Design and Implementation of Digital Blood Pressure Meter

PRESENTATION ON Design and implementation of Digital Blood Pressure Meter

INTRODUCTION:

This application note describes a Digital Blood Pressure Meter concept which uses an integrated pressure sensor, analog signal-conditioning circuitry and microcontroller hardware/software and a liquid crystal display. The sensing system reads the cuff pressure (CP) and extracts the pulses for analysis and determination of systolic and diastolic pressure. This design uses a 50 kPa integrated pressure sensor (Freescale Semiconductor, Inc .P/N: MPXV5050GP) yielding a pressure range of 0 mm Hg to 300 mm Hg.

OBJECTIVE: We have worked to achieve the following goal:

1. To minimize the cost.
2. To maintain the better performance.
3. Easy measuring system.
4. Display with digital unit.

Circuit Diagram

The cuff pressure is sensed by integrated pressure X-ducer. The output of the sensor is split into two paths for two different purposes. One is used as the cuff Since MPXV5050GP is signal-conditioned by its internal op-amp, pressure while the other is further processed by a circuit. The cuff pressure can be directly interfaced with an analog-to-digital (A/D) converter for digitization. The other path will filter and amplify the raw CP signal to extract an amplified version of the CP oscillations, which are caused by the expansion of the subject’s arm each time pressure in the arm increases during cardiac systole. The output of the sensor consists of two signals; the oscillation signal (≈ 1 Hz) riding on the CP signal ( ≤ 0.04 Hz). Hence, a 2-pole high pass filter is designed to block the CP signal before the amplification of the oscillation signal. If the CP signal is not properly attenuated, the baseline of the oscillation will not be constant and the amplitude of each oscillation will not have the same reference for comparison.

CP Signal at the output of the pressure sensor

Extracted Oscillation Signal at the Output of amplifier

Zoom-in View of a Pulse

Output versus Pressure

Comparison between our blood Pressure meter and Omron digital blood pressure meter

Cost Analysis

Parts name	Quantity	Price(TK)
R0,R1,R2,R3,R4,R5,R6,R7,R8,R9,R10	10	30
C1,C2,C3,C4,C5,C6,C7,C8	8	60
LED	1	1
BUZZER	1	30
Crystal Oscillator	1	10
MPXV5050GP	1	1500
LM324N	1	20
MC78L05ACP	1	25
MC34064	1	20
ATmega16	1	180
LCD Display	1	250
Wire	-	10
Cuff	1	70
Total		2206

METHODOLOGY:

1. Theoretical study and analysis of pressure sensor and microcontroller.
2. Calibrate the sensor in corresponding of pressure.
3. Programming the microcontroller.
4. Showing the systolic and diastolic pressure in LCD display.

Future Improvement
Our Digital Blood Pressure Meter can be further improved by-
-Software programming
-Pressure sensor

CONCLUSION: This circuit design concept may be used to evaluate pressure sensors used in the digital blood pressure meter. This basic circuit may be easily modified to provide suitable output signal level. The software may also be easily modified to provide better analysis of the SBP and DBP of a person and also to calculate the pulse rate.

REFERENCE:
[1] Electronic Principles, by Albert Paul Malvino p.h.d,EE,6^th edition,pp 855-898.
[2] www.lvr.com,The Microcontroller Ideal Book, by Jan Axelson,pp 1-10.
[3] www.atmel.com. ATmega 16,data sheet.
[4] IC Design project, by Stephen kamaichick, first edition.
[5] www.alldatasheet.com. MPXV5050GP,data sheet.
[6] www.alldatasheet.com. LM324N,data sheet.
[7] www.mickrobasic.com
[8] www.alldatasheet.com,16×2 Display,Datasheet.
[9] www.fastavr.com
Submitted by Md. Omor Faruk Sharker and Abdul Halim Khan

DESIGN AND FABRICATION OF A HYBRID SOLAR VEHICLE AND A STUDY ON THE CAPABILITY OF IMPLEMENTING SOLAR TECHNOLOGY TO OTHER VEHCLES IN BANGLADESH

Presentation on DESIGN AND FABRICATION OF A HYBRID SOLAR VEHICLE AND A STUDY ON THE CAPABILITY OF IMPLEMENTING SOLAR TECHNOLOGY TO OTHER VEHCLES IN BANGLADESH

Objectives

1. To Design & fabrication of a solar hybrid vehicle.
2. To study the capability of implementing solar technology to the present transportation system of Bangladesh.

Introduction

A solar vehicle is an electric vehicle powered by solar energy obtained from solar panels on the surface of the vehicle. Photovoltaic cells convert the Sun's energy directly into electric energy. Solar vehicles are not practical day-to-day transportation devices at present, but are primarily demonstration vehicles and engineering exercises, often sponsored by government agencies.

 

Methodology

Circuit diagram

Factors to be considered

1. The power need to run the vehicle
2. The area of the solar panel
3. The cost of the solar panel
4. The capacity of the battery to store charge
5. The design and weight of the vehicle
6. Alternate way to run the vehicle in cloudy weather or else.

Data collection and analysis

Comments
Due to high price of solar panel we made a demo vehicle of solar technology to show the mechanism of the system. We used supply voltage from 18v solar panel of EEE department.
Study on the implementation
From various solar panel model we can calculate the area needed to meet the required power.
Model: BP-350 839 x 537 x 50 mm 12 V 50 W
Area=839*537*10^-6m²=0.450543m²
Array power=50/0.450543=110.98 watt/m²
Array voltage=12/0.450543=26.6345 v/m²

Model: BP-380 1209 x 537 x 50 mm 12 V 80 W
Area=1209*537*10^-6m²=0.649233m²
Array power=80/0.649233=123.22 watt/m²
Array voltage=12/0.649233=18.5 v/m²

Calculation for required power
For 2 seats solar electric vehicle power required to run is 746 watt. From BP-380 array power required is 123.22 watts/ m². Therefore area of the solar panel=746/123.22 =6.05 m²
For 4 seats solar electric vehicle power required to run is 2.984kw. From BP-380 array power required is 123.22 watts/ m². Therefore area of the solar panel=2984/123.22 =24.22 m²
Capability of implementation
For buses, trucks, minibuses and other small vehicles we made a survey to implement. We found that the cost of solar panel is absolutely high with increasing the load capacity of the vehicles.

Comparison of cost for different fuels

Solar vehicle economy
A critical study on the revenue of solar technology shows us the way to implement an investment for 20-25 years. It shows that if we invest a large amount at the beginning of the project we can earn 3-4 times profit than other fuels.

Calculation of economy
For 24-26 solar bus:
Initial investment:

Cost of solar panel	=	67,00,000 tk
Cost of solar panel	=	67,00,000 tk
Cost of battery	=	15*7500
	=	1,12,500 tk
Cost of motor	=	3,50,000 tk
Cost of engine	=	8,10,000 tk
Additional investment	=	Cost of solar panel-cost of engine + cost of motor+ cost of battery
	=	6700000-810000+350000+112500
	=	6352500 tk
Interest	=	6%
Depreciation rate	=	A/S
	=	i/(1+i)n
	=	-1
	=	0.0431
Fixed charge rate	=	interest+ depreciation+ insurance premises
	=	6%+4.31%+0.2%
	=	10.51%
Total annual operating cost	=	6352500*10.51%
	=	667600 tk
Operating taxes	=	1% of total annual operating cost
	=	667600*1%
	=	6700 tk
Total annual cost	=	total annual operating cost + annual operating taxes
	=	(667600 + 6700) tk
	=	674300 tk
Lifetime of solar panel	=	25 years
Total cost for running 25 years	=	25*674300
	=	16858000 tk

For 24-26 diesel bus:

Fuel cost	=	11 tk/ km
Average coverage distance	=	500 km/day
Fuel cost	=	5500 tk/day
Total annual cost	=	5500*365
	=	200800 tk
Total cost for running 25 years	=	50200000 tk

Therefore savings for running 25 years=50200000-16858000=33342000 tk.
We see from the calculation that a huge amount of money can be saved by using solar energy.
Conclusion and further study

1. Vehicle should be as light as possible
2. Attached the axle in chassis as straight so that vehicle can move as straight as possible.
3. Select such type of wheel that allow the vehicle minimum friction
4. Efficient rechargeable battery that can store solar energy for long time.
5. Voltage regulation circuit to safe the battery from high voltage supply.
6. Appropriate motor that gives maximum power.
7. Solar energy station.

Submitted by Rokebul Islam Chowdhury and Md.Saiful Islam Swapan

A REMOTE CONTROL SYSTEM FOR HOME AND OFFICE APPLIANCE USING CELL PHONE

Presentation on A REMOTE CONTROL SYSTEM FOR HOME AND OFFICE APPLIANCE USING CELL PHONE

INTRODUCTION:

Devices connected as home and office appliances should be controlled as well as turn on /off if required Most of the times it was done manually. Now a day it is a necessity to control devices more effectively efficiently at any time from any where.

In this project I am going to develop a cellular phone based home/office appliance controller. To active the cellular phone unit on the system a call is to be made and as the call is answered, in response the user would enter a two/three digit password to access the system to control devices.

OBJECTIVES:

1. To develop a system so that it can be controlled by wireless devices and in turn it controls the home appliances connected to it.
2. Develop a system capable of remote access, and saving power by proper controlling devices.

Home and office appliances control by the system

Figure1: Devices connected as home &office appliance controlled by the system

Functional requirements:

The following is a list of functional requirements of the control unit/module.

1. The control unit will have the ability to connect to the cellular network automatically. The control unit will be able to receive DTMF and will be able to for password identification and instructions to be sent to the microcontroller.
2. The microcontroller within the control unit will issue its command to the electrical appliances through a simple control circuit.
3. The control unit will control the electrical appliances and detect the status of the appliances to be relay back to the microcontroller.
4. The system should provide user authentication through cell phone number identification and/or password verification contained within DTMF.

FUNCTIONAL BLOCK DIAGRAM:

Figure 2: Functional block diagram of the system.

METHODOLOGY FLOW CHART

Figure 2: Methodology flowchart

DTMF DECODING BY MT-8870

The MT8870D monolithic DTMF receiver offers small size, low power consumption and high performance. Its architecture consists of a band split filter section, which separates the high and low group tones, followed by a digital counting section which verifies the frequency and duration of the received tones before passing the corresponding code to the output bus.

DECODING OF DTMF BY MT-8870

Figure 3: DTMF Decoding by a dedicated DECODER IC MT-8870

Microcontroller issues command to control devices

After proper decoding of DTMF the decoded output then sent to PIC16F84A microcontroller. Microcontroller issues command to turn on/off devices connected as home and office appliance in accordance with program loaded in it. Then it executes program and provide output RB0,RB!,RB2,RB3.etc output.

Controlling of Devices:

LIMITATION:

1. The receiver must reside in a location where a signal with sufficient strength can be received from a cellular phone network.
2. Only devices with electrical controlling input ports will be possible targets for control.
3. The receiver must have a power source (12V) attached at all times.
4. Operation of the controlling unit is only possible through a cell phone with DTMF capabilities.
5. The controlling unit must be able to receive and decode DTMF.

FUTURE DIRECTION:

1. Possibility of confirming the devices initial condition (status) using short messaging system (SMS).
2. Though mobile in the control panel required to be charged, therefore charging system should be automated which meant a timer can be implemented so that mobile can be charged after a certain period and disconnected from the charger when not required.
3. The possibility to control the devices by voice message.

Submitted by H. M. G. SAROWER

Design & Implementation of an Automatic Fire Extinguishing System

Presentation on Design & Implementation of an Automatic Fire Extinguishing System

Introduction

Fire is the result of a chemical combustion reaction, typically a reaction between oxygen in the atmosphere and some sort of fuel. For the combustion reaction to take place, the fuel has to be heated to its ignition temperature.

Fire extinguishers are designed to remove at least one of these elements thus fire will die out. A fire extinguisher is absolute necessary equipment in any home or office. While there's a good chance that the extinguisher will sit on the wall for years, collecting dust, it could end up saving our property and even our life.

Objectives

1. Provide an automatic fire-extinguishing system which eliminates the disadvantages of the conventional complicated system
2. To enable easy installation or removal of the system in or from a region wherein automatic fire-extinguishing should be effected and
3. To allow a flexible arrangement of gas jetting nozzles according to the size and shape of the region.

Possible Outcome

The microcontroller based adjustable fire extinguishing system has been introduced. Experimental results showed that it provides-

1. Reliability
2. Applicable to different sizes of fire extinguisher
3. High controlling capability over them
4. It allows minimum of maintenance work
5. There is a greatly reduced of malfunction
6. The price-performance relationship is cost effective.

Experimental Design

Experimental Design

1. One fire-extinguisher placed at a desired location containing a fire-extinguishing gas under pressure and a gas jetting nozzle connected through a valve to bomb;
2. One fire sensor arranged at a desired location within said region;
3. An intermediate electric power supply source connected to automatic fire-extinguishing system being provided with a relay to receive an actuation signal from outside
4. And an electro-mechanical means for opening said valve, a gas jetting detecting switch for detecting gas pressure in bomb and a unit control circuit for controlling the actuation of fire-extinguisher

The main part of our project is the involvement of a microcontroller which is the Nucleus of the whole system. We use here PIC 16F84A microcontroller.

Signal conditioning:

The signal conditioning circuit is comprised with a led , transistor and a 741 operational amplifier. The output of the temperature sensor is low; it amplifies the output into a larger voltage signal.

The voltage is further reduced by a resistance to make it a measurable quantity for the comparator circuit. The output voltage is increased by amplifier as microcontroller sense the signal.

Programming:

The assembly language programming is shown below:

MAIN PROGRAM

main

Set up the Ports

TRISA = 255

TRISB = 0

Dim a as Byte

Wait ms 2000

main:

a = PORTA

If a > 0 Then

Wait ms 1000

a = PORTA

If a > 0 then go to alarm

End if

Go to main

alarm:

PORTB = 3

end

Interfacing is the final and most important part of the project. As there are various types of circuits introduced throughout the project it is also important to interface each circuit very carefully as each one has its own purpose.

A regulated power supply circuit which provides 5V dc for the circuit. Next the signal conditioning circuit connected with the solenoid valve is shown. Whenever there is a temperature variation, there is an output pulse results from the comparator circuit. This output is coupled to the microcontroller thereby send a signal to the Buzzer and relay. When relay operates, the solenoid valve is energized and then it is turned on.

References:

1. Operational Amplifiers and Linear Integrated circuits --- Robert F.Coughlin
2. “Microcontroller Technology: 16F84A”, prentice hall -2002.
3. Modern transducer interfacing handbook ----Daniel Sheingold
4. Fire protection ---Harris Corporation.

Submitted By Subir Das and Papan Dey