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SUMMER TRAINING REPORT

ON

EMBEDDED SYSTEM

AT

ATECH LABS

BHARATI VIDHYAPEETH’S COLLEGE OF ENGINEERING

A-4, PASCHIM VIHAR, ROHTAK ROAD, NEW DELHI- 110063

AFFILIATED TO

GURU GOBIND SINGH INDRAPRASTHA UNIVERSITY, DELHI

(2009-2012)

SITE OF TRAINING: SUBMITTED BY: S.C.O. :160 ,SEC :24-D NITISH

CHANDIGARH ELECTRONICS & COMMUNICATION ENGG.

ROLL NO – 00111507309

UNDER GUIDANCE OF:MR. LAKHBIR SINGH



1.3 Life cycle of a microcontroller project Before going further, is important to have a general idea of the steps that are

followed to realize a project, from the very beginning when you get an idea to

the very end when you finalize your project.

As you can see in figure

1.5.A, after you settle on

the choice of your

project in the 'brain

storming' part, its

imperative to imagine

how it can be

implemented from the

hardware point of view,

before passing to the

programming phase,

because programming is

much more flexible than

the hardware design. In

other words, you start by

designing the hardware,

then you work on the

programming while

taking in consideration

the eventual constraints

imposed by the hardware

design.

Figure 1.5.A

The hardware design includes all the aspects of the electronic connections

between other devices, like the compatibility of the voltage levels, or the

required number of pins, etc...

After you're done with a first version of your program, you can transfer it to the

microcontroller mounted on the board that you realized already, resulting in a

first prototype. The transfer of the code is done using a special device called

'burner' or 'programmer' that connect to the computer, reads the HEX file

generated by the compiler, and sends it to the 'program memory' of the



2.1 Definition of a Microcontroller

Microcontroller, as the name suggests, are small controllers. They are like

single chip computers that are often embedded into other systems to function as

processing/controlling unit. For example, the remote control you are using

probably has microcontrollers inside that do decoding and other controlling

functions. They are also used in automobiles, washing machines, microwave

ovens, toys ... etc, where automation is needed.

Figure 2.1: Showing a typical microcontroller device and its different subunits



4.1 INTERFACING OF LED WITH

MICROCONTROLLER

LED Displays

LED displays are packages of many LEDs arranged in a pattern, the most

familiar pattern being the 7-segment displays for showing numbers (digits 0-9).

The pictures below illustrate some of the popular designs:

Pin connections of LED displays

There are many types of LED display and a

supplier's catalogue should be consulted for

the pin connections. The diagram on the right

shows an example from the catalogue. Like

many 7-segment displays, this example is

available in two versions: Common Anode

(SA) with all the LED anodes connected

together and Common Cathode (SC) with all the cathodes connected together.

Letters a-g refer to the 7 segments, A/C is the common anode or cathode as

appropriate (on 2 pins). Note that some pins are not present (NP) but their

position is still numbered

Fig. 4.3 Pin connections diagram



6.1 PROJECT OVERVIEW

In this project the system, is controlled by a mobile phone that makes

call to the mobile phone attached to the system in the course of the call, if any

button is pressed control corresponding to the button pressed is heard at the

other end of the call. This tone is called dual tone multi frequency tone (DTMF)

microcontroller receives this DTMF tone with the help of phone stacked in the

decoder.

The received tone is processed by the microcontroller with the help of DTMF

decoder CM8870 the decoder decodes the DTMF tone in to its equivalent

binary digit and this binary number is send to the microcontroller, the

microcontroller is programmed to take a decision for any give input and outputs



9.1 INTRODUCTION:

A relay is an electrically operated switch. Many relays use an electromagnet to

operate a switching mechanism mechanically, but other operating principles are

also used. Relays are used where it is necessary to control a circuit by a low-

power signal (with complete electrical isolation between control and controlled

circuits), or where several circuits must be controlled by one signal. The first

relays were used in long distance telegraph circuits, repeating the signal coming

in from one circuit and re-transmitting it to another. Relays were used

extensively in telephone exchanges and early computers to perform logicaloperations.



called from anywhere in the world and by pressing the keys the DTMF tones

can be transmitted to the receiving end mobile and hence any device

connected can be operated globally.

Figure 6.1 Block diagram of the system using DTMF.

In order to operate the system you have to make a call to the cell phone

attached to the main circuitry of the project from any other phone. The phone is

picked at the receiving end through auto answer mode (which is in the phone,

just enable it). Each number on the cell phone keypad has a distinct sound

(called DTMF tones). This sound is used to identify the key pressed, using a

CM8870 DTMF decoder. Here the sound is firstly preamplified by the

microphone unit. This sound is now fed into the M8870 IC which decodes them

in form of numbers. These decoded numbers are fed into the microcontroller .It

checks the code and energize/de-energize that particular relay for which that

signal is send ,in response of which the switching takes place in the appliance

which is connected to it. Like:

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