device control using gsm mobile phone project electronics

GLOBUS ENGINEERING COLLEGE, BHOPAL

Department of Electronics & Communication. Year -2011

Table of Content

1. Project Introduction ---------------------------------------------1

2. Literature Review ------------------------------------------ --2

3. Project Plan

3.1 Problem Statement ------------------------------------------ --4

3.2 Operating Environment ------------------------------------------ --4

3.3 Intended Users & Uses ------------------------------------------ --5

3.4 Assumptions ------------------------------------------ --5

4. Proposed Approach

4.1 Functional Requirements ------------------------------------------ --6

4.2 Constraint Considerations ------------------------------------------ --6

4.3 Technology Considerations ------------------------------------------ --7

4.4 Technical Approach ------------------------------------------ --7

5. Testing Requirements

5.1 GSM Receiver ------------------------------------------ --8

5.2 GSM to Microcontroller ------------------------------------------ --8

5.3 Decoding of Remote User’s commands ------------------------------------------- -9

5.4 I/O Command’s Voltage ------------------------------------------ --9

5.5 I/O Command Storage ------------------------------------------ --9

5.6 Circuit’s Power Surge Protection ------------------------------------------ --10

5.7 End Product Functionalities ------------------------------------------ --10

6. System Block diagram ------------------------------------------ --11

7. Circuit Diagram

7.1 Circuit Diagram ------------------------------------------ --12

7.2 Power Supply Section ------------------------------------------ --13

7.3 Relays ------------------------------------------ --14

8. PCB Layout ------------------------------------------ --15

9. Microcontroller Programming ------------------------------------------ --16

10. Component List ------------------------------------------ --17



11. Component Description

11.1 Resistors -------------------------------------------18

11.2 Capacitors -------------------------------------------19

11.3 LED -------------------------------------------19

11.4 Transistors -------------------------------------------20

11.5 Transformer -------------------------------------------21

11.6 Diodes -------------------------------------------22

11.7 Relay -------------------------------------------22

11.8 Microcontroller ATtiny2313

11.8.1 Features -------------------------------------------23

11.8.2 Pin Out -------------------------------------------24

11.8.3 Block Diagram -------------------------------------------25

11.9 DTMF Decoder MT8870

11.9.1 Description & Features -------------------------------------------26

11.9.2 Pin Out Description -------------------------------------------27

11.10 ULN 2003 IC -------------------------------------------28

11.11 Voltage Regulator IC MC7812 & LM7805 -------------------------------------------29

11.12 Diode IN4007 -------------------------------------------30

12. PCB Manufacturing Process -------------------------------------------31

13. Design Specification

13.1 PCB Designing -------------------------------------------33

13.2 LAYOUT Design -------------------------------------------34

13.3 Etching Process -------------------------------------------35

13.4 Component Assembly -------------------------------------------36

13.5 Soldering -------------------------------------------38

14. Working -------------------------------------------39

15. Application -------------------------------------------40

16. Chronology --------------------------------------------41

17. Bibliography --------------------------------------------42


Page 1


1. PROJECT INTRODUCTION

Our project Device Control Using GSM Mobile Phone is a setup or system

in which we can easily ON/OFF the appliances using in home. The

appliances are connected through a circuit which is connected to a GSM

mobile phone via a DTMF Tone Decoder IC.

It often happens that we forget to switch off some electric devices

while leaving home for a journey. This will result in wastage of energy and

even the device may get damaged due to overheating. Even if we remember

that we have not switched off some devices, it may be difficult for us to come

back and switch them off. Also, if we are away from home we may have to

turn on the lights at night. These are normally not possible in present

condition.

Our project offers a novel solution for this problem by using a

GSM mobile phone, a common electronic gadget. This device is build around

PSoC, a powerful system-on-chip. This uses DTMF (Dual Tone Multi

Frequency) signals from mobile phone keypad to attain its functionality. For

decoding the DTMF tones, we are using MT8870, CMOS Integrated DTMF

Receiver.

FEATURES

The main features of our device control system are:-

Easy control of devices through mobile phone

Can control (on/off) a maximum of 8 devices (by using decoder we can

increase this number to 256)


Page 2


2. Literature Review

Smart home is one of the recent fields in the context of computer

science. The paper named as “Remote mobile control of home appliances”

by F. Meija, M. Nikolova and P. Voorwinden depicts on the home

controlling using WAP protocol. The architecture mentioned by them is

much complex but it gives an initial idea about the remote home appliance

controlling.

Smart home studies sometimes affected by the concern about the

possible harms to the humans’ health. A great research was done by Toril

Laberg, Directorate for Health and Social Affairs of the Delta Centre,

Norway. He later publish in his paper named “Smart Home Technology:

Technology supporting independent living - does it have an impact on

health?” that there is no harm on humans’ health by the technical setup

required to support smart home technologies.

Scott Davidoff, Min Kyung Lee, Charles Yiu, John Zimmerman,

and Anind K. Dey in their journal named “Principles of Smart Home

Control” describe the control that families want and suggest seven design

principles that will help end-user programming systems deliver that

control.

Tatsuya Yamazaki in his journal “The Ubiquitous Home”

suggests that automation should not become a goal of the smart home

technologies. In this paper he represents a real-life test bed, called the

Ubiquitous Home. In the Ubiquitous Home, a robot plays a role of

interface for the residents. Three kinds of context-aware services have

been implemented and a real-life living experiment was conducted. The

experimental results were also reported.


Page 3


Recently some projects are organized for building the architecture of

controlling home appliance using voice commands. VoiceXML is used for

that purpose.

A smart house system named NETVOX [18] based on the ZigBee

standard is introduced recently. The system can use for home automation

and industrial controls. It provides security, temperature, humidity,

lighting, sensor, and multimedia control for comfort, convenience, and

safety wirelessly. The system may be accessed and controlled over the

telephone or over the Internet.


Page 4


3. Project Plan

This section will state the basic problem, and the basic characteristics of

the project, such as operating environment, users, etc.

3.1 Problem Statement

The objective of this project is to develop a device that allows for a user

to remotely control multiple home appliances using a cellular phone. This

system will be a powerful and flexible tool that will offer this service at any

time, and from anywhere with the constraints of the technologies being

applied. Possible target appliances include (but are not limited to) climate

control systems, security systems, and lights; anything with an electrical

interface.

The proposed approach for designing this system is to implement a

microcontroller-based control module that receives its instructions and

commands from a cellular phone over the GSM network. The microcontroller

then will carry out the issued commands.

3.2 Operating Environment

The control system will include two separate units: the cellular phone, and

the receiving control unit. There will therefore be two operating

environments. The cellular phone will operate indoors and outdoors whereas

the receiving control unit will operate indoors within the temperature and

humidity limits for proper operation of the hardware.


Page 5


3.3 Intended Users and Uses

This product is aimed toward average consumers who wish to control

household appliances remotely from their cell phones provided that the

appliances are electrically controllable. Example of feasible appliances and

applications under consideration include; enable/disable security systems,

fans, lights, kitchen appliances, and a heating/ventilation/air conditioning

system.

3.4 Assumptions

The following is a list of assumptions for the project:-

1. The user and receiver control unit will establish communication via

GSM.

2. The cell phone and service provider chosen will support calling service.

3. The user is familiar with the call process & IVRS on cell phone.

4. All service charges from service provider apply.

5. The controlled appliances will have to have an electrical interface in

order to be controlled by microcontroller.


Page 6


4. Proposed approach

This section outlines the criteria that will be considered in the

development of the control system.

4.1 Functional Requirements

The following is a list of functional requirements of the control

unit/module.

The Cellular Unit will have the ability to connect to the cellular

network automatically.

The Cellular Unit will be able to receive call and will be able to send

DTMF tone to the DTMF Decoder IC.

The DTMF Decoder IC will decode the (pressed no. by user’s cell

phone & received on Cellular Unit) DTMF tone into the 4bit BCD

output signal.

The microcontroller connected to the DTMF decoder IC will receive

the BCD output.

The logic programmed in microcontroller drive the signal to the O/P

ports of microcontroller as per the BCD O/P.

Microcontroller will issue its command to the electrical appliances

through a simple control circuit.

4.2 Constraint Considerations

The following is a list of constraint considerations:-

The controlled appliances will need an electrical control interface.

This simple system is only capable of controlling electrical devices.

The control module will need to be shielded against electrostatic

discharges. This will increase reliability of the system.


Page 7


4.3 Technology Considerations

The considerations for this system will include a choice of networks,

communication protocols, and interfaces.

1) Cellular Networks: The widely available networks are based on

GSM. This network provides a wide area of coverage and can be

utilized more cost-effectively for this project.

2) Communication protocols: The available communication protocols

are DTMF, GPRS and SMS. The DTMF is the most efficient

because this project requires a cellular communication and only by

pressing keys we can control appliances.

3) I/O interfaces between microcontroller and devices: Serial or

parallel I/O will be considered as options for connection between the

GSM receiver and the microcontroller. Using the microcontroller, a

control circuit will be implemented to control the electrical

appliances.

4.4 Technical Approach

Assuming that the control unit is powered and operating properly, the

process of controlling a home device will proceed through the following

steps:-

The remote user makes a call to the GSM cellular unit and

commands to the receiver.

GSM receiver receives call automatically from user cell phone by

auto answering mode.

After receiving call by GSM cellular unit user press the keys on

his cell phone.

GSM receiver receives the appropriate DTMF tone.

The DTMF decoder IC connected to GSM receiver detects the

pressed DTMF tone & converts it to the 4 bit BCD O/P.

DTMF decoder IC sends the BCD O/P to the microcontroller.

Microcontroller issues commands to the appliances via relays

connected to its O/P ports.


Page 8


5. Testing Requirements The following testing requirements will be indicators that the system can

successfully be implemented.

1) The GSM receiver will be tested for successful communication with

network. This will test include automation and consistency of the

connection and will be conducted by team members in the following way:

The cellular phone will dial the GSM receivers’ number.

Once the connection is established a stream of data will be

send to the GSM receiver.

The GSM receiver will be given data to be transmitted to the

cellular phone.

Success/Failure criteria: The data received will be observed on both ends to

verify its consistency. The test will be considered successful if the integrity of

the sent and received data is maintained upstream. It will be considered a

failure otherwise.

2) The GSM to microcontroller driver will be tested by verifying the

integrity of command strings sent from the remote user. The following

procedure will be performed by team members for this phase:

The remote user will send a command to the control module.

The contents of the data stream will be observed at the GSM

communication port.

These contents will be compared with those received and

stored at the microcontroller’s corresponding communication

port.

Success/Failure criteria: The test will be considered successful if the

integrity of the data sent upstream is maintained. It will be

considered a failure otherwise.


Page 9


3) Proper decoding of the remote user’s commands and issuance of the

equivalent commands to the controlled device will be performed by team

members using the following procedure:

A simulated instruction will be fed to the microcontroller

communication port.

The output command at the I/O interface with the

corresponding controlled device will be observed.

Success/Failure criteria: The test will be considered a success if the resulting

command issued from the microcontroller is sent to the right I/O address for

the desired controlled device and if that command is consistent with the

command which is expected. The test will be considered a failure otherwise.

4) The I/O command’s voltage will be tested to meet the levels required to

actuate the individual devices. The following procedure will be

performed by team members:

A simulated command from the microcontroller will be

written to its I/O port.

The output voltage at the desired device’s control interface

will be measured to verify its strength.

Success/Failure criteria: The test will be considered successful if the

simulated command from the microcontroller causes the proper voltage to be

observed at the desired device’s control interface.

5) The ability of I/O to detect an input voltage and store a value in the

microcontroller’s memory will be tested by team members:

Test voltages to the input of the I/O will be applied.

The contents of the memory shall be checked for validity.

Success/Failure criteria: The testing will be considered successful if the

values of the memory are as expected. The test will be considered a failure

otherwise.


Page 10


6) The circuit’s power surge protection will be tested for acceptable

performance by EE team members using the following procedure:

The circuit’s power supply will be removed from the circuit

and connected to a dummy load.

A simulated voltage spike will be inputted by using a step

signal from a signal generator.

The output voltage and current will be measured at the load.

Success/Failure criteria: The success of the test will be determined by

verifying that the output signal to the dummy load falls with the tolerance

indicated by the microcontroller and the GSM chip’s manufacturers. The test

will be considered a failure if the measured characteristics of the power

supply’s output do not meet the manufacturers’ requirements.

7) The end-product functionalities will be tested by team members and

non-team members in the following way:

Team members will ensure that all subsystems function

properly together from remote user command to execution and

back to completion status notification.

Non-team members from the general public will be allowed to

access and use the control unit for a frame of time.

Afterward, the non-team member testing subjects will fill out

a survey on the end-product’s functionalities, ease of use,

difficulties, etc.

Success/Failure criteria: The testing will be considered a success if the

testing subjects find the end-product user friendly, and easy to figure out.


Page 11


6. System Block Diagram

The block diagram of the system is given below:

ATtiny2313

Microcontroller

Receiving

Cell Phone

Unit

DTMF

Decoder

MT8870

RELAY1

RELAY2

RELAY3

RELAY4

RELAY5

RELAY6

RELAY7

DEVICE1

DEVICE 2

DEVICE3

DEVICE4

DEVICE5

DEVICE6

DEVICE7


Page 12


7. CIRCUIT DIAGRAM


Page 13


POWER SUPPLY SECTION


Page 14


RELAYS


Page 15


8. PCB LAYOUT


Page 16


9. Microcontroller Programming

ATtiny2313 is programmed by the BASECOM-AVR IDE [1.11.9.5]. We have

used this Integrated Development Environment Software for program the 4 bit

input coming into microcontroller to drive the appropriate relays.

LOGIC

The basic logic used that configure the IC MT8870 through making the port D as

input. The 4 bit BCD input taken from PinD0, PinD1, PinD3, PinD4. The O/P port

is PORTB to drive the relays are port pins PORTB 1 – PORTB 7.

As depending on input signals we used the IF ELSE conditions to drive the relays

1-7, when signal input is 1. Whereas there is no signal input means no BCD input

to microcontroller.


Page 17


10. COMPONENT LIST

Component Name Quantity Price(Amount)

GSM Mobile Phone 1 `1000 Transformer [0-15V, 750mA] 1 `190 Microcontroller IC ATtiny2313 1 `150 DTMF Decoder IC 1 `38 Driver IC ULN2003 1 `35 Regulating IC MC7812 1 `20 Regulating IC LM7805 1 `18 Relays [SPDT, 12V] 7 `126 Diode IN4007 4 `8 Capacitor [1000µF, 25V] 1 `25 Capacitor [100µF, 25V] 1 `20 Capacitor [10µF, 25V] 1 `15 Capacitor [0.1µF, 50V] 6 `30 Capacitor [22pF] 2 `4 Crystal Oscillator 11.0592 MHz 1 `15 Crystal Oscillator 3.57MHz 1 `15 Red LED 8 `16 Green LED 1 `2 Resistance 1kΩ 9 `4.50 Resistance 560Ω 1 `0.50 Resistance 330kΩ 1 `0.50 Resistance 100kΩ 2 `1 Wire main cord 1 `25 Connecting Wires bundle 1 `30 Solder Wire 50 gram `75 CCB -18 [6x6] 1 `40 FeCl3 50 gram `35 Soldering Iron 1 `100 Hand Drill 1 `120 0.8 mm bit 5 `30 1mm bit 1 `35 Total `2223.50


Page 18


11. COMPONENT DESCRIPTION

11.1 RESISTORS: -

A Resistor is a heat-dissipating element and in the electronic circuits it

is mostly used for either controlling the current in the circuit or developing a

voltage drop across it, which could be utilized for many applications. There

are various types of resistors, which can be classified according to a number

of factors depending upon:

(I) Material used for fabrication

(II) Wattage and physical size

(III) Intended application

(IV) Ambient temperature rating

(V) Cost

Basically the resistor can be split in to the following four parts from the

construction viewpoint.

(1) Base

(2) Resistance element

(3) Terminals

(4) Protective means.

Resistors may be classified as

(1) Fixed

(2) Semi variable

(3) Variable resistor.

(4) In our project carbon resistors are being used.


Page 19


11.2 CAPACITORS

The fundamental relation for the capacitance between two flat plates

separated by a dielectric material is given by:-

C=0.08854KA/D

Where: -

C= capacitance in pf.

K= dielectric constant

A=Area per plate in square cm.

D=Distance between two plates in cm

Design of capacitor depends on the proper dielectric material with

particular type of application. The dielectric material used for capacitors may

be grouped in various classes like Mica, Glass, air, ceramic, paper,

Aluminum, electrolyte etc. The value of capacitance never remains constant.

It changes with temperature, frequency and aging.

11.3 LED (Light Emitting Diodes)

As its name implies it is a diode, which emits light when forward biased. Charge

carrier recombination takes place when electrons from the N-side cross the

junction and recombine with the holes on the P side. Electrons are in the higher

conduction band on the N side whereas holes are in the lower valence band on the

P side. During recombination, some of the energy is given up in the form of heat

and light. In the case of semiconductor materials like Gallium arsenide (GaAs),

Gallium phoshide (Gap) and Gallium arsenide phoshide (GaAsP) a greater

percentage of energy is released during recombination and is given out in the form

of light. LED emits no light when junction is reverse biased.


Page 20


11.4 TRANSISTOR: -

A transistor consists of two junctions formed by sandwiching either p-

type or n-type semiconductor between a pair of opposite types. Accordingly,

there are two types of transistors namely: -

(1) n-p-n transistor (2) p-n-p transistor

(NPN) (PNP)

An n-p-n transistor is composed of two n-type semiconductors separated by a

thin section of p type. However a p-n-p transistor is formed by two p sections

separated by a thin section of n-type. In each type of transistor the following

points may be noted.

1. There are two p-n junctions; therefore a transistor may be regarded as

combination of two diodes connected back to back.

2. There are three terminals taken from each type of semiconductor.

3. The middle section is a very thin layer, which is the most important

factor in the functioning of a transistor.

Transistor can be used as an Amplifier also.

A transistor raises the strength of a weak signal and thus acts as an

amplifier. The weak signal is applied between emitter base junction and

output is taken across the load RC connected in the collector circuit (in

common emitter configuration).


Page 21


11.5 TRANSFORMER

Definition: - The transformer is a static electro-magnetic device that transforms

one alternating voltage (current) into another voltage (current). However, power

remains the same during the transformation. Transformers play a major role in the

transmission and distribution of ac power.

Principle: - Transformer works on the principle of mutual induction. A

transformer consists of laminated magnetic core forming the magnetic frame.

Primary and secondary coils are wound upon the two cores of the magnetic frame,

linked by the common magnetic flux. When an alternating voltage is applied across

the primary coil, a current flows in the primary coil producing magnetic flux in the

transformer core. This flux induces voltage in secondary coil.

Transformers are classified as: -

(a) Based on position of the windings with respect to core i.e.

(1) Core type transformer

(2) Shell type transformer

(b) Transformation ratio:

(1) Step up transformer

(2) Step down transformer

(a) Core & shell types: Transformer is simplest electrical machine, which

consists of windings on the laminated magnetic core. There are two

possibilities of putting up the windings on the core.

(1) Winding encircle the core in the case of core type transformer

(2) Cores encircle the windings on shell type transformer.

(b) Step up and Step down: In this Voltage transformation takes place according

to whether the Primary is high voltage coil or a low voltage coil.

(1) Lower to higher-> Step up

(2) Higher to lower-> Step down


Page 22


11.6 DIODES

- +

It is a two terminal device consisting of a P-N junction formed either of

Ge or Si crystal. The P and N type regions are referred to as anode and

cathode respectively. Commercially available diodes usually have some

means to indicate which lead is P and which lead is N.

11.7 RELAY

In this circuit a 12V magnetic relay is used. In magnetic relay, insulated

copper wire coil is used to magnetize and attract the plunger .The plunger is

normally connected to N/C terminal. A spring is connected to attract the

plunger upper side. When output is received by relay, the plunger is attracted

and the bulb glows.

Features • Utilizes the AVR

® RISC Architecture

• AVR - High-performance and Low-power RISC Architecture

- 120 Powerful Instructions - Most Single Clock Cycle Execution

- 32 x 8 General Purpose Working Registers

- Fully Static Operation

- Up to 20 MIPS Throughput at 20 MHz

• Data and Non-volatile Program and Data Memories

- 2K Bytes of In-System Self Programmable Flash

Endurance 10,000 Write/Erase Cycles

- 128 Bytes In-System Programmable EEPROM

Endurance: 100,000 Write/Erase Cycles

- 128 Bytes Internal SRAM

- Programming Lock for Flash Program and EEPROM Data Security

• Peripheral Features

- One 8-bit Timer/Counter with Separate Prescaler and Compare Mode

- One 16-bit Timer/Counter with Separate Prescaler, Compare and Capture Modes

- Four PWM Channels

- On-chip Analog Comparator

- Programmable Watchdog Timer with On-chip Oscillator

- USI - Universal Serial Interface

- Full Duplex USART

• Special Microcontroller Features

- debugWIRE On-chip Debugging

- In-System Programmable via SPI Port

- External and Internal Interrupt Sources

- Low-power Idle, Power-down, and Standby Modes

- Enhanced Power-on Reset Circuit

- Programmable Brown-out Detection Circuit

- Internal Calibrated Oscillator

• I/O and Packages

- 18 Programmable I/O Lines

- 20-pin PDIP, 20-pin SOIC, 20-pad QFN/MLF

• Operating Voltages

- 1.8 - 5.5V (ATtiny2313V)

- 2.7 - 5.5V (ATtiny2313)

• Speed Grades

- ATtiny2313V: 0 - 4 MHz @ 1.8 - 5.5V, 0 - 10 MHz @ 2.7 - 5.5V

- ATtiny2313: 0 - 10 MHz @ 2.7 - 5.5V, 0 - 20 MHz @ 4.5 - 5.5V

• Typical Power Consumption

- Active Mode

1 MHz, 1.8V: 230 µA

32 kHz, 1.8V: 20 µA (including oscillator)

- Power-down Mode

< 0.1 µA at 1.8V

8-bit

Microcontroller

with 2K Bytes

In-System

Programmable

Flash

ATtiny2313/V

Preliminary

Rev. 2543I-AVR-04/06

Pin Configurations Figure 1. Pinout ATtiny2313

PDIP/SOIC

(RESET/dW) PA2 1 20 VCC

(RXD) PD0 2 19 PB7 (UCSK/SCL/PCINT7)

(TXD) PD1 3 18 PB6 (MISO/DO/PCINT6)

(XTAL2) PA1 4 17 PB5 (MOSI/DI/SDA/PCINT5)

(XTAL1) PA0 5 16 PB4 (OC1B/PCINT4)

(CKOUT/XCK/INT0) PD2 6 15 PB3 (OC1A/PCINT3)

(INT1) PD3 7 14 PB2 (OC0A/PCINT2)

(T0) PD4 8 13 PB1 (AIN1/PCINT1)

(OC0B/T1) PD5 9 12 PB0 (AIN0/PCINT0)

GND 10 11 PD6 (ICP)

MLF

(TXD) PD1 1 15 PB5 (MOSI/DI/SDA/PCINT5)

XTAL2) PA1 2 14 PB4 (OC1B/PCINT4)

(XTAL1) PA0 3 13 PB3 (OC1A/PCINT3)

(CKOUT/XCK/INT0) PD2 4 12 PB2 (OC0A/PCINT2)

(INT1) PD3 5 11 PB1 (AIN1/PCINT1)

NOTE: Bottom pad should be soldered to ground.

Overview The ATtiny2313 is a low-power CMOS 8-bit microcontroller based on the AVR

enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the

ATtiny2313 achieves throughputs approaching 1 MIPS per MHz allowing the system

designer to optimize power consumption versus processing speed.

2

ATtiny2313/V 2543I-AVR-04/06

ATtiny2313/V

Block Diagram Figure 2. Block Diagram

XTAL1 XTAL2

PA0 - PA2

PORTA DRIVERS

VCC

GND

DATA REGISTER

PORTA

PROGRAM

COUNTER

PROGRAM

FLASH

DATA DIR.

REG. PORTA

8-BIT DATA BUS

STACK

POINTER

SRAM

INTERNAL

CALIBRATED

OSCILLATOR

INTERNAL

OSCILLATOR

WATCHDOG

TIMER

MCU CONTROL

REGISTER

MCU STATUS

REGISTER

OSCILLATOR

TIMING AND

CONTROL

ON-CHIP

DEBUGGER

RESET

INSTRUCTION

REGISTER

INSTRUCTION

DECODER

CONTROL

LINES

GENERAL

PURPOSE

REGISTER

ALU

STATUS

REGISTER

TIMER/

COUNTERS

INTERRUPT UNIT

EEPROM

USI

PROGRAMMING

LOGIC

SPI

USART

DATA REGISTER DATA DIR. DATA REGISTER DATA DIR.

PORTB REG. PORTB PORTD REG. PORTD

PORTB DRIVERS PORTD DRIVERS

PB0 - PB7 PD0 - PD6

3

2543I-AVR-04/06

ISO2-CMOS

Features

MT8870D/MT8870D-1 Integrated DTMF Receiver

ISSUE 3 May1995

• Complete DTMF Receiver

• Low power consumption

• Internal gain setting amplifier

• Adjustable guard time

• Central office quality

• Power-down mode

• Inhibit mode

• Backward compatible with

MT8870C/MT8870C-1

Applications

• Receiver system for British Telecom (BT) or

CEPT Spec (MT8870D-1)

• Paging systems

• Repeater systems/mobile radio

• Credit card systems

• Remote control

• Personal computers

• Telephone answering machine

Ordering Information

MT8870DE/DE-1 18 Pin Plastic DIP

MT8870DC/DC-1 18 Pin Ceramic DIP

MT8870DS/DS-1 18 Pin SOIC

MT8870DN/DN-1 20 Pin SSOP

MT8870DT/DT-1 20 Pin TSSOP

-40 °C to +85 °C

Description

The MT8870D/MT8870D-1 is a complete DTMF

receiver integrating both the bandsplit filter and

digital decoder functions. The filter section uses

switched capacitor techniques for high and low

group filters; the decoder uses digital counting

techniques to detect and decode all 16 DTMF tone-

pairs into a 4-bit code. External component count is

minimized by on chip provision of a differential input

amplifier, clock oscillator and latched three-state bus

interface.

VDD VSS VRef INH

PWDN Chip

Power

IN +

IN -

GS

Bias Circuit

Chip Bias

Dial Tone Filter

VRef Buffer

High Group Filter

Zero Crossing Detectors

Low Group Filter

Q1

Digital Code Detection Converter Algorithm and Latch Q2

Q3

Q4

to all Chip Clocks

St Steering

GT Logic

OSC1 OSC2 St/GT ESt STD TOE

Figure 1 - Functional Block Diagram

4-11

MT8870D/MT8870D-1 ISO2-CMOS

IN+ 1 18 VDD IN+ 1 20 VDD IN- 2 17 St/GT IN- 2 19 St/GT GS 3 16 ESt GS 3 18 ESt

VRef 4 15 StD VRef 4 17 StD

INH 5 14 Q4 INH 5 16 NC PWDN 6 13 Q3 PWDN 6 15 Q4 OSC1 7 12 Q2 NC 7 14 Q3 OSC2 8 11 Q1 OSC1 8 13 Q2

VSS 9 10 TOE OSC2 9 12 Q1 VSS 10 11 TOE

18 PIN CERDIP/PLASTIC DIP/SOIC 20 PIN SSOP/TSSOP

Figure 2 - Pin Connections

Pin Description

Pin #

18 20 Name Description

1 1 IN+ Non-Inverting Op-Amp (Input).

2 2 IN- Inverting Op-Amp (Input).

3 3 GS Gain Select. Gives access to output of front end differential amplifier for connection of feedback resistor.

4 4 VRef Reference Voltage (Output). Nominally VDD/2 is used to bias inputs at mid-rail (see Fig. 6 and Fig. 10).

5 5 INH Inhibit (Input). Logic high inhibits the detection of tones representing characters A, B, C and D. This pin input is internally pulled down.

6 6 PWDN Power Down (Input). Active high. Powers down the device and inhibits the oscillator. This pin input is internally pulled down.

7 8 OSC1 Clock (Input).

8 9 OSC2 Clock (Output). A 3.579545 MHz crystal connected between pins OSC1 and OSC2

completes the internal oscillator circuit.

9 10 VSS Ground (Input). 0V typical.

10 11 TOE Three State Output Enable (Input). Logic high enables the outputs Q1-Q4. This pin is pulled up internally.

11- 12- Q1-Q4 Three State Data (Output). When enabled by TOE, provide the code corresponding to the 14 15 last valid tone-pair received (see Table 1). When TOE is logic low, the data outputs are high

impedance.

15 17 StD Delayed Steering (Output).Presents a logic high when a received tone-pair has been

registered and the output latch updated; returns to logic low when the voltage on St/GT falls

below VTSt.

16 18 ESt Early Steering (Output). Presents a logic high once the digital algorithm has detected a

valid tone pair (signal condition). Any momentary loss of signal condition will cause ESt to return to a logic low.

17 19 St/GT Steering Input/Guard time (Output) Bidirectional. A voltage greater than VTSt detected at St causes the device to register the detected tone pair and update the output latch. A

voltage less than VTSt frees the device to accept a new tone pair. The GT output acts to reset the external steering time-constant; its state is a function of ESt and the voltage on St.

18 20 VDD Positive power supply (Input). +5V typical.

7, NC No Connection. 16

4-12

2003 2024

THRU

HIGH-VOLTAGE, HIGH-CURRENT DARLINGTON ARRAYS

Ideally suited for interfacing between low-level logic circuitry and multiple peripheral power loads, the Series ULN20xxA/L high-voltage,

1 16

2 15

3 14

4 13

5 12

6 11

7 10

8 9

Dwg. No. A-9594

Note that the ULN20xxA series (dual in-line

package) and ULN20xxL series (small-outline

IC package) are electrically identical and share a

common terminal number assignment.

ABSOLUTE MAXIMUM RATINGS

Output Voltage, VCE

(ULN200xA and ULN200xL) ... ........ 50 V

(ULN202xA and ULN202xL) ... ........ 95 V

Input Voltage, VIN ... ................................. 30 V

Continuous Output Current,

IC ... ...................................................... 500 mA

Continuous Input Current, IIN ... ............ 25 mA

Power Dissipation, PD

(one Darlington pair) ... ...................... 1.0 W

(total package) ... .................... .. See Graph

Operating Temperature Range,

TA ... .......................................... -20°C to +85°C

Storage Temperature Range,

TS ... .................................... -55°C to +150°C

high-current Darlington arrays feature continuous load current ratings to 500 mA for each of the seven drivers. At an appropriate duty cycle depending on ambient temperature and number of drivers turned ON simultaneously, typical power loads totaling over 230 W (350 mA x 7, 95 V) can be controlled. Typical loads include relays, solenoids, stepping motors, magnetic print hammers, multiplexed LED and incandescent displays, and heaters. All devices feature open-collector outputs with integral clamp diodes.

The ULN2003A/L and ULN2023A/L have series input resistors selected for operation directly with 5 V TTL or CMOS. These devices will handle numerous interface needs — particularly those beyond the capabilities of standard logic buffers.

The ULN2004A/L and ULN2024A/L have series input resistors for operation directly from 6 to 15 V CMOS or PMOS logic outputs.

The ULN2003A/L and ULN2004A/L are the standard Darlington arrays. The outputs are capable of sinking 500 mA and will withstand at least 50 V in the OFF state. Outputs may be paralleled for higher load current capability. The ULN2023A/L and ULN2024A/L will withstand 95 V in the OFF state.

These Darlington arrays are furnished in 16-pin dual in-line plastic packages (suffix “A”) and 16-lead surface-mountable SOICs (suffix “L”). All devices are pinned with outputs opposite inputs to facilitate ease of circuit board layout. All devices are rated for operation over the temperature range of -20°C to +85°C. Most (see matrix, next page) are also available for operation to -40°C; to order, change the prefix from “ULN” to “ULQ”.

FEATURES

TTL, DTL, PMOS, or CMOS-Compatible Inputs

Output Current to 500 mA

Output Voltage to 95 V

Transient-Protected Outputs

Dual In-Line Plastic Package or Small-Outline IC Package

x = digit to identify specific device. Characteristic shown applies to family of

devices with remaining digits as shown. See matrix on next page.

www.fairchildsemi.com

MC78XX/LM78XX/MC78XXA

3-Terminal 1A Positive Voltage Regulator

Features

• Output Current up to 1A

• Output Voltages of 5, 6, 8, 9, 10, 12, 15, 18, 24V •

Thermal Overload Protection

• Short Circuit Protection

• Output Transistor Safe Operating Area Protection

Internal Block Digram

Description

The MC78XX/LM78XX/MC78XXA series of three

terminal positive regulators are available in the

TO-220/D-PAK package and with several fixed output

voltages, making them useful in a wide range of

applications. Each type employs internal current limiting,

thermal shut down and safe operating area protection,

making it essentially indestructible. If adequate heat sinking

is provided, they can deliver over 1A output current.

Although designed primarily as fixed voltage regulators,

these devices can be used with external components to

obtain adjustable voltages and currents.

TO-220

1

D-PAK

1

1. Input 2. GND 3. Output

Rev. 1.0.1

©2001 Fairchild Semiconductor Corporation

1N4001 - 1N4007 Features

• Low forward voltage drop.

• High surge current capability.

DO-41 COLOR BAND DENOTES CATHODE

General Purpose Rectifiers (Glass Passivated)

Absolute Maximum Ratings* T

A = 25°C unless otherwise noted

Symbol Parameter VRRM Peak Repetitive Reverse Voltage

IF(AV) Average Rectified Forward Current, .375 " lead length @ TA = 75°C

IFSM Non-repetitive Peak Forward Surge Current

8.3 ms Single Half-Sine-Wave

Value

4001 4002 4003 4004

50 100 200 400

1.0

30

Units

4005 4006 4007

600 800 1000 V

A

A

Tstg Storage Temperature Range -55 to +175 °C

TJ Operating Junction Temperature -55 to +175 °C

*These ratings are limiting values above which the serviceability of any semiconductor device may be impaired.

Thermal Characteristics

Symbol Parameter Value Units

PD Power Dissipation 3.0 W

RθJA Thermal Resistance, Junction to Ambient 50 °C/W

Electrical Characteristics T

A = 25°C unless otherwise noted

Symbol Parameter VF Forward Voltage @ 1.0 A

Irr Maximum Full Load Reverse Current, Full Cycle TA

= 75°C

IR Reverse Current @ rated VR TA = 25°C

TA = 100

°C

CT Total Capacitance

VR = 4.0 V, f = 1.0 MHz

Device

4001 4002 4003 4004

1.1

30

5.0 500

15

Units

4005 4006 4007

V

µA

µA

µA

pF

2001 Fairchild Semiconductor Corporation 1N4001-1N4007, Rev.


Page 31


12 P.C.B. MANUFACTURING PROCESS

It is an important process in the fabrication of electronic equipment. The

design of PCBs (Printed Circuit Boards) depends on circuit requirements like

noise immunity, working frequency and voltage levels etc. High power PCBs

requires a special design strategy.

The fabrication process to the printed circuit board will determine to a

large extent the price and reliability of the equipment. A common target

aimed is the fabrication of small series of highly reliable professional quality

PCBs with low investment. The target becomes especially important for

customer tailored equipments in the area of industrial electronics.

The layout of a PCB has to incorporate all the information of the board

before one can go on the artwork preparation. This means that a concept

which clearly defines all the details of the circuit and partly defines the final

equipment, is prerequisite before the actual lay out can start. The detailed

circuit diagram is very important for the layout designer but he must also be

familiar with the design concept and with the philosophy behind the

equipment.


Page 32


PCB BOARD TYPES:

The two most popular PCB types are:

1. Single Sided Boards

The single sided PCBs are mostly used in entertainment electronics

where manufacturing costs have to be kept at a minimum. However in

industrial electronics cost factors cannot be neglected and single sided

boards should be used wherever a particular circuit can be

accommodated on such boards.

2. Double Sided Boards

Double-sided PCBs can be made with or without plated through holes.

The production of boards with plated through holes is fairly expensive.

Therefore plated through hole boards are only chosen where the circuit

complexities and density of components does not leave any other

choice.


Page 33


13. DESIGN SPECIFICATION

(I) STEPS TAKEN WHILE PREPARING CIRCUIT

13.1 PCB DESIGNING

The main purpose of printed circuit is in the routing of electric currents

and signal through a thin copper layer that is bounded firmly to an insulating

base material sometimes called the substrate. This base is manufactured with

integrally bounded layers of thin copper foil which has to be partly etched or

removed to arrive at a pre-designed pattern to suit the circuit connections or

other applications as required.

From the constructor’s point of view, the main attraction of using

PCB is its role as the mechanical support for small components. There is less

need for complicated and time consuming metal work of chassis

contraception except perhaps in providing the final enclosure. Most straight

forward circuit designs can be easily converted in to printed wiring layer the

thought required to carry out the inversion cab footed high light an possible

error that would otherwise be missed in conventional point to point wiring

.The finished project is usually neater and truly a work of art.

Actual size PCB layout for the circuit shown is drawn on the copper

board. The board is then immersed in FeCl3 solution for 12 hours. In this

process only the exposed copper portion is etched out by the solution.

Now the petrol washes out the paint and the copper layout on PCB is

rubbed with a smooth sand paper slowly and lightly such that only the oxide

layers over the Cu are removed. Now the holes are drilled at the respective

places according to component layout as shown in figure.


Page 34


13.2) LAYOUT DESIGN:

When designing the layout one should observe the minimum size

(component body length and weight). Before starting to design the layout we

need all the required components in hand so that an accurate assessment of

space can be made. Other space considerations might also be included from

case to case of mounted components over the printed circuit board or to

access path of present components.

It might be necessary to turn some components around to a different

angular position so that terminals are closer to the connections of the

components. The scale can be checked by positioning the components on the

squared paper. If any connection crosses, then one can reroute to avoid such

condition.

All common or earth lines should ideally be connected to a common

line routed around the perimeter of the layout. This will act as the ground

plane. If possible try to route the outer supply line to the ground plane. If

possible try to route the other supply lines around the opposite edge of the

layout through the center. The first set is tearing the circuit to eliminate the

crossover without altering the circuit detail in any way.

Plan the layout looking at the topside to this board. First this should be

translated inversely; later for the etching pattern large areas are recommended

to maintain good copper adhesion. It is important to bear in mind always that

copper track width must be according to the recommended minimum

dimensions and allowance must be made for increased width where

termination holes are needed. From this aspect, it can become little tricky to

negotiate the route to connect small transistors.


Page 35


There are basically two ways of copper interconnection patterns

underside the board. The first is the removal of only the amount of copper

necessary to isolate the junctions of the components to one another. The

second is to make the interconnection pattern looking more like conventional

point wiring by routing uniform width of copper from component to

component.

13.3) ETCHING PROCESS:

Etching process requires the use of chemicals. Acid resistant dishes and

running water supply. Ferric chloride is mostly used solution but other

etching materials such as ammonium per sulphate can be used. Nitric acid

can be used but in general it is not used due to poisonous fumes.

The pattern prepared is glued to the copper surface of the board using a

latex type of adhesive that can be cubed after use. The pattern is laid firmly

on the copper using a very sharp knife to cut round the pattern carefully to

remove the paper corresponding to the required copper pattern areas. Then

apply the resistant solution, which can be a kind of ink solution for the

Purpose of maintaining smooth clean outlines as far as possible. While the

board is drying, test all the components.

Before going to next stage, check the whole pattern and cross check

with the circuit diagram. Check for any free metal on the copper. The etching

bath should be in a glass or enamel disc. If using crystal of ferric- chloride


Page 36


these should be thoroughly dissolved in water to the proportion suggested.

There should be 0.5 lt. of water for 125 gm of crystal.

To prevent particles of copper hindering further etching, agitate the

solutions carefully by gently twisting or rocking the tray.

The board should not be left in the bath a moment longer than is needed

to remove just the right amount of copper. Inspite of there being a resistive

coating there is no protection against etching away through exposed copper

edges. This leads to over etching. Have running water ready so that etched

board can be removed properly and rinsed. This will halt etching

immediately.

Drilling is one of those operations that call for great care. For most

purposes a 0.5mm drill is used. Drill all holes with this size first those that

need to be larger can be easily drilled again with the appropriate larger size.

13.4) COMPONENT ASSEMBLY: -

From the greatest variety of electronic components available, which

runs into thousands of different types it, is often a perplexing task to know

which is right for a given job.


Page 37


There could be damage such as hairline crack on PCB. If there are, then

they can be repaired by soldering a short link of bare copper wire over the

affected part.

The most popular method of holding all the items is to bring the wires

far apart after they have been inserted in the appropriate holes. This will hold

the component in position ready for soldering.

Some components will be considerably larger .So it is best to start mounting

the smallest first and progressing through to the largest. Before starting, be

certain that no further drilling is likely to be necessary because access may be

impossible later.

Next will probably be the resistor, small signal diodes or other similar

size components. Some capacitors are also very small but it would be best to

fit these afterwards. When fitting each group of components mark off each

one on the circuit as it is fitted so that if we have to leave the job we know

where to recommence.

Although transistors and integrated circuits are small items there are

good reasons for leaving the soldering of these until the last step. The main

point is that these components are very sensitive to heat and if subjected to

prolonged application of the soldering iron, they could be internally

damaged.


Page 38


All the components before mounting are rubbed with sand paper so that

oxide layer is removed from the tips. Now they are mounted according to the

component layout.

13.5) SOLDERING: -

This is the operation of joining the components with PCB after this

operation the circuit will be ready to use to avoid any damage or fault during

this operation following care must be taken.

1. A longer duration contact between soldering iron bit & components

lead can exceed the temperature rating of device & cause partial or total

damage of the device. Hence before soldering we must carefully read

the maximum soldering temperature & soldering time for device.

2. The wattage of soldering iron should be selected as minimum as

permissible for that soldering place.

3. To protect the devices by leakage current of iron its bit should be

earthed properly.

4. We should select the soldering wire with proper ratio of Pb & Tn to

provide the suitable melting temperature.

5. Proper amount of good quality flux must be applied on the soldering

point to avoid dry soldering.


Page 39


14. WORKING

HOW TO USE?

We have to maintain the uninterrupted power supply to the receiver unit. The

mobile phone is connected with the control unit via DTMF decoder IC by

means of Headphone of mobile phone.

The battery of mobile phone should regularly charge and mobile phone with

control unit is kept at the pace where the receiver gets perfect signal strength.

The appliances connected are also kept connected with power supply.

WORKING: -

The user dials the mobile number of the receiver unit cell phone by his

mobile phone.

Once the connection is established by the GSM service provider the

call is automatically attended by receiving unit cell phone because of

auto answering mode.

When the call connected user presses the key from 1-7 one by one &

send control to the receiving unit.

The receiving unit cell phone is connected with DTMF decoder

MT8870 hence received DTMF signals are decoded & converted into 4

bit o/p.

The 4bit converted O/P sent to microcontroller IC where it drives

appropriate relay & hence connected appliance.

The appliances connected are being ON/OFF by pressing same keys.

We could ON/OFF all appliances at once by pressing key * & 0.


Page 40


15. APPLICATIONS

Our project is very useful in controlling home appliances. Some other

applications are listed below-

1. As a complementary option of Industrial Automation.

2. For security & other equipment control.

3. Military & Intelligence operations for switching equipments at

distance.

Advantages:

1. No need to go on field.

2. Higher reliability.

3. Cost effective.

4. Fast efficient.

5. Seven devices can be controlled by single key command

FURTHAR DEVELOPEMENT

The device can be used in very advance manner. It can develop the device

as data saving facility, remote applications & user authentication and with

smart biometric access services.


Page 41


16. CHRONOLOGY

The following steps have been followed in carrying out the project.

1. Study the books on the relevant topic.

2. Understand the working of the circuit.

3. Prepare the circuit diagram.

4. Prepare the list of components along with their specification. Estimate

the cost and procure them after carrying out market survey.

5. Plan and prepare PCB for mounting all the components.

6. Fix the components on the PCB and solder them.

7. Test the circuit for the desired performance.

8. Trace and rectify faults if any.

9. Give good finish to the unit.

10. Prepare the project report.


Page 42


17. BIBILIOGRAPHY

REFERENCE FOR TECHNICAL INFORMATION FROM FOLLOWING

BOOKS:

1. DTMF Based Remote Control System - R. Sharma, K. Kumar, and

S. Viq, IEEE International Conference ICIT, pp. 2380-2383,

December 2006.

2. A phone based Remote Controller for Home- I. Coskun and H.

Ardam IEEE Trans.Consumer , vol.44,no. 4,pp. 1291-1297,

November 1998

3. Electronics For You –

4. Integrated Electronics by Millman & Hawlkiwas.

5. Basic Electronics by J. B. Gupta

6. High Performance Printed Circuit Board – Charles Harper

7. Industrial automation Magazine

REFERENCE FOR ARTICLES & TECHNICAL INFORMATION ON

REMOTE ACCESS TERMINAL FROM FOLLOWING SITES:

http://www.google.co.in (Google search engine)

http://www.whereisdoc.com

http://www.electronicsforu.com

http://electrosofts.com/dtmf

http://www.electronicprojects.com

www.atmel.com/dyn/resources/prod_documents/doc2543.pdf

www.datasheetcatalog.net/

http://www.electronicsforu.com/

http://electrosofts.com/dtmf

http://www.electronicprojects.com/

http://www.atmel.com/dyn/resources/prod_documents/doc2543.pdf

device control using gsm mobile phone project electronics

Documents