THE TALKING TELEPHONE
by Steve Sokolowski
Anyone who's ever had the urge to supercharge his home telephone system will welcome author Steve Sokolowski's new book, The Talking Telephone. In it, Steve describes fifteen telephone-enhancement projects ranging in complexity from simple to advanced. Three of the most complicated projects incorporate National Semiconductor's Digi-talker voice synthesizer chips, which are relatively inexpensive ($27) and readily available. One speech project replaces a telephone's bell with a voice that shouts "Hello!" or some other attention-getting phrase. Feeling more ambitious? Well, Steve also presents a circuit that verbally announces the digits you dial, thereby providing immediate confirmation of a correctly dialed number. Such a project would be especially useful to a visually handicapped person. The third and final speech-related project shows how to make the Digitalker speak complete phrases by stringing together words contained in the Digitalker's ROM chips.
Not interested in speech? Well, maybe you'd like to replace your phone's annoying bell with something more soothing and pleasant. Four of the projects do just that. You can take your pick from among an English-style telephone ringer, a two-tone ringer, an electronic ringer, and a melody ringer. The latter is particularly interesting, in that it is based on a chip capable of playing twelve different tunes.
Other worthwhile projects include a phone sentry (which screens out unwanted calls), a flip-flop hold button, and a music-on-hold adapter. Also included are three projects that provide digital displays of the number you've dialed. Though essentially similar, these three projects differ in complexity and the nature of the display they provide. Finally, for anyone who has been trying to stave off the unauthorized use of a telephone, the author presents an ingenious digital telephone lock that will foil even the most determined interloper.
In addition to the main projects just discussed, the book contains a collection of telephone-circuit building blocks which the reader can incorporate into his own designs. These circuits include a surge suppressor, polarity guard, common-ground converter, off-hook detector, ring detector, tone detector, phantom power supply, and universal telephone interface.
Since most readers are apt to know little or nothing about the theory of telephone communication, the author thankfully provides in his first three chapters a detailed introduction to telephone circuits and systems, including digital telephony. He also provides practical construction hints and advice on making printed circuits. (By the way, each project is accompanied by PCB artwork.) All things considered, Steve Sokolowski has done an outstanding job of making the mysteries of the telephone accessible to all of us.
The Talking Telephone, 337 pages, softcover: $16.95, hardcover: $25.95. TAB Book Co., Blue Ridge Summit, PA, 17214-9988. Telephone 1-800-822-8138.
ELECTRICAL WIRING
by Arthur C. Seale, Jr.
You're a typical electronics enthusiast. You've studied circuit theory, you're hip to the fine points of solid-state theory, and your friends all say you're a wizard when it comes to repairing electronic equipment. So there's no reason why you couldn't do the electrical wiring in your own home, right? Perhaps, but remember that for safety's sake, your wiring must conform to the National Electrical Code, and a qualified inspector must verify that it does. You can't just run wires willy-nilly through the walls. So before you start, you'd better bone up on the proper techniques of electrical wiring. To do that, you might want to check out Arthur Seale's new book, which does an excellent job of explaining all aspects of electrical wiring.
The book begins by explaining the nature of the electrical power system, including generation, transmission, and distribution. It progresses to Ohm's Law (easy for you) and such mundane matters as splices (perhaps not so easy, until you've had a bit of practice). The importance of proper grounding is stressed, along with the need for ground fault circuit interrupters (GFCIs) to protect against electrical shocks. We also learn how to set up an electrical service entrance panel.
Since this is a book on electrical wiring, much of the discussion is about wire. We learn how to select the right type and gauge of wire for a particular branch circuit, based upon the anticipated current that the circuit will carry. We also learn about the myriad kinds of electrical hardware available, including conduit, connectors, couplings, and boxes to house switches and outlets. Metallic and non-metallic hardware is available, and we learn where each is best used. The book devotes ample space to the actual business of running wires and making connections. It shows the proper way to use wire-nut connectors and crimp connectors. And we see illustrations of the various kinds of switches and receptacles that are available.
Special attention is given to outdoor home wiring, which must be waterproof, and outdoor security lights, motion detectors, etc. The author even discusses wiring in connection with outdoor pools and hot tubs. The book's coverage extends beyond electrical power per se to include consideration of the wiring associated with security and alarm systems, television antennas, telephones, and cable TV. The book concludes with advice on fishing wires through walls (easier said than done, I'm afraid). To answer the question that was posed at the beginning of this review: Yes, you can do your own electrical wiring, with a minimum of hassle, provided you've done some study in advance, and Arthur Seale's book is an excellent source for the information you'll need.
Electrical Wiring, 274 pages, softcover: $19.95. Howard W. Sams & Co., 11711 N. College Ave., Carmel, IN, 46032. Telephone 1-800-257-5755.
PC POWER PROTECTION
by Mark Waller
The biggest threat to the well-being of your computer is the electrical power that you teed it.
The danger lies not with the 120-volt, 60-Hz sine wave that your power outlet supplies, but with all the garbage that accompanies it.
The switching on and off of motors and other inductive loads impresses high-voltage, short-duration transients on the normal line voltage. Nearby lightning strikes do much the same thing, but with far greater fury. Transient voltages and other power-line aberrations can do two things to your computer: they can destroy it outright, or they can cause it to lose valuable data. Neither outcome is a pleasant one, and so it makes sense to do as much as possible to ensure that power-line aberrations never reach your computer. PC Power Protection offers advice on how to do exactly that.
The book opens with an introduction to basic electrical principles, and then proceeds to document the various kinds of power-line aberrations that can wreak havoc on a computer: impulses, noise, drop-outs, surges, and sags. According to a survey published by IBM in 1972, the typical business can expect an average of two such disturbances per day. Not all of these will be killers, but such statistics point up the need for adequate power protection.
Author Mark Waller goes on to discuss how lightning, motors, and other culprits can induce power-line transients and noise, and how improper electrical grounding in a power-distribution system can exacerbate the deadly effects of these power-line disturbances. He next discusses computer power supplies, both linear and switch-mode, and shows how these two types of supply differ in their susceptibility to transients and noise.
Having established the need for PC power protection, the author proceeds to show how it can be accomplished. Transient suppressors and power-line filters are the cheapest and least effective means of protection, but for the hobbyist who uses his computer only infrequently, they are probably sufficient. The problem with surge suppressors is that, after a sufficiently strong jolt, they may fail-and do so without warning, leaving the user with a false sense of security.
Better protection can be obtained, albeit at a higher price, with a so-called power conditioner, which is essentially a shielded isolation transformer that very effectively eliminates spikes and noise. In the opinion of the author, the power-line conditioner provides all the protection the average user will ever need, particularly if used in conjunction with a surge suppressor. But a power-line conditioner will not protect against the absence of power, which may be either momentary (in which case, it's called a dropout) or long-term (i.e., either a brownout or a blackout). To guard against the loss of voltage, you need an uninterruptible power supply, or UPS. Such a device uses a battery and an inverter to generate AC power for the computer when line voltage is low or absent. The UPS is a worthwhile investment primarily for businesses that use computers.
PC Power Protection, 220 pages, softbound: $19.95. Howard W. Sams & Co., 11711 N. College Ave., Carmel, IN, 46032. Telephone 1-800-257-5755.
SURFACE-MOUNT TECHNOLOGY FOR PC BOARD DESIGN
By James K. Hollomon, Jr.
Electronic devices keep getting smaller and smaller. Today, camcorders fit in the palm of your hand; a television set takes up no more room than a notebook in your shirt pocket. It's a trend we all seem to take for granted, but how is it done? Some off the credit goes to large-scale integration, which packs transistors with ever-increasing density onto IC chips.
But that is just part of the magic. At the board level, a relatively new phenomenon called surface-mount technology has changed the way components are packaged. The new surface-mount packages have leads that are spaced more closely; consequently, the packages themselves are smaller. Furthermore, the leads are no longer inserted into holes in the PC board; instead, they rest flat against the surface of the board, thus allowing components to be mounted on both the top and bottom of the board. The net result of the adoption of surface-mount techniques is to reduce circuit-board area by a much as 60%. James Hollomon's new book is a professional guide to PCB fabrication using surface-mount technology. After reviewing the advantages and disadvantages of surface-mount technology, the author discusses surface-mount components and the new manufacturing methodologies that they demand. New strategies of board layout and design are required, and the author covers these in considerable detail. Quality assurance, always an important consideration in PCB fabrication, gets good coverage too. Specific applications of surface-mount in different types of equipment appear throughout the book, thus giving the reader a feel for what the state of the art is today.
James Hollomon has written a comprehensive, 500-page reference on the techniques of PCB design and manufacture using surface-mount technology. The book is heartily recommended to engineers, manufacturers, and anyone else interested in high-density circuit fabrication. Surface Mount Technology for PC Board Design costs $49.95 and is published by Howard W. Sams, Division of MacMillan Computer Publishing, 11711 North College, Suite 141, Carmel, IN, 46032. Telephone 1-800-257-8247.
IC TIMER COOKBOOK
By Walter G. Jung
The introduction of the 555 timer by Signetics in 1972 was a watershed in the history of circuit design. Although the data sheet said simply that you could use it as a monostable or astable multivibrator, clever engineers soon found dozens of other uses for the device. In fact, it got to be so that you couldn't pick up an issue of Electronic Design or EDN without finding yet another application for the 555 timer. Author Walter Jung has compiled all those diverse applications into one handy reference book.
The book begins with a discussion of timer ICs-not just the venerable 555, but the XR-L555, the ICM7555, the 556, the 558, the 322, the 3905, and the 2240, too. The relevant design equations are presented along with a discussion of circuit operation. After that, we are treated to a whole slew of timer applications-too many for me to list all of them, but here are some highlights: one-shots, ramp generators, square-wave oscillators, time-delay circuits, function generators, burglar alarms, switch debouncers, edge detectors, flashers, tone generators, logic probes, a capacitance meter, a pulse generator, burst generators, and an A/D converter.
Careful descriptions accompany each circuit, making this book useful as a textbook or as a reference.
No technical library is complete without something on timers, and this second edition of the /C Timer Cookbook is as good a reference as you're likely to find. It costs $17.95 and is published by Howard W. Sams, Division of MacMillan Computer Publishing, 11711 North College, Suite 141, Carmel, IN, 46032. Telephone 1-800-257-8247.
DESIGNING, BUILDING & TESTING YOUR OWN SPEAKER SYSTEM, 3rd Ed.
by David B. Weems
Back in the Dark Ages of high fidelity, the fifties and sixties, speaker design was something of a black art, practiced by wizards with names like Kloss, Klipsch, and Bose. Gradually, however, authors like David Weems began to spread the word that speaker design wasn't such a scary thing, and that even amateurs could build their own speaker systems and achieve good results, too.
Today, many people enjoy building their own speaker systems, and it's a safe bet that a goodly percentage of those people got their inspiration from Designing, Building & Testing Your Own Speaker System, a classic that's now in its third edition.
The book begins with a discussion of drivers and their characteristics, such as frequency response, transient response, impedance, compliance, and damping. It then surveys the various types of enclosures currently in use, with particular emphasis on the closed-box (acoustic-suspension) and ported-box (bass-reflex) types, since these are the easiest to design and build. The design approach employed by the author is a graphical one. Once you've chosen a woofer and obtained its resonant frequency, Q, and compliance from the manufacturer's data sheet, you consult a few graphs and charts to find the right internal volume for your enclosure.
You then build a box having the required volume, such that the ratio of depth:width:length equals 0.62:1.0:1.62, or thereabouts. This eliminates unwanted resonance of the air in the box. Choose a compatible tweeter, and perhaps a midrange driver as well, build a crossover network, put it all together and-voila!-you've got a speaker system that sounds as good as a store-bought system costing two or three times as much. Suspicious because it all sounds so easy? Well, don't be. After you've read this book, you'll be building speakers like a pro.
Designing, Building & Testing Your Own Speaker System, 224 pages, softcover: $16.95, hardcover: $24.95. TAB Book Co., Blue Ridge Summit, PA, 17214-9988. Telephone 1-800-822-8138.
INDUSTRIAL ROBOTICS, MACHINE VISION, AND ARTIFICIAL INTELLIGENCE
Ken Stonecipher, Editor
Robotics is a fast-paced, highly innovative field in which ideas deemed revolutionary today may be passe' tomorrow. When progress occurs so rapidly, it is sometimes difficult for workers in the field to keep up with the latest advancements. The book Industrial Robotics, Machine Vision, and Artificial Intelligence was written in an attempt to make the latest research available to newcomers as well as established workers in the field of industrial robotics. It is not a textbook. Rather, it surveys work currently being done in various areas of industrial robotics, and directs the interested reader to books and research papers which further explain the subject. As such, this is a book that will primarily appeal to persons already familiar with robotics and computer science.
Chapter 1 describes the components that make up a robotic system, things like hydraulic actuators, electric motors, pneumatic actuators, and jointed arms
Chapter 2 describes the components of a typical machine-vision system: hardware such as cameras, and software designed to recognize images.
Chapter 3 goes on to describe how two-dimensional images are analyzed, and Chapter 4 does the same for three-dimensional images.
Sensors and their use are covered in Chapter 5. Examples of the application of various sensors in an assembly-line robot are presented. Chapters 6 and 7 discuss artificial intelligence, by which is meant the ability of a machine to emulate human thought-specifically, by making inferences, learning new types of behavior, and recognizing patterns. The final chapter discusses applications of artificial intelligence in manufacturing.
Because the level of presentation is fairly advanced, this is not a book that will appeal to the hobbyist eager to learn about robotics. However, readers with experience in robotics or computer science will come away with a better understanding of how robotics is transforming industry today.
Industrial Robotics, Machine Vision, and Artificial Intelligence, 312 pages, softbound: $39.95.
Howard W. Sams & Co., Division of Macmillan Computer Publishing, 11711 N. College Ave., Carmel, IN, 46032. Telephone 1-800-257-5755.
Also see: Understanding Electricity--Part III
FROM THE EDITOR'S DESK (xv 1994)
adapted from: Electronics Handbook XI (1992)