Project synopsis

OnAutodialler Security system with voice

message

Submiited to:

Submitted by:

OBJECTIVE

Auto Dialler Circuit

IntroductionIn this project we show that how we use the telephone as a electronics eye.

With the help of landline phone we check and examine the position of the

house automatically. In this logic we attach some sensor with the telephone

and if there is any mis happening then telephone is automatic on and then

circuit press the redial button of the telephone and then telephone dial the

pre-dialied number and sense the voice message to the received end. All

these logic is to be divided into few parts.

ACTION OF STEPS

Sensor unit.

Micro controller interface

Switch on the telephone

Redial the number

Activate the voice processor.

Transfer the message on the telephone line

Switch off the telephone line after sending the message.

SENSOR UNIT.

In this sensor unit it is our choice , how many sensor’s we use , IN this

project we use two sensor’s, In this project we use two electronics circuit

with infra red sensor’s and fire alarm sensor.

In the infra red sensor. We use ic 555 as a main component. Pin no 4 and pin

no 8 is connected to the positive supply. Pin no 1 is connected to the

negative voltage. One capacitor is grounded from the pin no 5 for noise

cancellation. Output is available on the pin no 3. Sensor is connected to the

pin no 2.

In the case of infra red sensor. Pin no 2 is negative bias through the 33k ohm

resistor and pin no is positively biased through the photodiode. One infra red

transmitter l.e.d is focused to the photodiode . Infra red l.e.d is directly

connected to the positive and negative supply through the 470 ohm resistor..

In normal stage when light is focus on the photodiode then pin no 2 is

positively biased photodiode. If pin no 2 is positive then negative output is

available on the pin no 3. Now when any body interrupt the light then there

is no light on the photodiode and pin no 2 is now gets its voltage from only

33 k ohm resistor. If pin no 2 is become negative then output is shifted to

the pin no 3. when positive output is available on the pin no 3 and with the

help of this voltage NPN transistor is on and npn transistor provide a

negative voltage as a pulse to the microcontroller.

If we connect two sensor as a input to the microcontroller then we use same

circuit with the ic 555 .

Note that microcontroller sense only negative input to the microcontroller.

MICROCONTROLLER CONTROL.

ATMEL AT89C2051 Pinout and Description

The 2051 is a low voltage (2.7V - 6V), high performance CMOS 8-bit microcontroller with 2 Kbytes of Flash programmable and erasable read only memory (PEROM). This device is compatible with the industry standard 8051 instruction set and pinout. The 2051 is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control applications. The 2051 provides the following features:

~ 2 Kbytes of Flash ~ 128 bytes of RAM ~ 15 I/O lines ~ two16-bit timer/counters ~ five vector, two-level interrupt architecture ~ full duplex serial port ~ precision analog comparator ~ on chip oscillator and clock circuitry

In addition, the 2051 is designed with static logic for operation down

to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The Power Down Mode saves the RAM contents but freezes the oscillator disabling all other chip functions until the next hardware reset.

To learn how to use the 2051 microcontroller, get the Microcontroller Beginner Kit (click here)

2051 - 24MHz DIP Available

The 2051 can be programmed using a device programmer such as the PG302 (Click Here).

We also have Projects that use the 2051 Microcontroller. See the Intermediate Tutorial Section.

This page last updated on April 7, 2003.

All the input sensor is connected to the pin no 18 and 19. Pin no 18 is

connected to the P1.6, and pin no 19 is connected to the P1.7. pin no 20 is

connected to the positive supply. Pin no 1 reset pin. One capacitor is

connected from positive to pin no 1 and one resistor is grounded from pin

no 1. One microswitch is connected across the capacitor fro manual reset

switch.

One buzzer is connected to the pin no 16 ( Port p1.4) this buzzer is on when

circuit sense a input from the input sensor’s. .

Microcontroller sense the input and then we switch on the telephone line

optocoupler. Here we use 817 optocoupler. Once the optocoupler is on one

270 resistor is connected in parallel with the telephone line. After this we

press the flash button of the telephone dialer circuit. For flash purpose we

provide a negative pulse to the flash point for this we CLR P1.1 and after

some delay we SET the P1.1 and after pressing the flash button we press the

redial number. For this we press the pin no 12 ( port p1.0) and after some

delay again we set the P1.0

After pressing the flash button, redial button and switch on the telephone

line we switch on the memory ic. We press the pin no 24 of the isd 1420.

ISD 1420 is a voice processor ic. Output from the voice processor is

available on the pin no 14 and 15 and this output is coupled to the

transformer and output from this transformer is connected to the telephone

line. At the same time telephone dialer ic provide a pulse of the telephone

number to the telephone line.

Telephone dialer circuit.

In this portion of telephone dialer circuit we use the telephone dialer

circuit. For this we use one dtmf generator circuit to generate a dtmf tones

from the circuit. For this purpose we use one DTMF generator circuit to

generate a dtmf tones from the circuit. We connect one telephone keypad or

push to on switches with this circuit. We use total 14 push to on switches

with this circuit to dial the dtmf tones. Once we dial the number in the

dialer circuit. Now when micrcontroller press the redial switch then circuit is

on and redial the pre-dial number .

All the switches are connected to the pin no no 12,13,14,15,16,17,18. All the

switches are connected in row and matrix combination including redial and

flash switch

DTMF LOGIC

In DTMF there are 16 distinct tones. Each tone is the sum of two frequencies: one from a low and one from a high frequency group. There are four different frequencies in each group.

Your phone only uses 12 of the possible 16 tones. If you look at your phone, there are only 4 rows (R1, R2, R3 and R4) and 3 columns (C1, C2 and C3). The rows and columns select frequencies from the low and high frequency group respectively. The exact value of the frequencies are listed in Table 3 below:

TABLE 3: DTMF Row/Column Frequencies

LOW-FREQUENCIES

ROW # FREQUENCY (HZ)

R1: ROW 0 697

R2: ROW 1 770

R3: ROW 2 852

R4: ROW 3 941

HIGH-FREQUENCIES

COL # FREQUENCY (HZ)

C1: COL 0 1209

C2: COL 1 1336

C3: COL 2 1477

C4: COL 3 1633

C4 not used in phones

Thus to decipher what tone frequency is associated with a particular key, look at your phone again. Each key is specified by its row and column locations. For example the "2" key is row 0 (R1) and column 1 (C2). Thus using the above table, "2" has a frequency of 770 + 1336 = 2106 Hz The "9" is row 2 (R3) and column 2 (C3) and has a frequency of 852 + 1477 = 2329 Hz.

The following graph is a captured screen from an oscilloscope. It is a plot of the tone frequency for the "1" key:

You can see that the DTMF generated signal is very distinct and clear. The horizontal axis is in samples. The frequency of the tone is about 1900 Hz - close to the 1906 Hz predicted by Table 3 (697+1209).

CIRCUIT DIAGRAM USE IN THIS PROJECT FOR TELEPHONE

DIALLER IS GIVEN BELOW. In this circuit we use ic 91215 as adtmf

generator. Pin no 15,16,17,18 is a row and pin no 12,13,14 is a row. All the

switches are connected to these pins. Redial button and flash button is

connected to the microcontroller output pin s no 13 and 12 . Output from the

91215 is available on the pin no 7 of the ic . Output from the 91215 is

further amplify by the ic 741. Here pin no 7 of the ic 741 is connected to the

positive supply and pin no 4 is connected to the negative supply. Pin no 6 is

the output pin and amplify signal is available on this pin and again further

amplify by the two transistor circuit. Output from the transistor circuit is

connected to the one coil of the output transformer.

Now when we press a redial number then 91215 generate a pre-dial tones

and this signal is further connected to the coil and further pass on the

telephone line.

Components required:

IC4433

Ic 91214

89c2051

push to on sw

555 timer

.001 µf,0.1 µf,0.01µf

1µf,

220k,470k,4.7k,10k,

crystal 11.0592 MHz

3.38 MHz.

buzzer,

condenser Mic

speaker 8 ohm

relay 12v 100 ohm

transformaer 6v 500mA

infrared Sensor,

heat Sensors

connecting wires

copper clad board

tel line

mic

speaker

BLOCK DIAGRAM AUTO DIALER

SECURITY SYSTEM

STEPS TIME RESPONSIBILTY

PROJECTS

MCU

Speech ICFor voice recording

Auto Dialler Circuit

DTMFencoder

Keyboard

Timer Circuit

Sensor input

SELECTION

CIRCUIT AND

THEORY

ARRANGEMENT

CHECKING

AVAILABILITY

OF

COMPONENTS

TESTING

CIRCUIT

PCB DESIGN

COMPONENT

INSERTION AND

SOLDERING

TESTING

REWORK OR

TROOUBLE

SHOOTING

Uses:Easy to implementReliable,Low cost,Components easily available in market.

Applications:

Home security

Car security

In hospital patient security

Machine monitoring

Bibliography:

www.ludhianaprojects.com/auto dialler.doc