Circuit Cellar Ink 140
March 2002

Table of Contents


Rob Walker

Task Manager

Fun, Games, and Inside Information


John Gorsky

HTML New Product News

  • MCP602x family of low-current opamps from Microchip Technology, Inc.
  • ADS1218 24-bit ADC with flash memory from Texas Instruments
  • CDS-1375 LCD and touchscreen controller from Apollo Display Technologies, LLC
  • Ep11E9 development board for 68HC11E9 from


David Tweed

HTML Test Your EQ


Michael Collier, Ph.D.

A PIC-Based Portable ID Reader for iButtons

We've seen home security applications for the Dallas iButton, but the practicality of the technology makes it a good candidate for a campus security system too. Designed for an African university, this project provides a cost-effective reader for the iButton security system.


Brian Millier

High-Resolution Data Acquisition Made Easy

On our workbenches, there's a good amount of analytical equipment that lacks a PC for control or data acquisition. That's not to say that this hardware is obsolete, it just needs updating. Retrofitting hardware can be a fun and cost-effective alternative to replacement.



Tom Petruzzelli

A Web Link Monitoring System

Based on a Basic Stamp II processor and a mini web server module, Tom's web link system provides a flexible monitoring system that can be configured for a variety of applications and sensors. The alarm capabilities make it useful in nearly any situation.



Praveen P. Deshpande
Prajakta Deshpande

In-Circuit Emulator for the AT89Cx051 Family

After developing a surgical laser controller, Praveen and Prajakta received a request to move the power controls from the front panel of the unit to the laser tip. They decided that an emulator would be a good tool to have to make the necessary changes, so they built one.



Mariano Barrón
Javier Martinez

Balancing D/A Conversion on One Pin

If you've ever thought it would be nice to generate an analog output from an MCU without PWM outputs, you're not alone. Mariano and Javier have already done the homework and come up with the software that allows for just such a beneficial convenience.

Embedded PC


Fred Eady

HTML Applied PCs

Replacing Relays with Ladder Logic, Part 1: Getting Ready for the Climb

Fred's reaching for the sky with his latest project so it's no surprise that ladder logic came into play. With a well-balanced programmable logic controller board, Fred observed the "Do not disturb" labels on the board and tried figuring out the hardware via the software.


Jeff Bachiochi

HTML From the Bench

Spy-Size Event Logger

When it comes to performing a time study or logging events, the more information you can gather, the better. Jeff set out to build a small event logger to track events during the off/on cycles of his water pump.



Tom Cantrell

Silicon Update

SoC Hop, The Sequel

When Tom took a first look at the TE505 from Triscend, he liked what he saw. Now, he's following up to let us know how things have come along and what we can expect from Triscend in the future.



Advertiser's Index / April Preview


Steve Ciarcia

HTML, HTML Priority Interrupt

Automobiles by Microsoft?

Circuit Cellar Online

Dariusz Caban

PDF HTML Software Implementation of the I2C Protocol

Thanks to the possibility of all-software implementation of the I2C protocol, microcontrollers can communicate with I2C devices. With this article, Dariusz presents us with an example implementation of the Standard mode of the I2C protocol for the popular 8031 microcontroller.

Download: c0302dccode.ZIP

Circuit Cellar Online

Aubrey Kagan

PDF HTML Do You Excel in Electronics?

Part 3: The Bottom Line

This month, Aubrey concludes his series on Excel by looking at the Solver function, which allows models to be solved using several variables. As an added benefit, he includes a description on the use of regression, and shows us how to look at both linear and quadratic relationships and how the technique can be extended. Join him in this final segment of his series, which has provided insight to the available functions and shown us how to use them.

Circuit Cellar Online

James Antonakos

PDF HTML Ethernet Technology

Part 1: Frames, Collisions, and 10-Mbps LANs

This month, James jump-starts us with a new series on the popular LAN technology, Ethernet. In this first part, he concentrates on the basics, examining all the different Ethernet specifications. But, the story doesn't end there. In the next two parts, he'll also take us through the Fast and Gigabit Ethernet technologies, then round out the series with a look at the operation of hubs, switches, and routers.

Circuit Cellar Online

George Martin

PDF HTML Lessons from the Trenches

Expanding Your Horizons, Using CAD Mechanical Software in Design Projects

The end of every year, brings the end to many projects for George. So, with this expected slowdown, he fills his time with smaller, more unusual projects. One such project, this year, was an industrial packaging project, which gave him the chance to use the mechanical CAD software he'd had lying around awhile.

Circuit Cellar Online

Tom Cantrell

PDF HTML Silicon Update Online

The Dust Flies

With each passing day, it seems the connection between what goes on in the classrooms of higher education and the real world gets harder to distinguish. Although Tom understands the necessity of fundamental research and development, he's lost on how some of their endeavors really benefit the average engineer. Take a walk with him through those hallowed halls, and see if you can't find something that's less like homework and more like fun.

Circuit Cellar Online

David Tweed

HTML What's Your Engineering Quotient?

Test Your EQ presents some basic engineering problems for you to test your engineering quotient.

Circuit Cellar Online

Jenn Belmonte

Resource Links

Each month Circuit Cellar's Resource Links provide helpful links and information on a variety of featured topics.

Circuit Cellar Online

John Gorsky

New Product News

New Product submissions may be sent to John Gorsky, 4 Park St., Vernon, CT 06066.
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