Circuit Cellar Ink 227
June 2009

Table of Contents


CJ Abate

HTML Task Manager

Forward-Thinking Designers


John Gorsky

HTML New Product News


Naweed Paya
Venkat Ganesh

Keystroke Communication

Design a Customizable Virtual Keyboard

You can build a customizable virtual keyboard around a microcontroller and some additional affordable parts. This flat keyboard design is the size of a piece of standard paper, which makes it perfect for use at a desk or on an airplane tray table.

Download: Paya_Naweed &

Above the Ground Plane


Ed Nisley

Solar Data Logger

Part 2: Data Points

With a redesigned layout, better power supplies, and a superior inductor, Ed's solar data logger project is back on track. Here he presents the new circuitry and covers the topics of inductor core saturation, PWM filtering (and ripple), and solar panel output.



Robert Bowen

SSI Controller for Linear-Position Sensors

For many applications, retrieving sensor readings requires an SSI controller. But it can be expensive. Robert presents an affordable solution for building your own SSI readout display for position sensors.



Chris Britney
Paul Green
Andy Heath
Stephen Lau
Kylee Lathrop

Autonomous Vehicle Design

Embedded Systems, Sensor Technology, and Motor Control

Autonomous vehicles and mobile applications are becoming increasingly incorporated in the military, industrial, and healthcare industries. This autonomous vehicle design implements the full potential of embedded, sensor, and modular electronic technologies.


The Darker Side


Robert Lacoste

High-Speed Signal Transmission

From Eye Diagrams to Preemphasis and Equalization

When it comes to high-speed signal transmission, there's more than meets the eye. Robert simplifies the topic in this thorough explanation of signal transmission theory. He describes transmission techniques on low-bandwidth cables, and covers the important subjects of preemphasis, equalization, and inter-symbol interference.


From the Bench


Jeff Bachiochi

Location Notification

A Look at Anisotropic Magnetoresistance Sensors

Electronic compasses are an affordable alternative to GPS technology for some embedded designs. After introducing the topic of magnetoresistance, Jeff describes how he used an anisotropic magnetoresistance (AMR) sensor to add navigation capabilities to a recent design.


Silicon Update


Tom Cantrell

Easy (E)mbed

An Alternative Approach to Embedded Programming

Thanks to the march of silicon designing hardware these days is as simple as choosing which of the latest and greatest wunderchipsto use. Ah, but software, well, that's another story. There's no Moore's Law for software and it isn't getting any easier. Maybe it's time for a change.


Crossword Puzzle


Advertiser's Index / July Preview


Steve Ciarcia

HTML Priority Interrupt

Lawns and Ponds

Bonus Article

Michael R. Smith
Lizie Dunling-Smith

Time-Triggered Systems

Part 3: Tackle Data Acquisition

In their last article, Mike and Lizie described how to add a GUI to a cooperative scheduler and then obtain detailed timing information while developing a multitask audio project. Now they present a revised Theremin system design. They also describe how make a co-operative scheduler recover from various data acquisition issues.
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