sms based patient report from remote place1

SMS BASED PATIENT REPORT FROM REMOTE PLACE

CHAPTER-1

INTRODUCTION

The project deals with the design and development of hardware and software for

temperature and heartbeat measurement of a patient over LCD

The data which are recorded continuously in this project are Heartbeat of the patient. The

digital value read is sent to the microcontroller. The microcontroller temporarily stores this

value.

The heartbeat pulses can be seen by the doctor at regular intervals in LCD to know the

patient condition.

1.1. OBJECTIVE

The project intends to interface the microcontroller with the LCD and Heart beat

monitoring system and send the information like heartbeat pulses of the patient to the doctor’s

work station on LCD. The project uses the LCD, Heartbeat sensor and Embedded Systems to

design this application. The main objective of this project is to design a system that continuously

monitors the heartbeat of the patient and if they are likely to exceed the normal values, the

system immediately sends a message to the doctor’s LCD.

This project is a device that collects data from the sensors, codes the data into

a format that can be understood by the controlling section. This system also collects information

from the master device and implements commands that are directed by the master.


1.2 BACK GROUND OF THE PROJECT

The software application and the hardware implementation help the

microcontroller read the output of the sensors and send these values to the doctor’s mobile

whenever he sends a request to the controlling unit. The measure of efficiency is based on how

fast the microcontroller can read the sensor output values and send a message to the doctor’s

mobile whenever these parameters exceed the normal values. The system is totally designed

using LCD and embedded systems technology.

The Controlling unit has an application program to allow the

microcontroller read the sensor output values and send them to the user mobile whenever he

sends a request to the controlling unit. The performance of the design is maintained by

controlling unit.

CHAPTER-2

PROJECT DESCRIPTION


2.1 BLOCK DIAGRAM

The block diagram of the design is as shown in Fig 3.1. It consists of power supply unit,

microcontroller, GSM modem, Serial communication unit, sensor module. The brief description

of each unit is explained as follows.

Fig: Block diagram for Heartbeat Monitoring System

2.2 CIRCUIT DIAGRAM


2.3 WORKING PROCEDURE


The working of the project goes like this: The temperature and heartbeat of the patient

will be monitored continuously and the status of the patient will be monitored and sent to the

doctor wherever he may be.

Thus, the two values, the temperature and the heartbeat pulse will be sent to the doctor

who knows the entire health conditions of the patient. Thus, to send this data, we are using the

wireless technology, GSM. When the monitoring system sends a message to the doctor’s mobile,

even this system should have a device which can send or receive the messages from/to the

doctor. The device we are using is the GSM modem. The modem is exactly similar to our mobile

phones. Even the modem requires a SIM card to communicate with the outside world. The

modem will be interfaced with the microcontroller through serial interface.

The data which are monitored continuously in this project are Temperature and Heartbeat

of the patient. The analog quantities are taken and converted into corresponding digital values

using a single channel ADC. This converted digital value is sent to the microcontroller. The

microcontroller temporarily stores this value.

The doctor can read the temperature and heartbeat value whenever he wishes to. The

doctor can take care of the patient’s condition wherever he may be. The doctor has to send

predefined messages to the modem to retrieve the data. The modem receives the predefined

messages and intimates the same to the microcontroller. Now, it is the job of the microcontroller

to read the value, process it and send the requested value to the doctor’s mobile. The user can

read the updated data whenever he reads the predefined messages to the modem. These values

can also be displayed on the LCD.

CHAPTER 3

MICROCONTROLLER


3.1. A brief history of the 8051 family:

In 1981, Intel Corporation introduced an 8-bit microcontroller called the 8051. This

microcontroller had 128 bytes of RAM,4K bytes of on- chip ROM, two timers, one serial port,

and four ports(each 8-bit wide) all on a single chip. At the time it is also referred to as a “system

on chip.” This is an 8-bit processor, meaning that the CPU can work on only 8 bits of data at a

time. Data larger than 8 bits has to be broken into 8 bit pieces to be processed by the CPU. The

8051 has a total of four I/O ports, each 8-bit wide.

The 8051 became widely popular after Intel allowed other manufactures to make and

market any flavors of the 8051 they please with the condition that they remain code-compatible

with the 8051. This led to many versions of the 8051 with different speeds and amounts of on-

chip ROM marketed by more than half a dozen manufacturers. It is important to note that

although there are different flavors of the 8051 in terms of speed and amount of on-chip ROM,

they are all compatible with the original 8051 as far as the instructions are concerned. This

means that if you write your program for one, it will run on any of them regardless of the

manufacturer.

“The 8051 is the original member of the 8051 family. Intel refers to it as MCS-51.”

The Microcontroller AT89c51 is from Atmel Corporation. It has a wide collection of 8051

chips, as shown below. The AT89C51 is a popular and inexpensive chip used in many small

projects. It has 4K bytes of flash ROM. Notice that AT89C51-12PC, where “C” before the 51

stands for CMOS, which has low power consumption, “12” indicates 12MHz, “P” is for plastic

DIP package, and another “C” is for commercial.

3.2 FEATURES

Compatible with MCS-51 Products

8K Bytes of In-System Reprogrammable Flash Memory


Fully Static Operation: 0 Hz to 33 MHz

Three-level Program Memory Lock

256 x 8-bit Internal RAM

32 Programmable I/O Lines

Three 16-bit Timer/Counters

Eight Interrupt Sources

Programmable Serial Channel

Low-power Idle and Power-down Modes

4.0V to 5.5V Operating Range

Full Duplex UART Serial Channel

Interrupt Recovery from Power-down Mode

Watchdog Timer

Dual Data Pointer

Power-off Flag

Fast Programming Time

Flexible ISP Programming (Byte and Page Mode

3.3 PIN DIAGRAM:


FIG PIN DIAGRAM OF 89S52 IC

3.4 PIN DESCRIPTION

VCCSupply voltage.

GNDGround.

Port 0 Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can

sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high

impedance inputs. Port 0 can also be configured to be the multiplexed low order address/data bus

during accesses to external program and data memory. In this mode, P0 has internal pull-ups.

Port 0 also receives the code bytes during Flash programming and outputs the code bytes during

program verification.

External pull-ups are required during program verification.


Port 1 Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1 output

buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high

by the internal pull-ups and can be used as inputs. As inputs, Port 1 pins that are externally being

pulled low will source current (IIL) because of the internal pull-ups. In addition, P1.0 and P1.1

can be configured to be the timer/counter 2 external count input (P1.0/T2) and the timer/counter

2 trigger input (P1.1/T2EX), respectively, as shown in the following table. Port 1 also receives

the low-order address bytes during Flash programming and verification.

Port 2

Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 2 output



pulled low will source current (IIL) because of the internal pull-ups. Port 2 emits the high-order

address byte during fetches from external program memory and during accesses to external data

memory that uses 16-bit addresses (MOVX @ DPTR). In this application, Port 2 uses strong

internal pull-ups when emitting 1s. During accesses to external data memory that uses 8-bit

addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register. Port 2

also receives the high-order address bits and some control signals during Flash programming and

verification.

Port 3


Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output



pulled low will source current (IIL) because of the pull-ups. Port 3 also serves the functions of

various special features of the AT89S52, as shown in the following table. Port 3 also receives

some control signals for Flash programming and verification.

RST Reset input. A high on this pin for two machine cycles while the oscillator is

running resets the device. This pin drives High for 96 oscillator periods after the Watchdog times

out. The DISRTO bit in SFR AUXR (address 8EH) can be used to disable this feature. In the

default state of bit DISRTO, the RESET HIGH out feature is enabled. ALE/PROG Address

Latch Enable (ALE) is an output pulse for latching the low byte of the address during accesses to

external memory. This pin is also the program pulse input (PROG) during Flash programming.

In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be

used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped

during each access to external data memory. If desired, ALE operation can be disabled by setting

bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC

instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if

the microcontroller is in external execution mode.

PSEN


Program Store Enable (PSEN) is the read strobe to external program memory.

When the AT89S52 is executing code from external program memory, PSEN is activated twice

each machine cycle, except that two PSEN activations are skipped during each access to external

data memory.

EA/VPP

External Access Enable. EA must be strapped to GND in order to enable the device

to fetch code from external program memory locations starting at 0000H up to FFFFH. Note,

however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be

strapped to VCC for internal program executions. This pin also receives the 12-volt

programming enable voltage

(VPP) during Flash programming.

XTAL1

Input to the inverting oscillator amplifier and input to theInternal clock operating circuit.

XTAL2

Output from the inverting oscillator amplifier.

CHAPTER 4

POWER SUPPLY

All digital circuits require regulated power supply. In this article we are going to learn how to get

a regulated positive supply from the mains supply.


Figure shows the basic block diagram of a fixed regulated power supply. Let us go through each

block.

4.1 TRANSFORMER

A transformer consists of two coils also called as “WINDINGS” namely PRIMARY &

SECONDARY. They are linked together through inductively coupled electrical conductors also

called as CORE. A changing current in the primary causes a change in the Magnetic Field in the

core & this in turn induces an alternating voltage in the secondary coil. If load is applied to the

secondary then an alternating current will flow through the load. If we consider an ideal

condition then all the energy from the primary circuit will be transferred to the secondary circuit

through the magnetic field.

So


The secondary voltage of the transformer depends on the number of turns in the Primary as well as in the

secondary.

4.2 RECTIFIER

A rectifier is a device that converts an AC signal into DC signal. For rectification purpose we use

a diode, a diode is a device that allows current to pass only in one direction i.e. when the anode

of the diode is positive with respect to the cathode also called as forward biased condition &

blocks current in the reversed biased condition.

Rectifier can be classified as follows:

1) Half Wave rectifier.

This is the simplest type of rectifier as you can see in the diagram a half wave rectifier consists

of only one diode. When an AC signal is applied to it during the positive half cycle the diode is

forward biased & current flows through it. But during the negative half cycle diode is reverse

biased & no current flows through it. Since only one half of the input reaches the output, it is

very inefficient to be used in power supplies.

2) Full wave rectifier.


Half wave rectifier is quite simple but it is very inefficient, for greater efficiency we would like

to use both the half cycles of the AC signal. This can be achieved by using a center tapped

transformer i.e. we would have to double the size of secondary winding & provide connection to

the center. So during the positive half cycle diode D1 conducts & D2 is in reverse biased

condition. During the negative half cycle diode D2 conducts & D1 is reverse biased. Thus we get

both the half cycles across the load.

One of the disadvantages of Full Wave Rectifier design is the necessity of using a center tapped

transformer, thus increasing the size & cost of the circuit. This can be avoided by using the Full

Wave Bridge Rectifier.

3) Bridge Rectifier.


As the name suggests it converts the full wave i.e. both the positive & the negative half cycle

into DC thus it is much more efficient than Half Wave Rectifier & that too without using a center

tapped transformer thus much more cost effective than Full Wave Rectifier. Full Bridge Wave

Rectifier consists of four diodes namely D1, D2, D3 and D4. During the positive half cycle

diodes D1 & D4 conduct whereas in the negative half cycle diodes D2 & D3 conduct thus the

diodes keep switching the transformer connections so we get positive half cycles in the output.

If we use a center tapped transformer for a bridge rectifier we can get both positive & negative

half cycles which can thus be used for generating fixed positive & fixed negative voltages.

4.3 VOLTAGE REGULATOR

A Voltage regulator is a device which converts varying input voltage into a constant regulated

output voltage. Voltage regulator can be of two types

1) Linear Voltage Regulator

Also called as Resistive Voltage regulator because they dissipate the excessive voltage

resistively as heat.

2) Switching Regulators.

They regulate the output voltage by switching the Current ON/OFF very rapidly. Since their

output is either ON or OFF it dissipates very low power thus achieving higher efficiency as

compared to linear voltage regulators. But they are more complex & generate high noise due to


their switching action. For low level of output power switching regulators tend to be costly but

for higher output wattage they are much cheaper than linear regulators.

The most commonly available Linear Positive Voltage Regulators are the 78XX series where the

XX indicates the output voltage. And 79XX series is for Negative Voltage Regulators.

After filtering the rectifier output the signal is given to a voltage regulator. The maximum input

voltage that can be applied at the input is 35V.Normally there is a 2-3 Volts drop across the

regulator so the input voltage should be at least 2-3 Volts higher than the output voltage. If the

input voltage gets below the Vmin of the regulator due to the ripple voltage or due to any other

reason the voltage regulator will not be able to produce the correct regulated voltage.

3 Circuit diagram:

Fig 2.3. Circuit Diagram of power supply

IC 7805:

7805 is an integrated three-terminal positive fixed linear voltage regulator. It supports an input

voltage of 10 volts to 35 volts and output voltage of 5 volts. It has a current rating of 1 amp

although lower current models are available. Its output voltage is fixed at 5.0V. The 7805 also


has a built-in current limiter as a safety feature. 7805 is manufactured by many companies,

including National Semiconductors and Fairchild Semiconductors.

The 7805 will automatically reduce output current if it gets too hot.The last two digits represent

the voltage; for instance, the 7812 is a 12-volt regulator. The 78xx series of regulators is

designed to work in complement with the 79xx series of negative voltage regulators in systems

that provide both positive and negative regulated voltages, since the 78xx series can't regulate

negative voltages in such a system.

The 7805 & 78 is one of the most common and well-known of the 78xx series regulators, as it's

small component count and medium-power regulated 5V make it useful for powering TTL

devices.

Table. Specifications of IC7805

SPECIFICATIONS IC 7805

Vout 5V

Vein - Vout Difference 5V - 20V

Operation Ambient Temp 0 - 125°C

Output Imax 1A


CHAPTER-5

SENSORS

The sensors used in this project are Heartbeat and Temperature sensor. The

output of temperature sensor is given to the ADC so as to convert the analog value into digital

data and then give it to the microcontroller. The Heartbeat sensor used is basically a LED and

LDR arrangement.

5.1 HERT BEAT SENSOR


LED and LDR arrangement

The Heartbeat sensor used in this project is basically a LED and LDR arrangement.

The LED used in this arrangement is a high intensity LED.

Heart beat is sensed by using a high intensity type LED and LDR. The finger is

placed between the LED and LDR. As sensor, a photo diode or a photo transistor can be used.

The skin may be illuminated with visible (red) using transmitted or reflected light for detection.

The very small changes in reflectivity or in transmittance caused by the varying blood content of

human tissue are almost invisible. Various noise sources may produce disturbance signals with

amplitudes equal or even higher than the amplitude of the pulse signal. Valid pulse measurement

therefore requires extensive preprocessing of the raw signal.

The setup described here uses a red LED for transmitted light illumination and

a LDR as detector. With only slight changes in the preamplifier circuit the same hardware and

software could be used with other illumination and detection concepts. These values are sent to

the ADC for conversion of analog to digital and then sent to the microcontroller.

5.2 LM35 TEMPERATURE SENSOR


LM35 converts temperature value into electrical signals. LM35 series sensors are

precision integrated-circuit temperature sensors whose output voltage is linearly proportional to

the Celsius temperature. The LM35 requires no external calibration since it is internally

calibrated. . The LM35 does not require any external calibration or trimming to provide typical

accuracies of ±1⁄4°C at room temperature and ±3⁄4°C over a full −55 to +150°C temperature

range.

The LM35’s low output impedance, linear output, and precise inherent calibration make

interfacing to readout or control circuitry especially easy. It can be used with single power

supplies, or with plus and minus supplies. As it draws only 60 μA from its supply, it has very

low self-heating, less than 0.1°C in still air.

5.2.1 FEATURES

Calibrated directly in ° Celsius (Centigrade)

Linear + 10.0 mV/°C scale factor

0.5°C accuracy guaranteed (at +25°C)

Rated for full −55° to +150°C range

Suitable for remote applications

Low cost due to wafer-level trimming

Operates from 4 to 30 volts

Less than 60 μA current drain

Low self-heating, 0.08°C in still air

Nonlinearity only ±1⁄4°C typical

Low impedance output, 0.1 W for 1 mA load


The characteristic of this LM35 sensor is:

For each degree of centigrade temperature it outputs 10milli volts.

CHAPTER-6

ANALOG TO DIGITAL CONVERTER

Analog-to-digital converters are among the most widely used devices for data

acquisition. Digital systems use binary values, but in the physical world everything is continuous

i.e., analog values. Temperature, pressure (wind or liquid), humidity and velocity are the

physical analog quantities. These physical quantities are to be converted into digital values for

further processing. One such device to convert these physical quantities into electrical signals is

sensor. Sensors for temperature, pressure, humidity, light and many other natural quantities

produce an output that is voltage or current.


Thus, an analog-to-digital converter is needed to convert these electrical

signals into digital values so that the microcontroller can read and process them. An ADC has an

n-bit resolution where n can be 8,10,12,16 or even 24 bits. The higher resolution ADC provides a

smaller step size, where step size is the smallest change that can be detected by an ADC. In

addition to resolution, conversion time is another major factor in judging an ADC. Conversion

time is defined as the time it takes the ADC to convert the analog input to a digital number.

6.1 PIN DIAGRAM

ADC0804:

The ADC chip that is used in this project is ADC0804. The ADC0804 IC is an

8-bit parallel ADC in the family of the ADC0800 series from National Semiconductor. It works

with +5 volts and has a resolution of 8 bits. In the ADC0804, the conversion time varies

depending on the clocking signals applied to the CLK IN pin, but it cannot be faster than 110µs.

6.2 PIN DESCRIPTION

CS (Chip select)

Chip select is an active low input used to activate the ADC0804 chip. To access the ADC0804,

this pin must be low.

RD (read)


This is an input signal and is active low. ADC converts the analog input to its binary equivalent

and holds it in an internal register. RD is used to get the data out of ADC0804 chip. When CS=0,

if a high-to-low pulse is applied to the RD pin, the 8-bit digital output shows up at the D0-D7

data pins.

WR (write)

This is an active low input used to inform the ADC0804 to start the conversion process.

If CS=0 when WR makes a low-to-high transition, the ADC0804 starts converting the analog

input value Vin to an 8-bit digital value. The amount of time it takes to convert varies depending

on the CLK IN and CLK R values.

CLK IN and CLK R

CLK IN is an input pin connected to an external clock source when an external clock is

used for timing. However, the 804 has an internal clock generator. To use the internal clock

generator of the ADC0804, the CLK IN and CLK R are connected to a capacitor and a resistor.

In that case, the clock frequency is determined by the equation:

f = 1/ (1.1RC)

Typical values are R=10K ohms and C= 150 pf. Substituting in the above equation, the

frequency is calculated as 606 kHz. Thus, the conversion time is 110µs.

INTR

This is an output pin and is active low. It is a normally high pin and when the conversion is

finished, it goes low to signal the CPU that the converted data is ready to be picked up. After


INTR goes low, the CS pin is made low i.e., CS=0 and send a high-to-low pulse to the RD pin to

get the data out of the ADC0804 chip.

Vin(+) and Vin(-)

These are the differential analog inputs where Vin=Vin(+) – Vin(-). The Vin(-) pin is connected

to ground and the Vin(+) pin is used as the analog input to be converted to digital.

Vcc

This is the +5 volt power supply. It is also used as a reference voltage when the Vref/2 input (pin

9) is open.

Vref/2

Pin 9 is an input voltage used for the reference voltage. If this pin is open, the analog input

voltage for the ADC0804 is in the range of 0 to 5 volts.Vref/2 is used to implement analog input

voltages other than 0.5V. i.e., if the analog input range needs to be 0 to 4 volts, Vref/2 is

connected to 2 volts.

D0-D7

D0-D7 (D7 is the MSB) are the digital data output pins since ADC0804 is a

parallel ADC chip. To calculate the output voltage, the below equation is used:

Dout = Vin/ (step size)

where Dout = digital data output pins (in decimal) and Vin = analog input value

Analog ground and Digital ground

These are the input pins providing the ground for both the analog signal and the

digital signal. Analog ground is connected to the ground of the analog Vin while digital ground

is connected to the ground of the Vcc pin.


Clock source for ADC0804:

The speed at which an analog input is converted to the digital output depends on the

speed of the CLK input. According to the ADC0804 datasheets, the typical operating frequency

is approximately 640 kHz at 5 volts.

ADC interface with Microcontroller:


CHAPTER-7

LIQUID CRYSTAL DISPLAY

LCD stands for Liquid Crystal Display. LCD is finding wide spread use replacing LEDs (seven

segment LEDs or other multi segment LEDs) because of the following reasons:

1. The declining prices of LCDs.

2. The ability to display numbers, characters and graphics. This is in contrast to LEDs,

which are limited to numbers and a few characters.

3. Incorporation of a refreshing controller into the LCD, thereby relieving the CPU of the

task of refreshing the LCD. In contrast, the LED must be refreshed by the CPU to keep

displaying the data.

4. Ease of programming for characters and graphics.

7.1 LCD SCREEN

LCD screen consists of two lines with 16 characters each. Each character consists of 5x7 dot

matrix. Contrast on display depends on the power supply voltage and whether messages are

displayed in one or two lines. For that reason, variable voltage 0-Vdd is applied on pin marked as


Vee. Trimmer potentiometer is usually used for that purpose. Some versions of displays have

built in backlight (blue or green diodes). When used during operating, a resistor for current

limitation should be used (like with any LE diode).

LCD Connection

Depending on how many lines are used for connection to the microcontroller, there are 8-bit and

4-bit LCD modes. The appropriate mode is determined at the beginning of the process in a phase

called “initialization”. In the first case, the data are transferred through outputs D0-D7 as it has

been already explained. In case of 4-bit LED mode, for the sake of saving valuable I/O pins of

the microcontroller, there are only 4 higher bits (D4-D7) used for communication, while other

may be left unconnected.


Consequently, each data is sent to LCD in two steps: four higher bits are sent first (that normally

would be sent through lines D4-D7), four lower bits are sent afterwards. With the help of

initialization, LCD will correctly connect and interpret each data received.

Besides, with regards to the fact that data are rarely read from LCD (data mainly are transferred

from microcontroller to LCD) one more I/O pin may be saved by simple connecting R/W pin to

the Ground. Such saving has its price.

Even though message displaying will be normally performed, it will not be possible to read from

busy flag since it is not possible to read from display.

7.2 LCD INTERFACING WITH 8051


CHAPTER-8

RS-232 AND MAX-232

8.1 RS 232:

RS-232 is simple, universal, well understood and supported but it has some serious

shortcomings as a data interface. The standards to 256kbps or less and line lengths of 15M (50 ft)

or less but today we see high speed ports on our home PC running very high speeds and with

high quality cable maxim distance has increased greatly. The rule of thumb for the length a data

cable depends on speed of the data, quality of the cable.

.

Sub-D15 Male Sub-D15 Female

This is a standard 9 to 25 pin cable layout for async data on a PC AT serial cable

Description Signal 9-pin DTE 25-pin DCE Source DTE or DCE

Carrier Detect CD 1 8 from Modem

Receive Data RD 2 3 from Modem

Transmit Data TD 3 2 from Terminal/Computer


Data Terminal Ready DTR 4 20 from Terminal/Computer

Signal Ground SG 5 7 from Modem

Data Set Ready DSR 6 6 from Modem

Request to Send RTS 7 4 from Terminal/Computer

Clear to Send CTS 8 5 from Modem

Ring Indicator RI 9 22 from Modem


8.2 MAX 232:

DESCRIPTION:

The MAX232 device is a dual driver/receiver that includes a capacitive voltage

generator to supply EIA-232 voltage levels from a single 5-V supply. Each receiver converts EIA-232

inputs to 5-V TTL/CMOS levels. These receivers have a typical threshold of 1.3 V and a typical

hysteresis of 0.5 V, and can accept 30-V inputs. Each driver converts TTL/CMOS input levels into

EIA-232 levels. The driver, receiver, and voltage-generator functions are available as cells in the Texas.

8.2.1 FEATURES:

Operates With Single 5-V Power Supply

Lin Bi CMOS Technology

Two Drivers and Two Receivers

30-V Input Levels

Low Supply Current . . . 8 mA Typical

Meets or Exceeds TIA/EIA-232-F and ITU


Recommendation V.28

8.2.2 APPLICATIONS:

TIA/EIA-232-F

Battery-Powered Systems

Terminals

Modems

Computers

ESD Protection Exceeds 2000 V Per

MIL-STD-883, Method 3015

Package Options Include Plastic

Small-Outline (D, DW) Packages and

Standard Plastic (N) DIPs

Absolute maximum ratings

Input supply voltage range, VCC : – 0.3 V to 6 V

Positive output supply voltage range: VS+ VCC – 0.3 V to 15 V

Negative output supply voltage range: VS––0.3 V to –15 V

Input voltage range, VI: Driver:–0.3 V to VCC + 0.3 V

Receiver: 30 V


Output voltage range, VO: T1OUT, T2OUT VS –0.3 V to VS+ + 0.3 V

R1OUT, R2OUT : –0.3 V to VCC + 0.3 V

Short-circuit duration: T1OUT, T2OUT: Unlimited

Package thermal impedance, D package :113C/W

DW package : 105C/W

N package : 78C/W

Storage temperature range, Tstg : –65C to 150C

Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds: 260C

Stresses beyond those listed under “absolute maximum ratings” may cause permanent

damage to the device. These are stress ratings only, and functional operation of the device at

these or any other conditions beyond those indicated under “recommended operating conditions”

is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect

device reliability. NOTE 1: All voltage values are with respect

to network ground terminal.2. The package thermal impedance is calculated in accordance with

JESD 51, except for through-hole packages, which use a trace length of zero description


8.2.3. MAX 232 Interfacing with RS232 and 89C51 microcontroller:

The MAX232 device is a dual driver/receiver that includes a capacitive voltage

generator to supply EIA-232 voltage levels from a single 5-V supply. Each receiver converts

EIA-232 inputs to 5-V TTL/CMOS levels. These receivers have a typical threshold of 1.3 V and

a typical hysterics of 0.5 V, and can accept 30-V inputs. Each driver converts TTL/CMOS

input levels into EIA-232 levels. The driver, receiver, and voltage-generator functions are

available as cells in the Texas.

CHAPTER-9

GSM MODEM

9.1 THEORY

Unlike mobile phones, a GSM modem doesn’t have a keypad and display to interact with. It just accepts certain commands through a serial interface and acknowledges for those. These commands are called as AT commands. There are a list of AT commands to instruct the modem to perform its functions. Every command starts with "AT". That’s why they are called as AT commands. AT stands for attention.


SMS Related AT Commands

AT It is used to test the connection.

AT+CMGF=1It is used to instruct the modem to operate in text mode. AT+CMGF=0 will instruct the modem to operate in PDU mode.

AT+CMGS="mobile number"

It is used to send a text message. It accepts the recipient mobile number. As soon as this command is accepted the modem waits for the message content. The text message has to be sent sequentially and terminated by the char 0x1A.

AT+CMGW="mobile number"

It is used to store a message in the memory. After execution it returns an index for the message stored. Eg: AT+CMGW=1 . Here 1 is the


index for the saved message. Later this index is used to process the message like deleting it or forwarding to the recipient number.

AT+CMGD=2It is used to delete a message from the storage. The index of the stored message is used to delete it. Above command deletes the message with index 2.

In our simple project, the program waits for the mobile number to be entered through the keyboard. When a ten digit mobile number is provided, the program instructs the modem to send the text message using a sequence of AT commands

Testing your GSM modem

The GSM modem can be tested by connecting it with a PC. The modem is equipped with a RS232 cable. Just use a Serial to USB converter and connect it with the PC.

Now you can proceed with sending the commands to the modem using any serial communication program like Hyperterminal, minicom etc. Ensure the serial paramters are configured to 8N1 and the baudrate is set to 9600bps.

For each command you send the modem acknowledges with a message. Example: Just try sending "AT" to the modem. It sends back a result code "OK" which states that the modem is responding. If it’s not working fine, it sends "ERROR".

APPLICATIONS

1. All the parameters can be viewed on the mobile phone.

2. Most reliable.

3. Cost effective.

4. Supports innumerable sensors to the system.


RESULTS AND CONCLUSION

Results

Assemble the circuit on the PCB as shown in Fig 5.1. After assembling the circuit on the

PCB, check it for proper connections before switching on the power supply.

Conclusion

The implementation of Heartbeat Monitoring System using GSM is done successfully. The

communication is properly done without any interference between different modules in the design.

Design is done to meet all the specifications and requirements. Software tools like Keil Uvision

Simulator, Proload to dump the source code into the microcontroller, Orcad Lite for the schematic

diagram have been used to develop the software code before realizing the hardware.


The performance of the system is more efficient. Continuously reading the output from

the sensors and pass the data to the doctor’s mobile whenever the read values exceed the normal

values or whenever the doctor sends a request to the controlling unit is the main job carried out

by the microcontroller. The mechanism is controlled by the microcontroller.

Circuit is implemented in Orcad and implemented on the microcontroller board. The performance

has been verified both in software simulator and hardware design. The total circuit is completely verified

functionally and is following the application software.

It can be concluded that the design implemented in the present work provide portability, flexibility and

the data transmission is also done with low power consumption.

REFRENCES AND BIBLOGRAPHY

Muhammad Ali Mazidi , Janice Gillispie Mazidi, Rolin D. Mckinlay.

Second edition, “THE 8051 MICROCONTROLLER AND EMBEDDED SYSTEM”

K. J. Ayala. Third edition, “The 8051 MICROCONTROLLER”

General information about electronic voting machine

www.eci.gov.in

www.eci.gov.in/faq/evm.asp

www.eci.gov.in/Audio_VideoClips/presentation/EVM.ppt

www.rajasthan.net/election/guide/evm.htm

http://www.rajasthan.net/election/guide/evm.htm

http://www.eci.gov.in/Audio_VideoClips/presentation/EVM.ppt

http://www.eci.gov.in/faq/evm.asp

http://www.eci.gov.in/


www.indian-elections.com/electoralsystem/electricvotingmachine.html

Tutorial on microcontroller:

www.8051projects.net/microcontroller_tutorials/

Tutorial on LCD:

www.8051projects.net/lcd-interfacing/

APPENDIX

Keil Compiler:

Keil compiler is software used where the machine language code is written and compiled.

After compilation, the machine source code is converted into hex code which is to be dumped

into the microcontroller for further processing. Keil compiler also supports C language code.

http://www.8051projects.net/lcd-interfacing/

http://www.indian-elections.com/electoralsystem/electricvotingmachine.html


Fig Compilation of source Code


Fig Run the compiled program

Proload:

Proload is software which accepts only hex files. Once the machine code is converted

into hex code, that hex code has to be dumped into the microcontroller and this is done by the

Proload. Proload is a programmer which itself contains a microcontroller in it other than the one

which is to be programmed. This microcontroller has a program in it written in such a way that it

accepts the hex file from the Keil compiler and dumps this hex file into the microcontroller

which is to be programmed. As the Proload programmer kit requires power supply to be

operated, this power supply is given from the power supply circuit designed above. It should be

noted that this programmer kit contains a power supply section in the board itself but in order to

switch on that power supply, a source is required. Thus this is accomplished from the power

supply board with an output of 12volts.


Fig Atmel AT89C2051 Device programmer

Features

Supports major Atmel 89 series devices

Auto Identify connected hardware and devices

Error checking and verification in-built

Lock of programs in chip supported to prevent program copying

20 and 40 pin ZIF socket on-board

Auto Erase before writing and Auto Verify after writing

Informative status bar and access to latest programmed file

Simple and Easy to use

Works on 57600 speed

Description

It is simple to use and low cost, yet powerful flash microcontroller programmer for the

Atmel 89 series. It will Program, Read and Verify Code Data, Write Lock Bits, Erase and Blank

Check. All fuse and lock bits are programmable. This programmer has intelligent onboard

firmware and connects to the serial port. It can be used with any type of computer and requires

no special hardware. All that is needed is a serial communication ports which all computers

have.

All devices have signature bytes that the programmer reads to automatically identify the

chip. No need to select the device type, just plug it in and go! All devices also have a number of


lock bits to provide various levels of software and programming protection. These lock bits are

fully programmable using this programmer. Lock bits are useful to protect the program to be

read back from microcontroller only allowing erase to reprogram the microcontroller. The

programmer connects to a host computer using a standard RS232 serial port. All the

programming 'intelligence' is built into the programmer so you do not need any special hardware

to run it. Programmer comes with window based software for easy programming of the devices.

Programming Software

Computer side software called 'Proload V4.1' is executed that accepts the Intel HEX format file

generated from compiler to be sent to target microcontroller. It auto detects the hardware

connected to the serial port. It also auto detects the chip inserted and bytes used. Software is

developed in Delphi 7 and requires no overhead of any external DLL.


Fig Writing the programs bytes onto the microcontroller

Project source code

Main code:

#include<reg51.h>

#include"lcddisplay.h"

#include"UART.h"


#include"eeprom.h"

#include<string.h>

sbit temp = P2^2;

sbit panic = P2^3;

sbit finger = P2^7;

//void long_delay();

unsigned char mobilenum1[10];

unsigned char rec[20];

unsigned char str[10],mobilenum[11];

code unsigned char str1[]={"OK"};

unsigned char l,s,n,a,b,i,count,j,jjj,hb=68;

void main()

{

temp=panic=finger=1;

lcd_int();

USART_int();

lcdcmd(0x84);

msgdisplay(" welcome " );


delay(1000);

lcdcmd(0x01);

msgdisplay("searching for");

lcdcmd(0xc0);

msgdisplay("GSM modem");

delay(100);

send_to_modem("ate0"); //to avoid echo signals,

enter();

send_to_modem("at"); // TO CHECKING GSM MODEM...

enter();

for(s=0;s<5;s++) // Here we are waiting for data whitch is sending by GSM modem

{ // to checking wether the GSM modem connected to system or

while(RI==0); // not.

str[s]=SBUF;

RI=0;

}

/*str[s]='\0';

lcdcmd(0x01);

msgdisplay1(str);

long_delay();


n=strcmp(str3,str1);

if(n)

goto again; // GSM modem if those are matching then following messages

else

{*/ // are displaying on LCD.

lcdcmd(0x01);

msgdisplay("SYSTEM");

lcdcmd(0xc3);

msgdisplay("CONNECTED");

// }

send_to_modem("at+cmgf=1");

enter();

send_to_modem("at+cmgd=1");

enter();


enter();


enter();

RI=0;


lcdcmd(0x01);

msgdisplay(mobilenum);

st:delay(2500);

while(RI==1)

{

RI=0;

delay(100);

}

lcdcmd(0x01);

msgdisplay("patient ");

lcdcmd(0xc0);

msgdisplay("monitoring systm");

while(RI==1);

while(1)

{


hb=hb+1;

if(hb==80)

hb=69;

if(finger==0)

{

delay(500);

if((finger==0)&&(hb>79))

{

lcdcmd(0x1);

msgdisplay(" high heartbeat");

send_to_modem("at+cmgs=");

ch_send_to_modem('"');

send_to_modem(mobilenum);


enter();

send_to_modem("emergency alert for patient xyz..");

ch_send_to_modem(0x1a);

enter();


while(RI==0);

a=SBUF;

RI=0;

if(a==13)

{

lcdcmd(0x01);

msgdisplay("message sent");

goto st;

}

}

else

{

lcdcmd(0x01);

msgdisplay("heart beat: ");

lcddata((hb/10)+48);

lcddata((hb%10)+48);

delay(500);

while(finger==0);

}

goto st;

}

if(temp==0)


{

resend:

lcdcmd(0x01);

msgdisplay("over temp");

lcdcmd(0xc3);

msgdisplay("sending msg");





enter();

send_to_modem("abnormal temerature from room1 ");


enter();

while(RI==0);

a=SBUF;

RI=0;

while(RI==0);

b=SBUF;

RI=0;

if(a==13)

{


lcdcmd(0x01);

msgdisplay("message sent ");

goto st;

}

else

{

delay(2000);

goto resend;

}

}

if(panic==0)

{

resend1:

lcdcmd(0x01);

msgdisplay("emergency alert from room1");

lcdcmd(0xc3);

msgdisplay("sending msg");





enter();


send_to_modem("emergency alert ");


enter();

while(RI==0);

a=SBUF;

RI=0;

if(a==13)

{

lcdcmd(0x01);

msgdisplay("message sent");

goto st;

}

else

{

delay(2000);

goto resend1;

}

}

}

}


}

}

}

LCD CODE:

#include<reg51.h>

#define lcd_data P2

#define lcd_cont() ((lcd_en=1),(delay(3)),(lcd_en=0))

sbit lcd_rs = P2^1;


sbit lcd_en = P2^0;

void lcd_init(void);

void lcdcmd(unsigned char value);

void lcddata(unsigned char value);

void msgdisplay(unsigned char b[]);

void delay(unsigned int value);

void lcd_init(void)

{

lcdcmd(0x02);

lcdcmd(0x02);

lcdcmd(0x02);

lcdcmd(0x28);

lcdcmd(0x28);

lcdcmd(0x28);

lcdcmd(0x0c);

lcdcmd(0x06);

lcdcmd(0x01);

}

void lcdcmd(unsigned char value) // LCD COMMAND

{

lcd_data=value&(0xf0);

lcd_rs=0;

lcd_cont();


lcd_data=((value<<4)&(0xf0));

lcd_rs=0;

lcd_cont();

void lcddata(unsigned char value)

{

lcd_data=value&(0xf0);

lcd_rs=1;

lcd_cont();

delay(3);

lcd_data=((value<<4)&(0xf0));

lcd_rs=1;

lcd_cont();

delay(3);

}

void msgdisplay(unsigned char b[])

{

unsigned char s,count=0;

for(s=0;b[s]!='\0';s++)

{

lcddata(b[s]);

}

}


void delay(unsigned int value)

{

unsigned int x,y;

for(x=0;x<100;x++)

for(y=0;y<value;y++);

}

SERIAL COMMUNICATION CODE:

#include<reg51.h>

void UART_init();

void send_to_modem(char*);

void enter();

void send(char);

void ch_send_to_modem(char*);

void UART_init()

{

SCON = 0x50;

TMOD = 0x20;

TH1 = 0xFD;

TR1 = 1;

}

void send_to_modem(char *s)

{


while(*s != '\0')

{

send(*s);

s++;

}

}

void ch_send_to_modem(char *s)

{

while(*s != '\0')

{

send(*s);

s++;

}

send('\r');

send('\n');

}

void send(char x)

{

SBUF = x;

while(TI == 0);

TI = 0;

}

void enter()


{

send('\r');

send('\n');

}

COMMUNACATION DETAILS

sms based patient report from remote place1

Documents