BIOMEDICAL MONITORING SYSTEM

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INTRODUCTION

OBJECTIVE

In this project our object is to develop a “Biomedical Monitoring System” that is capable to transmit the patient’s heartbeat collected by microcontroller unit and display it on the LCD.

SCOPE OF PROJECT This project is very useful for continuous monitoring of the patient’s heartbeats this is a very useful product in hospital

BASIC COMPONENTS REQUIRED

Components required in this project are as follows:

1. 8-bit Microcontroller (89c2051).2. Operation Amplifier LM 358.3. Encoder IC HT 12E.4. 16x2 LCD.5. Buzzer.6. Voltage regulator 78XX.7. Resistors, Capacitors, Diode (IN 4007).

A BRIEF INTRODUCTION TO AT89C2051 MICROCONTROLLER: 

When we have to learn about a new computer we have to familiarize about the machine capability we are using, and we can do it by studying the internal hardware design (devices architecture), and also to know about the size, number and the size of the registers.

A microcontroller is a single chip that contains the processor (the CPU), non-volatile memory for the program (ROM or flash), volatile memory for input and output (RAM), a clock and an I/O control unit. Also called a "computer on a chip," billions of microcontroller units (MCUs) are embedded each year in a myriad of products from toys to appliances to automobiles. For example, a single vehicle can use 70 or more microcontrollers. The following picture describes a general block diagram of microcontroller.

89C2051:

The AT89C2051 is a low-voltage, high-performance CMOS 8-bit microcomputer with 2K bytes of Flash programmable and erasable read-only memory (PEROM). The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the AT89C2051 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications. The AT89C2051 provides the following standard features: 2K bytes of Flash, 128 bytes of RAM, 15 I/O lines, two 16-bit timer/counters, a five vector two-level interrupt architecture, a full duplex serial port, a precision analog comparator, on-chip oscillator and clock circuitry. In addition, the AT89C2051 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The power-down mode saves the RAM contents but freezes the oscillator disabling all other chip functions until the next hardware reset.

BLOCK DIAGRAM

OPERATION AMPLIFIER (LM 358)

The LM158 series consists of two independent, high gain, internally frequency compensated operational amplifiers which were designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the power supply voltage.Application areas include transducer amplifiers, dc gain blocks and all the conventional op amp circuits, which now can be more easily implemented in single power supply systems. For example,

the LM158 series can be directly operated off of the standard +5V power supply voltage which is used in digital systems and will easily provide the required interface electronics without requiring the additional ±15V power supplies. The LM358 and LM2904 are available in a chip sized package (8-Bump micro SMD) using National’s micro SMD package technology.

Features

Available in 8-Bump micro SMD chip sized package, Internally frequency compensated for unity gain Large dc voltage gain: 100 dB Wide bandwidth (unity gain): 1 MHz (temperature compensated) Wide power supply range:

— Single supply: 3V to 32V— or dual supplies: ±1.5V to ±16V

Very low supply current drain (500 μA)—essentially independent of supply voltage Low input offset voltage: 2 mV Input common-mode voltage range includes ground Differential input voltage range equal to the power supply voltage Large output voltage swing

Voltage Controlled Oscillator (VCO)

Connection Diagram

LIQUID CRYSTAL DISPLAY (LCD)

A liquid crystal display (LCD) is an electro-optical amplitude modulator realized as a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. It is often utilized in battery-powered electronic devices because it uses very small amounts of electric power.

Each pixel of an LCD typically consists of a layer of molecules aligned between two transparent electrodes, and two polarizing filters, the axes of transmission of which are (in most of the cases) perpendicular to each other. With no liquid crystal between the polarizing filters, light passing through the first filter would be blocked by the second (crossed) polarizer.

The surfaces of the electrodes that are in contact with the liquid crystal material are treated so as to align the liquid crystal molecules in a particular direction. This treatment typically consists of a thin polymer layer that is unidirectional rubbed using, for example, a cloth. The direction of the liquid crystal alignment is then defined by the direction of rubbing. Electrodes are made of a transparent conductor called Indium Tin Oxide (ITO

BUZZER

A buzzer or beeper is a signaling device, usually electronic, typically used in automobiles, household appliances such as a microwave oven, or shows. buzzer is a ceramic-based piezoelectric sounder like a Son alert which makes a high-pitched tone.

POWER SUPPLY

REGULATOR IC (78XX)

It is a three pin IC used as a voltage regulator. It converts unregulated DC current into regulated DC current.

Pin Description of 78xx1. Vin2. GND3. Vout

BRIDGE RECTIFIER

A bridge rectifier makes use of four diodes in a bridge arrangement to achieve full-wave rectification. This is a widely used configuration, both with individual diodes wired as shown and with single component bridges where the diode bridge is wired internally.

CIRCUIT DIAGRAM OF POWER SUPPLY

CIRCUIT DIAGRAM

FUTURE ENHANCEMENT

In spite of the improvement of communication link and despite all progress in advanced communication technologies, There is still very few functioning commercial WirelessMonitoring Systems, which are most off-line, and there are still a number of issues to deal with.Therefore, there is a strong need for investigating the possibility of design and implementation of an interactive real-time wireless communication system. In our project, a generic real-time wireless communication system was designed and developed for short and long term remote patient-monitoring applying wireless protocol. The primary function of this system is to monitor the temperature and Heart Beat of the Patient and the Data collected by the sensors are sent to the Microcontroller. The Microcontroller transmits the data over the air.At the receiving end a receiver is used to receive the data and it is decoded and fed to Microcontroller, which is then displayed over the LCD display. If there is a dangerous change in patient's status an alarm is also sounded.

CONCLUSION

The greatest learning experience in this project comes from the design and construction of “PC Based Appliance Controller” which answer a lot of questions regarding the real implementation of embedded system, Microcontroller, LCD.During the development of our project we studied and analyzed many real world applicationsof Electronics and Software Engineering. Some of the theoretical knowledge that was inculcated in us within our engineering program, which we have applied practically, is:

1. Use of voltage regulation and filtering in power supply.2. Study of LCD.3. Study of Microcontroller.