Design And Construction Of An Infrared (IR) Transmitter And Receiver

This work is design and construction of an Infrared (IR) based transmitter and receiver, which is a wireless communication technology. Infrared (IR) communication is used in remote controls of different appliances like TV’s. The handheld remote control of the TV consists of IR Transmitter and the IR Receiver is placed at the TV. An infrared transmitter and receiver consist of IR Transmitter and Receiver Modules. In this project, we build a simple IR Transmitter and Receiver using 555 Timer.

The aim of the project is to explain how Infrared (IR) communication works with the help of simple hardware. For this project, we have used TSOP 1738 IR Receiver to receive infrared signals and a simple IR LED to transmit infrared signals. The circuit diagram, components and the working is explained in the work.

CHAPTER ONE

1.0                                         BACKGROUND OF THE PROJECT

The era of wire or cable connection for reception of audio and video media is almost obsolete. Now technology is making everything wireless and stress free. This device is another brilliant technology that can let you connect your audio and video footage from one point to another without wires, example connect different TVs in different locations(rooms) from your DVR(DSTV Decoder) without running wires, CCTV cameras to Monitor without running wires, DVD to TVs or speakers in different rooms without running cables.

IR Transmitter and receiver are used to control any device wirelessly, means remotely. TV remote and TV are the best example of IR transmitter and receiver. TV generally consist TSOP1738 as the IR receiver, which senses modulated IR pulses and convert them into electrical signal. In this work we are building IR remote and its receiver.  It was built around IR LED as transmitter and TSOP1738 as IR receiver.

IR LED emits infrared light, means it emits light in the range of Infrared frequency. We cannot see Infrared light through our eyes, they are invisible to human eyes. The wavelength of Infrared (700nm – 1mm) is just beyond the normal visible light. Everything which produce heat, emits infrared like our human body. Infrared have the same properties as visible light, like it can be focused, reflected and polarised like visible light.

1.1                                                   AIM OF THE PROJECT

The aim of the project is to explain how Infrared (IR) communication works with the help of simple hardware. For this project, we have used TSOP 1738 IR Receiver to receive infrared signals and a simple IR LED to transmit infrared signals.

1.2                                             OBJECTIVE OF THE PROJECT

The objective of this work is to design and implement a device for transmitting domestic audio and video signals wirelessly from one location to another. The frequency at which it is transmitted has much more available bandwidth than that which is available at the analogue level.

1.2                                              PURPOSE OF THE PROJECT

The purpose of this work is to transmit audio/video signals of cable, satellite, video camera, DVD player, VCR, projector, or computer, etc. from one room to another wirelessly using infrared communication.

• SIGNIFICANCE OF THE PROJECT

1. This device is important because it can transfer information – audio, video, our voices, data — without the use of wires, and that makes them very useful.
2. IR Transmitter and Receiver pair form a simple circuit which can be easily built.

• Can be used for simple remote controlling applications, small data transfer, etc.

1. IR Transmitter and Receiver pair as a module can be used in security applications, proximity sensors, distance measurement applications, etc.

1.4                                                 SCOPE OF THE PROJECT

This device transfers data or information – audio, video, our voices, and data — without the use of wires. These systems involve two components, one of which contains an IR receiver and an IR transmitter. The paired unit contains  an ir receiver and IR transmitter. When an infrared remote is used on the IR receiver, the device translates the signal and broadcasts it over  infrared mode.

TSOP 1738 is an IR Receiver for IR (Infrared) remote controls. It consists of Photo Detector, Gain Control, Band Pass Filter, Demodulator and a Pre – amplifier in a single package. IR LED which is the transmitter is a special type of LED that emits Infrared rays of the Electromagnetic Spectrum. The wavelength of Infrared Rays is greater than that of Visible light and hence they are invisible to human eye.

For the modulating circuit, we use 555 Timer IC in Astable Multivibrator mode. In this mode, the 555 IC will work as a free running oscillator and generates an approximate 38 KHz square wave. The output of the 555 IC is connected to an IR LED through a button.

1.5                                          APPLICATION OF THE PROJECT

This device is used to connect home entertainment and AV devices in a home or a business. These transmitters are also used to connect security cameras to displays and recorders. For instance, a home security system can be set up that utilizes a video transmitter for cameras that monitor the front door, or a home theatre can be set up with transmitters to allow video signals to be beamed to different TVs in the home. IR transmitters are used to send a video signal from any AV or HD video source to a receiver in another location.

1.6                                              PROBLEM OF THE PROJECT

Obstructions: An obstruction refers to anything that is between the transmitter and receiver and is obstructing the signal from reaching the receiver successfully. Although wireless videos can transmit through walls, there is always some degradation of the signal. If obstructions like walls or thick trees are unavoidable, the solution is to get the transmitting and receiving antennas up as high as possible, as many of the obstructions that the signal encounters include furniture and other items sitting on the floors.

Interference: interference and false triggering might likely occur. In order to prevent interference and false triggering, if the infrared light is not properly modulated. The modulated signal can only be demodulated by the appropriate IR Receiver.

1.7                                           LIMITATION OF THE PROJECT

1. IR Transmitter and Receiver require line of sight communication i.e. they need to be facing each other.
2. The range of IR communication is less and is reliable for short range and small amounts of data

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 this study. In this chapter, the background, aim, purpose, significance, scope, objective, limitation and problem was discussed.

Chapter two is on literature review of the study. 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.