In our past reader surveys, many of you have said you hold onto our old issues. This Signal Processing issue will make a great addition to your reference library. We have an impressive lineup of articles this month featuring a wide range of applications.

In “The Engineer’s Alarm Clock: Design a PIC-Based Lamp Controller,” Aaron Dahlen describes the first of two innovative lamp controller projects in this issue (p. 18). Aaron built a lamp controller that gradually brightens a 120-VAC incandescent light bulb. This unique Microchip PIC18F252-based system simulates the natural sunrise, which Aaron finds particularly helpful on dark winter mornings. For convenience, he designed the system to be controlled remotely. Furthermore, using an infrared remote control enabled him to simplify the user interface, making this project a snap to build.

Stefan Kalbermatter designed an effective lighting control system using the FT232BM USB-to-serial converter chip from Future Technology Devices International (p. 72). With the FT232BM, Stefan was able to build an inexpensive USB-to-DMX-512 converter that enables him to work from his laptop. The mobile system can control eight 230-V, 2-kW channels connected to halogen floodlights. In this article, Stefan covers the basics of the DMX-512 protocol and walks us through his design process.

On page 54, you’ll find another useful laptop project. Using Texas Instruments components, columnist Jeff Bachiochi built a four-port hub designed to enhance the productivity of his laptop that has just one USB port. This power-saving system enables him to connect a printer, digital camera, or joystick in addition to the mouse he ordinarily uses.

Brian Millier takes us out of the field and into the lab. If you’ve been wondering what your workbench has been missing, look no further than the Zilog Z8 Encore!-based Multilab. Brian’s latest design combines an arbitrary function generator, a digital pulse generator, a high-resolution DC voltmeter, and a DC reference source to create an extremely useful multipurpose piece of test equipment (p. 46). He used a PDA for control so that he could minimize the size and cost of the instrument.

Cutting cost is an essential part of most of the projects that we feature, including the sound-effect system developed by Praveen Deshpande and Prajakta Deshpande (p. 62). Their Intel MCS-51 microcontroller-based system generates musical sounds for the digital clock they designed. After you’ve read this thorough article, you’ll be ready to make your own microcontroller-driven sound effects.

I also wanted to draw your attention to one other excellent project we have this month. While designing a variable frequency drive to control three-phase AC motors, Armando Rosas Morato and Sergio Elizarraras Rodriguez developed a scheme for unipolar sine wave pulse-width modulation (p. 32). In their article, “An SPWM Calculator: Using the Switched Integration Technique,” they discuss their high-performance quadrature SPWM modulation technique, or QUSPWM. The QUSPWM algorithm, written in MATLAB by MathWorks, is an effective tool for analysis.

I regret to report that Sergio lost his battle with cancer six weeks before this article was published. All of us here at Circuit Cellar send our condolences to Armando, his coauthor and friend.

jennifer.huber@circuitcellar.com