54 DESIGNERS GUIDE TO RELIABLE
OSCILLATORS AND TIMERS
Understanding and designing with the
ever-useful CMOS timer.
■ By Norm Looper
60 ACCESS SERIAL PORTS WITH
VISUAL BASIC .NET
Say you have a microcontroller circuit
that needs to talk to a PC. A serial port
is perfect for this type of application.
But what if your computer doesn’t
have a serial port? No problem! Visual
Basic lets you access USB/serial port
adapters and virtual serial ports.
■ By Jan Axelson
67 HOW TO TRICK AN OP-AMP
Operate an op-amp on a single polarity
supply, even though it wants to see both
a positive and a negative voltage.
■ By Richard Schroeder
74 TAMING WALL WARTS
Lurking around your home are devices
that are constantly drawing current
unbeknownst to you that result in
needless power drain. Don’t be alarmed!
There are some things you can do to
minimize this waste of energy.
■ By Kenton Chun
10 READER FEEDBACK
30 NEW PRODUCTS
12 TECHKNOWLEDGEY 2008
Events, Advances, and News
Bionic lenses, Navy railguns,
peewee PCs, and switches without
moving parts are just a few of the
16 PERSONAL ROBOTICS
Understanding, Designing & Constructing Robots
A preview of the new
Reader Questions Answered Here
Bird feeding monitor, eight bit
binary counter, low battery cut-off
77 THE DESIGN CYCLE
Advanced Techniques for Design Engineers
Welcome to the land of CPLD.
84 OPEN COMMUNICATION
The Latestin Networking and Wireless Technologies
Wi-Fi makes Internet radio wireless.
88 PICAXE PRIMER
Sharpening Your Tools of Creativity
Getting started with stripboard
April 2008 7