Design And Implementation Of A Walkie-Talkie

ABSTRACT

This work is on a walkie-talkie, which is a hand-held, portable, two-way radio transceiver. A walkie-talkie is a half-duplex communication device; multiple walkie-talkies use a single radio channel, and only one radio on the channel can transmit at a time, although any number can listen. The transceiver is normally in receive mode; when the user wants to talk he presses a “push-to-talk” (PTT) button that turns off the receiver and turns on the transmitter. Typical walkie-talkies resemble a telephone handset, possibly slightly larger but still a single unit, with an antenna mounted on the top of the unit. Where a phone’s earpiece is only loud enough to be heard by the user, a walkie-talkie’s built-in speaker can be heard by the user and those in the user’s immediate vicinity. Hand-held transceivers may be used to communicate between each other, or to vehicle-mounted or base stations.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• OBJECTIVE OF THE PROJECT
• USES OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• SCOPE OF THE PROJECT
• PROBLEM OF THE PROJECT
• APPLICATION OF THE PROJECT
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

• HISTORICAL BACKGROUND OF THE STUDY
• REVIEW OF CONTEMPORARY USE OF THE STUDY
• REVIEW OF DIFFERENT TYPES OF WALKIE TALKIES

CHAPTER THREE

SYSTEM DESIGN

• DESCRIPTION OF THE SYSTEM BUILDING BLOCK
• SYSTEM BLOCK DIAGRAM
• CIRCUIT DESCRIPTION
• CIRCUIT OPERATION
• SYSTEM COMPONENTS
• HOW TO WIND THE ANTENNA COIL

CHAPTER FOUR

TESTING AND RESULTS

• CONSTRUCTION PROCEDURE AND TESTING
• INSTALLATION OF THE COMPLET DESIGN
• ASSEMBLING OF SECTIONS
• TESTING OF SYSTEM OPERATION
• TROUBLESHOOTING WALKIE TALKIES
• WALKIE TALKIE BATTERIES

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION
• REFERENCES

CHAPTER ONE

1.0                                                        INTRODUCTION

A walkie-talkie is a hand-held, portable, two-way radio transceiver. Typical walkie-talkies resemble a telephone handset, with a speaker built into one end and a microphone in the other (in some devices the speaker also is used as the microphone) and an antenna mounted on the top of the unit. They are held up to the face to talk. A walkie-talkie is a half-duplex communication device; multiple walkie-talkies use a single radio channel, and only one radio on the channel can transmit at a time, although any number can listen. The transceiver is normally in receive mode; when the user wants to talk he presses a “push-to-talk” (PTT) button that turns off the receiver and turns on the transmitter.

1.2                                         BACKGROUND OF THE PROJECT

The walkie talkie, or two-way radio transceiver, had its introduction to the United States in 1939 by Donald L. Hings. Engineers at Motorola helped to pioneer the use of the walkie talkie through World War II. Since its debut, the walkie talkie has had many functions; in business, in play, and with amateur radio enthusiasts. While its popularity has waned in the 21st century, two-way radio transceiver technology remains a focal point of some businesses, and learning how to troubleshoot them can be a vital task.

1.3                                             OBJECTIVE OF THE PROJECT

The objective of this work is to design circuit that can be easily built used for communicating between rooms or floors or from a distance. The range of this system is around 30 meters

1.4                                                   USES OF THE PROJECT

Walkie-talkie radios have many uses. Find more details on some specific applications below:

Using Walkie-Talkie Radios In Schools And Colleges: Walkie Talkie radios can help to solve many problems within school and college campuses. Many members of staff often move around a large site and can be very difficult to track down when they are needed. It is in the nature of the way that schools work that staffs are not desk-based, and there may not be telephones in each class-room etc.

Using Walkie-Talkies In Pubs, Bars, Clubs & Restaurants: Walkie-talkies can be invaluable to enable staff to stay in touch in bars, clubs and restaurants. They are especially useful for security / door supervisors, as well as staff in general.

Using Walkie-Talkies For Skiing, Snowboarding And Other Outdoor Activities: Ski holidays often involve being in areas where mobile phones don’t work – or are incredibly expensive. Our walkie-talkies provide a useful way of staying in touch with your friends while on the slopes. Also useful for other outdoor activities including hiking, cycling etc. Buy them, or hire them to save you money.

Using Walkie-Talkies As A Long-Range Baby Monitor: A pair walkie-talkie radios can be used as a long-range baby listener. With a range far greater than purpose-made baby monitors, they are especially useful when you go on holiday with your family.

1.5                                          APPLICATION OF THE PROJECT

Military

Military organizations use handheld radios for a variety of purposes. Modern units such as the AN/PRC-148 Multiband Inter/Intra Team Radio (MBITR) can communicate on a variety of bands and modulation schemes and include encryption capabilities.

Amateur radio

Walkie-talkies are widely used among amateur radio operators. While converted commercial gear by companies such as Motorola are not uncommon, many companies such as Yaesu, Icom, and Kenwood design models specifically for amateur use. While superficially similar to commercial and personal units (including such things as CTCSS and DCS squelch functions, used primarily to activate amateur radio repeaters), amateur gear usually has a number of features that are not common to other gear, including:

• Wide-band receivers, often including radio scanner functionality, for listening to non-amateur radio bands.
• Multiple bands; while some operate only on specific bands such as 2 meters or 70 cm, others support several UHF and VHF amateur allocations available to the user.
• Since amateur allocations usually are not channelized, the user can dial in any frequency desired in the authorized band.
• Multiple modulation schemes: a few amateur HTs may allow modulation modes other than FM, including AM, SSB, and CW, and digital modes such as radioteletype or PSK31. Some may have TNCs built in to support packet radio data transmission without additional hardware.

A newer addition to the Amateur Radio service is Digital Smart Technology for Amateur Radio or D-STAR. Handheld radios with this technology have several advanced features, including narrower bandwidth, simultaneous voice and messaging, GPS position reporting, and callsign routed radio calls over a wide-ranging international network.

As mentioned, commercial walkie-talkies can sometimes be reprogrammed to operate on amateur frequencies. Amateur radio operators may do this for cost reasons or due to a perception that commercial gear is more solidly constructed or better designed than purpose-built amateur gear.

Personal use

walkie-talkies are also sometimes used as toys because mass-production makes them low cost, they have proper superheterodyne receivers and are a useful communication tool for both business and personal use.

Most personal walkie-talkies sold are designed to operate in UHF allocations, and are designed to be very compact, with buttons for changing channels and other settings on the face of the radio and a short, fixed antenna. Most such units are made of heavy, often brightly colored plastic, though some more expensive units have ruggedized metal or plastic cases.

Recreation

Low-power versions, exempt from licence requirements, are also popular children’s toys such as the Fisher Price Walkie-Talkie for children illustrated in the top image on the right. Prior to the change of CB radio from licensed to “permitted by part” (FCC rules Part 95) status, the typical toy walkie-talkie available in North America was limited to 100 milliwatts of power on transmit and using one or two crystal-controlled channels in the 27 MHz citizens’ band using amplitude modulation (AM) only.

Smartphone apps & connected devices

A variety of mobile apps exist that mimic a walkie-talkie/Push-to-talk style interaction. They are marketed as low-latency, asynchronous communication. The advantages touted over two-way voice calls include: the asynchronous nature not requiring full user interaction (like SMS) and it is voice over IP (VOIP) so it does not use minutes on a cellular plan.

Applications on the market that offer this walkie-talkie style interaction for audio include Voxer, Zello, Orion Labs, Motorola Wave, and HeyTell, among others.

Other smartphone-based walkie-talkie products are made by companies like goTenna, Fantom Dynamics and BearTooth, and offer a radio interface. Unlike mobile data dependent applications, these products work by pairing to an app on the user’s smartphone and working over a radio interface. These products are consumer oriented implementations of technologies that have been widely available to HAM radio enthusiasts for years.

1.6                                                 SCOPE OF THE PROJECT

A walkie-talkie is a half-duplex communication device; multiple walkie-talkies use a single radio channel, and only one radio on the channel can transmit at a time, although any number can listen. The circuit can only be “half-duplex” speaking, that is, between the host and only one said extension, the other to listen to, but not both at the same time I heard. Listening, speaking from the conversion switch S1, S1 is located in the host Department. S1 position can be shown that the extension, the host to listen to; if S1 allocated to the bottom to become the host says.

1.7                                         SIGNIFICANCE OF THE PROJECT

Walkie talkies, or two-way radios, are no longer only meant for military and police use. Their usefulness and versatility has made them indispensable in a number of business environments, with units available that are handheld or built into vehicles. Although walkie talkies have a limited range, they are free to use and, as a result, cheaper to run than cell phones. Once handsets have been bought and paid for there are no monthly call charges. They are simple and easy to use, with most models featuring a push-to-talk button that allows the user to send messages, and a speaker to relay messages back to the user.

In general, a wide variety of businesses benefit from the use of walkie talkies. They are often used to enhance businesses’ health and safety practices, as public address (PA) systems, and to keep employees informed of urgent information throughout the course of the day.

1.8                                 PROBLEM/LIMITATION OF THE PROJECT

1. Losing Coverage: Losing coverage refers to instances where you are mid-transmission with someone and all of a sudden the conversation is cut short, or you find that you can only hear the other person very faintly as if they are whispering.  This is down to the problem of poor coverage.
2. Interference with radios: You are hearing additional noises on the two-way radios or other conversations.  As much this could be interesting to overhear conversations, bear in mind, if you can here others they could hear you – it takes two to tango!  This becomes a nuisance if you are trying to transmit an emergency or an important message.
3. Discrete communication: Walkie talkieshaven’t got the reputation for being the most discrete communication devices.  Normally when someone transmits a message everyone can hear it.  This is an issue if someone wants to transmit a message that needs to be only heard by the person receiving the message and no one else.  For instance any security issues that need to be within the security staff and not shoppers on the shop floor.
4. Cannot hear the voice as there is too much background noise: Places such as constructions, railway and stadiums, there will be too much noise to hear clear, even hear nothing.
5. Battery Problem: the device will stop working when the battery runs down.

1.8                          PROJECT WORK ORGANISATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

Chapter one of this work is on the introduction to a walkie talkie. In this chapter, the background, significance, objective limitation and problem of walkie talkie were discussed.

Chapter two is on literature review of walkie talkie. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.

Chapter five is on conclusion, recommendation and references.