Circuit Cellar Ink 231
October 2009

Table of Contents


CJ Abate

HTML Task Manager

Signal Significance


John Gorsky

HTML New Product News


Naubert Aparicio

IR Signal Control

Do you want offsite control of your electronic equipment? With this handy IR signal controller design, you can remotely operate the system of your choice from your cell phone. In this project, the innovative design is used to control an AC system.



Arnold Stadlin

Frequency Sensing Made Simple

Power Grid Frequency Monitor Design

This power frequency monitor indicates the relative stability of a power grid. Built around a microcontroller, a precision crystal oscillator, an op-amp and various passive components, the design measures power grid frequency via a standard electrical outlet. It then sends the data to a PC, displays the information, and relays it to a web server for real-time monitoring.


Above the Ground Plane


Ed Nisley

Capacitor ESR Measurement

Most commonly available instruments don't measure equivalent series resistance (ESR). Inspired by the design of a classic pure-analog ESR meter he studied on the Internet, Ed recently built an analog front end for an MCU that measures ESR. In this article he describes the design and the math associated with the project.



George Anderson

Digitally Controlled Amplifier

Connect Vintage Analog to Modern Digital Tech

The dsPIC30F2023-controlled MiniTron is a high-end vacuum tube stereo amplifier with distortion control, power output and more. The fully-functional amplifier successfully blends its unique circuitry and specialized processing software to precisely match the radically different worlds of high-voltage analog and low-voltage microcontrollers.


The Darker Side


Robert Lacoste

Multirate Techniques and CIC Filters

Cascaded integrator-comb (CIC) filters are specific forms of moving-average filters that enable you to tackle difficult signal-processing problems. With these filters and some helpful multirate signal-processing techniques, you have another option when a FIR filter doesn't fit the bill.


From the Bench


Jeff Bachiochi

Airflow Analysis

Do you need a way to measure airflow in an air duct? Try deconstructing a small CPU fan, calculating the RPMs, and putting together a circuit to output data to an LCD. Airflow analysis made simple.


Silicon Update


Tom Cantrell

Thumbs Up

The ARM Saga Continues

It's been more than two decades since Acorn Computers introduced its RISC CPU. The saga continues with the latest chapter in the ARM story, the ARM Cortex-M0 core.


Crossword Puzzle


Advertiser's Index / November Preview


Steve Ciarcia

HTML Priority Interrupt

A Broadening Experience

Bonus Article


Sitti Amarittapark

Buddy Memory Manager

When memory matters but you don't have the proper support for dynamic memory management, you may find the Buddy Memory principle to be the perfect solution. This article covers a useful memory management library based on the Buddy Memory principle. With a thorough understanding of the principle, you'll be able to put the library to good use.


Bonus Article


Mahesh Venkitachalam

Arduino-Based Temperature Display

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