Telephone Projects For The Evil Genius {McGraw Hill .

You will notice that we begin with easier projectsand escalate to more advanced projects as we goalong. Next, Chapter 7 illustrates how to build afax/modem/answering machine protector whichcan save your phone devices from voltage orlightning spikes and strikes. In Chapter 8 wepresent two different types of telephoneamplifiers. One amplifier is a direct connectdevice which will allow you to amplify thetelephone conversation for a group, or forhard-of-hearing elders. The direct amplifier couldalso be used to amplify a telephone ring remotely.The second amplifier uses a phone suction cupwith a wireless connection to the phone to amplifya phone conversation.Chapter 9 illustrates an automatic phonerecorder switch device which will start and stop atape or voice recorder, in order to record phoneconversations around your home or office. Movingon, in Chapter 10, we take a look at a phoneconferencer circuit which will combine two phoneline conversations. Chapter 11 depicts a devicecalled the frustrator, which will make annoyingpeople go away and never call back!IntroductionNext we present four chapters which coverthemes of circuits and projects. Chapter 12illustrates four telephone hold circuits from simplemanual on-hold and music-on-hold circuits totouch-tone-controlled hold circuits and anautomatic music-on-hold project.Chapter 13 discusses telephone ringer circuits. Westart first with a silent cell phone ringer circuit andthen remote ringer circuits, both wired and wirelesstypes. Our final circuit is a ring generator circuitwhich could be used for intercoms or phone testing.Chapter 14 presents phone status circuits andprojects, from in-use detector, to cut phone linedetector; then we move on to single and dual linestatus monitors. We also present a smart phonelight which turns on a room light when the phonerings so you can take a note or move around theroom for a period of time; and finally a phone linemonitor circuit, called the phone line vigilant.xChapter 15 covers telephone and telephone linetesters, from the simple phone device tester tophone line tester and a phone line simulator. Nextwe move on to some intermediate telephoneprojects, such as the automatic telephonetransmitter project in Chapter 16, which willautomatically broadcast a two-way phoneconversation over to an FM radio, using phone-linepower. Chapter 17 shows the reader how to build acomplete modern electronic telephone.Chapter 18 features a fun voice/musictelephone ringer, which you can program toannounce the phone ringing in your own favoriteway. The tollsaver in Chapter 19 is a phonedialer project which can be used to call a localaccess phone number for saving money or can beused for an older person to immediately call aloved one.Chapter 20 presents the infinity bug, which canbe placed on a phone line you wish to monitor.When called silently, the bug will allow you tolisten-in to a remote site for as long as you like.If you operate a CB or ham radio setup,then you will be interested in building the radio/telephone phone patch described in Chapter 21.This circuit will allow you to interface your radioequipment with the telephone line. The phonepatch will permit a person on the phone to talkto a person on the radio.The phone intercom in Chapter 22 will turn thetelephones in your home into an intercom systemthroughout your whole house. The main intercomcontroller is attached to the phone line and power,while an alert module is placed at each phone toform a complete intercom system using your inhouse phone wiring.Chapter 23 presents a speaker-phone projectwhich will allow you to carry on a phoneconversation without using your handset, thusfreeing up your hands for more important tasks.The speaker-phone project will also permit a groupof people to converse on the phone with a personat a distance.

The tattletale project illustrated in Chapter 25was designed to remotely monitor alarm conditionsand report to you via a remote phone call. You willbe able to monitor a remote room or cottage whileyou are away from home or the office.Chapter 26 will show you how to build a DTMFremote phone controller. With this project you candial your home phone and remotely control devicessuch as lights, fans, and air-conditioners.Our next projects feature the use of a smallmicrocontroller called the BASIC STAMP 2.In the remaining projects you will program thecontroller to perform specific telephone controls.Chapter 27 is an introduction to the BASICSTAMP 2 controller. This chapter illustrates varioustypes of BASIC STAMP 2 controllers and howthey work; next we will move on to actualmicrocomputer projects using the BASICSTAMP 2.Chapter 28 will show you how to build atouch-tone generator, as well as a touch-tonedecoder/display unit which will display a phonenumber that was dialed on a phone line or on aradio frequency, e.g., via ham radio.Chapter 29 presents a caller-ID project whichwill display the phone number of persons callingyou, so you can decide if you want to answer thephone or not.The Page-Alert project in Chapter 30 forms asmall local alarm system which pages you in theevent of an alarm condition. You can create yourown multi-sensor alarm to monitor your home oroffice and let the page-alert call you to report analarm condition.The Tele-Alert project in Chapter 31 willpermit you to monitor your home or office withalarm sensors and report an alarm condition toyour cell phone.Finally, Chapter 32 presents a dial-up temperaturealarm system, which will allow you to monitor theremote temperature of your vacation home or cabinin the comfort of your own home. If your creativeinterest has been aroused, you may want to expandthe system to monitor other devices.Telephone Projects for the Evil Genius willopen up a whole new area for electronics projectbuilding fun, projects that both you and yourfamily will find useful and enjoy, and which youcan build at a fraction of the cost of similarcommercial products. A number of projects in thisbook are not commercially available and will neverbe available to the general consumer, but with thisbook you will be able to create any number oftelephone related projects that will save you timeand money as well. Take your time and enjoy thebook; you may even find a project that you cannotlive without!We hope you will find the projects educationaland interesting and that you will want to buildone of these projects to enhance the telephonesystem in your home or office. Have fun andbe safe!xiIntroductionHave you ever wanted your phone conversationto remain private from possible nosy friends,family, or coworkers? Then you will appreciatethe phone scrambler project in Chapter 24, whichwill keep your conversations unintelligible.

AcknowledgmentsA book is a complex entity and requires the helpof many people to see it through to completion.I would like to thank the following people inmaking this book possible. First I would like tothank senior editor Judy Bass, her assistantRebecca Behrens and all the folks at McGraw-HillProfessional who had a part in making this bookpossible. I would like to also like to thank thefollowing people and companies listed below, whohad a part in bringing this book to completion. Ourhope is that the book will encourage readers tobuild the projects and that it might help inspireyoung electronic enthusiasts to enter the fields ofengineering and electronics.Larry Steckler/PoptronixKen Gracey/Parallax, IncThomson PublicationsArthur Seymour/Elenco ElectronicsRamsey ElectronicsCengage LearningFrank Montegari/Glolab, IncBill BowdenDave JohnsonAnthony CaristiTom EngdahlColin Mitchell/Talking ElectronicsRebecca Lowery/Vellemen, IncxiiCopyright 2009 by The McGraw-Hill Companies, Inc. Click here for terms of use.

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Chapter 1Telephone HistoryHe sent charges nearly 300 feet over brass wire andmoistened thread. An electrostatic generator poweredhis experiments, one charge at a time.Telephone comes from the Greek word “tele,” meaningfrom afar, and phone, meaning voice or voiced sound.Generally, a telephone is any device which conveyssound over a distance. Talking produces acousticpressure. A telephone reproduces sound byelectrical means.In 1800, Alessandro Volta produced the first battery.A major development, Volta’s battery providedsustained low-powered electric current at high cost.Chemically based, as all batteries are, the batteryimproved quickly and became the electrical source forfurther experimenting. But while batteries got morereliable, they still could not produce the power neededto work machinery.The dictionary defines the telephone as “an apparatusfor reproducing sound, especially that of the voice,at a great distance, by means of electricity; consistingof transmitting and receiving instruments connected bya line or wire which conveys the electric current.”Electricity operates the telephone and it carriesyour voice.Then in 1820 Danish physicist Christian Oersteddemonstrated electromagnetism, the critical idea neededto develop electrical power and to communicate. In afamous experiment at his University of Copenhagenclassroom, Oersted pushed a compass under a liveelectric wire. This caused its needle to turn frompointing north, as if acted on by a larger magnet.Oersted discovered that an electric current creates amagnetic field.Telephone history begins, perhaps, at the start ofhuman history. Man has always wanted to communicatefrom afar. People have used smoke signals, mirrors,jungle drums, carrier pigeons, and semaphores to get amessage from one point to another. But a phone wassomething new. A real telephone could not be inventeduntil the electrical age began. The electrical principlesrequired to build a telephone were known in 1831 but itwas not until 1854 that Bourseul suggested transmittingspeech electrically. And it was not until 22 years laterin 1876 that the idea became a reality. Telephonedevelopment did not proceed in an organized line likepowered flight, with one inventor after another workingto realize a common goal, rather, it was a series of oftendisconnected events, mostly electrical, some accidental,that made the telephone possible.Around 1821, Michael Faraday reversed Oersted’sexperiment. He got a weak current to flow in a wirerevolving around a permanent magnet. In other words,a magnetic field caused or induced an electric current toflow in a nearby wire. In so doing, Faraday had built theworld’s first electric generator. Mechanical energy couldnow be converted to electrical energy. Faraday workedthrough different electrical problems in the next 10 years,eventually publishing his results on induction in 1831.Probably no means of communication hasrevolutionized the daily lives of ordinary people morethan the telephone. The actual history of the telephonewas long and arduous with many twists and turns and isa subject of complex dispute to this day.Then in 1830 the great American scientist ProfessorJoseph Henry transmitted the first practical electricalsignal. A short time before, Henry had invented the firstefficient electromagnet. He also concluded similarthoughts about induction before Faraday but he did notpublish them first. Henry’s place in electrical historyhowever, has always been secure, in particular forshowing that electromagnetism could do more than createcurrent or pick up heavy weights—it could communicate.The actual telephone was built upon the work ofmany people who preceded Alexander Graham Bell.In 1729, English chemist Stephen Gray is believed to bethe first person to transmit electricity over a wire.1Copyright 2009 by The McGraw-Hill Companies, Inc. Click here for terms of use.

Chapter One: Telephone HistoryIn 1837, Samuel Morse invented the first workabletelegraph, applied for its patent in 1838, and was finallygranted it in 1848. Joseph Henry helped Morse build atelegraph relay or repeater that allowed long distanceoperation. The telegraph later helped unite the countryand eventually the world. In 1832, he heard of Faraday’srecently published work on inductance, and at the sametime was given an electromagnet to ponder over. Anidea came to him and Morse quickly worked out detailsfor his telegraph. His system used a key or switch, tomake or break the electrical circuit, a battery to producepower, a single line joining one telegraph station toanother, and an electromagnetic receiver or sounder thatupon being turned on and off produced a clicking noise.He completed the package by devising the Morse codesystem of dots and dashes. A quick key tap broke thecircuit momentarily, transmitting a short pulse to adistant sounder, interpreted by an operator as a dot.A lengthier break produced a dash. Telegraphy was notaccepted initially but eventually it became big business.In the early 1870s the world still did not have aworking telephone. Inventors focused on telegraphimprovements since the telegraph itself already had aproven market. Developing a telephone, on the otherhand, had no immediate market, if one at all. ElishaGray, Alexander Graham Bell, as well as others suchas Antonio Meucci, and Philip Reis trying to developa multiplexing telegraph—a device to send severalmessages over one wire at once. Such an instrumentwould greatly increase traffic without the telegraphcompany having to build more lines. As it turned out,for both men, the desire to invent one thing turned intoa race to invent something altogether different.In the 1870s, two inventors, Elisha Gray andAlexander Graham Bell, both independently designeddevices that could transmit speech electrically, thedevice destined to be called the telephone. Both menrushed their respective designs to the patent officewithin hours of each other; Alexander Graham Bellpatented his telephone first. Elisha Gray and AlexanderGraham Bell entered into a famous legal battle over theinvention of the telephone, which Bell eventually won.The principle of the telephone was uncovered in1874, but it was the unique combination of electricityand voice that led to Bell’s actual invention of thetelephone in 1876. Bell’s original telephone is shown inFigure 1-1. Convincing Bell’s partners, Gardiner GreeneHubbard, a prominent lawyer from Boston, and ThomasSanders, a leather merchant with capital from Salem,about the potential for voice transmittal was not an easytask, and they often threatened to pull Bell’s funding.Nonetheless, agreement was finally reached and the trioreceived U.S. Patent No. 174,465, issued on March 3,1876, for “Improvements in Telegraphy,” which is nowconsidered to be the most valuable patent ever issued.Bell’s experiments with his assistant Thomas Watsonfinally proved successful on March 10, 1876, when theThe telegraph and telephone are both wire-basedelectrical systems, and Alexander Graham Bell’s successwith the telephone came as a direct result of his attemptsto improve the telegraph. When Bell began experimentingwith electrical signals, the telegraph had been anestablished means of communication for some 30 years.Bell developed new and original ideas but did so bybuilding on older ideas and developments. Hesucceeded specifically because he understood acoustics,the study of sound, and something about electricity.Other inventors knew electricity well but little ofacoustics. The telephone is a shared accomplishmentamong many pioneers, therefore, although the credit andrewards were not shared equally.2Figure 1-1 Bell’s first telephone instrument

Bell considered his invention’s greatest advantage overevery other form of electrical apparatus to be the fact thatit could be used by anyone, as “all other telegraphicmachines produce signals which require to be translatedby experts, and such instruments are therefore extremelylimited in their application, but the telephone actuallyspeaks, and for this reason it can be utilized for nearlyevery purpose for which speech is employed.”Bell was nearly beaten to the patent office by ElishaGray, who had independently developed a very similarinvention. Gray arrived just hours after Bell at the PatentOffice, filing a “caveat,” a confidential report of aninvention that was not yet perfected. Western Electric,co-founded by Gray, became one of the Bell System’smajor competitors. Western Union was another majorcompetitor, already having established itself as acommunications provider with the telegraph system.In 1877, construction of the first regular telephoneline from Boston to Somerville, Massachusetts, wascompleted, a distance of three miles. Commercialtelephone service began in the United States in 1877.The workable exchange, developed in 1878, enabledcalls to be switched among any number of subscribersrather than requiring direct lines. Exchanges werehandled manually, first by boys, then by the nowfamous women operators.By the end of 1880, there were 47,900 telephones inthe United States. The following year telephone servicebetween Boston and Providence had been established.Service between New York and Chicago started in1892, and between New York and Boston in 1894.Transcontinental service by overhead wire was notinaugurated until 1915. The first switchboard was set upin Boston in 1877. On January 17, 1882, Leroy Firmanreceived the first patent for a telephone switchboard.The first regular telephone exchange was establishedin New Haven in 1878. Early telephones were leased inpairs to subscribers. The subscriber was required to putup his own line to connect with another.In 1889, Almon B. Strowger, a Kansas Cityundertaker, invented a switch that could connect oneline to any of 100 lines by using relays and sliders.This step by step switch used to receive the dial pulsesbecame known as “The Strowger Switch” after itsinventor and was still in use in some telephone officeswell over 100 years later. Almon Strowger was issueda patent on March 11, 1891, for the first automatictelephone exchange. The first exchange using theStrowger switch was opened in La Porte, Indiana, in1892 and initially subscribers had a button on theirtelephone to produce the required number of pulsesby tapping.Strowger installed his automatic exchanges in theUnited States and Europe. In 1924, the Bell TelephoneSystem decided that using operators was not the way togo, and they licensed Strowger’s technology.An associate of Strowger invented the rotary dial in1896 and this replaced the button. In 1943, Philadelphiawas the last major area to give up dual service (rotaryand button).In 1879, telephone subscribers began to be designatedby numbers rather than names—as a result of anepidemic of measles. A doctor from Lowell,Massachusetts, concerned about the inability ofreplacement exchange operators to put calls throughbecause they would not be familiar with the namesassociated with all the jacks on the switchboards,suggested the alpha-numeric system of identifyingcustomers by a two-letter and five-digit system.Long-distance telephone service was established andgrew in the 1880s using metallic circuits. The commonbattery system, developed by Hammond V. Hayesin 1888, permitted a central battery to supply alltelephones on an exchange with power, rather thanrelying upon each unit’s own troublesome battery.A young inventor, Dr. Lee De Forest, began work in1906 on applying what was known as an “Audion,” athree-element vacuum tube, which could amplify radiowaves. He recognized the potential for installingAudions, which became the major component in whatwould be called repeaters on telephone lines, in order toamplify the sound waves at mid-points along the wires.The Bell System bought the rights to De Forest’spatents in 1913. Long-distance telephone service wasconstructed on the New York to San Francisco circuitusing loading coils and repeaters.American Telephone and Telegraph (AT&T) tookcontrol of the Western Union Telegraph Company in a“hostile takeover,” in 1911, having purchased the WesternUnion stocks through a subsidiary. The two eve

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