sticker Nation by Srini Kumar

Evil Little Garage Sale

kingbright

I have some excess 16-segment displays, and people keep asking me where to get these. So… you can get them from me for the moment. This is a Kingbright PSA08-11HWA, a red 16-segment single-character alphanumeric LED display. It has a 20mm ( 0.8 inch) character height and a common-anode drive configuration. It’s the same one that I used for the micro-readerboard holiday ornaments as well as for our logo.

I have two unopened (new, old stock) tubes of 18 pieces each, 36 pieces total. These are getting difficult to find. But, until I run out, I’m selling the displays for $2 each plus $1 per order for shipping (US only), payment via paypal. If you’d like to buy some or all of them, E-mail me.

Update: Poof! We’re sold out. (And wow, that was fast!)

 

Sneak preview: The Evil Mad Scientist 3D Printer Project

X & Y Axes

Did you enjoy making sugar cube sculptures as a kid? Boy have we got a project for you.
Besides the projects that we post here each week, we’ve been working on some larger scale projects in the past year. One of these is almost done, and we’re ready to give you a sneak preview: It’s a home-built, DIY, CNC, 3D printer, that uses granulated sugar as the printing medium. This is still a work in progress, but we’re making rapid progress and we hope to show off the completed printer at the Bay Area Maker Faire in May.

(Update added 5/9/2007: we’ve got it working now.)

The printable volume is 24 x 13.5 x 9 inches, with programmed resolution of 1000 steps per axis. We expect effective pixel size to be in the range of 2-5 mm. In other words, it makes fairly large, but fairly low resolution, models out of sugar. Think of it as a way to make giant and amazing sugar cube sculptures!
Continue reading Sneak preview: The Evil Mad Scientist 3D Printer Project

Quick and Dirty D to A on the AVR: A timer tutorial

So you’ve got a microcontroller and you want to use it to control something analog. That’s a common task, and a number of good solutions exist, depending on exactly what you need to do.
Most microcontrollers do not include built-in digital-to-analog conversion (DAC) hardware, and external converters cost money. There is, however, a quick, easy, and cheap little trick of a solution that can be played by averaging a digital output.
This is a short tutorial on making useful (but crude) analog output signals with a low-cost microcontroller. The analog signals will be made by averaging a digital pulse width modulation (PWM) output from one of the counter/timer units in the microcontroller, and do not require any dedicated digital to analog conversion hardware. We will first introduce some aspects of the counter/timer and discuss how it can be used to generate the pulse width modulation signal. After that, we’ll implement the scheme on an AVR microcontroller and use it to make a simple and slow little function generator circuit.

Continue reading Quick and Dirty D to A on the AVR: A timer tutorial

LED Matrix Displays

Big and little LED matrix displays

Mike Kash, my physics professor at Lake Forest College, once said that he liked matrices “so much that I sleep on one.” The two
5×7 LED matrix displays shown here have pointy plastic edges and are probably not very comfortable to sleep on.

These displays are both alike in character, with the same potential to display thirty five beautiful and well-resolved pixels of bitmappy goodness. That’s just the thing for the new video standard that I’m proposing: Widescreen Ultra Low Defintion, or WULD for short. (HDTV is for wimps. 128-bit video may spark a format war with WULD, but widescreen it is not.)

It is fun to contrast the remarkably different sizes of these two displays. The one on the left is from a large readerboard, and is four inches tall with 10 mm green LEDs. The dots are almost as big as the entire miniature version, shown on the right with its 3 mm red LEDs. More common than either of these sizes are the two-inch 5×7 displays that populate the readerboards sold at office supply stores.

LabVIEW routines for the MAKE Controller

MakeController

As evidenced by a growing collection of projects, the MAKE Controller has great potential as a hardware platform enabling computers to really do things.

We won a MAKE Controller for our set of Halloween projects this year, and we’re just starting to play around with it. Having spent some pondering how best to communicate with the board, it’s clear that one of the barriers to more widespread use of this and other embedded systems is the lack, or perceived lack at least, of user-friendly software for programming and communication.

A number of open-source software packages, such as processing and Ruby, can communicate with the MAKE Controller using its OSC interface. However, there has been a noticeable absence of a suitable interface to LabVIEW, a program that is commonly used for interfacing to other similar types of hardware.

So, we wrote one. It’s a simple LabVIEW “vi” routine for issuing (most) simple commands and queries to the MAKE controller. We’ve also included some example routines to help you get your blinky lights going a few minutes sooner.
Continue reading LabVIEW routines for the MAKE Controller

Futility pole


Futility pole

What is a utility pole that has no utility? Apparently it doesn’t just cease to exist. This old telephone pole is simply bare, waiting, hoping, that someday it will be put to good use.

Is that an antenna in the middle? Nope– it’s on the house behind the trees. Futility indeed.