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SHAJALAL UNIVERSITY OF SCIENCE & TECHNOLOGY,SYLHET:

DEPARTMENT OF INDUSTRIAL & PRODUCTION ENGINEERING PRESENTATION By:Mr . Rakesh kumar sah SHAJALAL UNIVERSITY OF SCIENCE & TECHNOLOGY,SYLHET

OBJECTIVE:

To produce Blood pressure& Glucose meter. To show blood pressure &glucose level in one monitor. To reduce the cost. To give information about further modification. OBJECTIVE

ABSTRACT: :

This paper consists of simple and modified design of blood pressure & glucose meter. These two processes consists of different processes. Blood pressure monitor use oscillometric principal and glucose meter use the mechanism that is used to convert the glucose concentration into a voltage or current signal. The device is composed of a pressure transducer, auxiliary instrumentation for signal acquirement and digital signal processing module in the Lab view environment, transimpedance amplifier etc. ABSTRACT :

KEYSWORDS: :

blood pressure, oscillometry, virtual instrument, glucose, amperometry. KEYSWORDS :

INTRODUCTION :

Our design consists of two devices. One is digital blood pressure monitor and another one is digital glucose meter. We want assemble them together so that they can show both blood pressure level & glucose level in blood in one monitor. The device is consisted of three main parts: external hardwires (such as cuff, motor, valve, and LCD), analog circuit, and microcontroller. The anolog circuit converts the pressure value inside the cuff into readable and usable analog waveforms. The MCU samples the waveforms and performs A/D conversion so that further calculations can be made. In addition, the MCU also controls the operation of the devices such as the button and LCD display. INTRODUCTION

THE REASON OF SELECTING THE PROJECT: :

Today many people suffering from Chronic diabetes and high blood pressure. For that the demand of diabetes and blood pressure measuring machine increases at a very high rate. At first the measuring device was analogue for blood pressure. That time it was mercury sphygmomanometer. Mercury is harmful for environment. For that the need of digital blood pressure monitor increases everyday. It is also faster and accurate. The reason is also same for glucose meter. But today demands for both machine increases for a person. For that reason we have decided to make such an instrument which can show both diabetes and blood sugar readings. THE REASON OF SELECTING THE PROJECT :

Dabetes Fundamentals Diabetes mellitus commonly known as “ diabetes ” is a common health problem throughout the world. It prevents the body from producing enough insulin, does not produce insulin, produces defective insulin, or has resistance to the same. Insulin is a hormone produced in the pancreas.:

Figure . Blood glucose monitor Dabetes Fundamentals Diabetes mellitus commonly known as “ diabetes ” is a common health problem throughout the world. It prevents the body from producing enough insulin, does not produce insulin, produces defective insulin, or has resistance to the same. Insulin is a hormone produced in the pancreas .

DESCRIPTION OF THE PARTS: :

This machine consists of various types parts. Such as : Glucose Sensors. Amperometry. Transimpedance Amplifier. This are for glucose measuring. And for blood pressure measuring we have to use: Pressure Sensor. Motor and Valve Control. DESCRIPTION OF THE PARTS :

Glucose Sensors::

The first step to measure the glucose in the blood is to convert the glucose concentration into a voltage or current signal, this is possible with special sensor strips for amperometry. The sensor uses a platinum and silver electrode to form part of an electric circuit where hydrogen peroxide is electrolyzed. The hydrogen peroxide is produced as a result of the oxidation of glucose ona glucose oxide membrane. The current through the circuit provides a measurement of the concentration of hydrogen peroxide,giving the glucose concentration. Glucose Sensors :

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AMPEROMETRY : Amperometry measures electric current between a pair of electrodes that are driving the electrolysis reaction. Oxygen diffusesthrough the membrane and a voltage is applied to the Pt electrode reducing O2 to H2. These reactive electrodes are amperometric type sensors that use a three electrode design. This approach is useful when usingamperometric sensors due to the reliability of measuring voltage and current in the same chemical reaction.

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Figure .Test strip basic block diagram. Transimpedance Amplifier The transimpedance amplifier consists of an operational amplifier and a feedback resistor between the output and the negative input. The positive input can be connected to either GND or used for offset calibration.

PRESSURE SENSOR: :

This application implements the motor control mentioned in the Figure driven by a pulse width modulation (PWM). The principal device for this application is the MPXV5050GP pressure sensor. This is because it depends on the pressure detected by the MCU so that the motor either turns on or turns off. Also important is an air compressor controlled by the motor and valve.The pressure sensor provides a signal that splits in two. One without a filter, and the other with a filter that removeS noise. MPXV5050GP medical features: • Patented silicon shear stress strain gauge. • Pressure range up to 300 mm Hg (consult the datasheet). • Polysulfone case material (medical, class V approved). PRESSURE SENSOR :

MOTOR AND VALVE CONTROL: :

After the pressure reaches the maximal value of 180 mm Hg the program starts to stabilize the system. It establishes a shorter duty cycle for motor control and a longer duty cycle for valve control and starts to measure the blood pressure. MOTOR AND VALVE CONTROL : Figure . Motor, mini air pump, valve.

DESCRIPTION OF WORKING PRINCIPLE:

1. Hardware diagram: The diagram above shows how our device is operated. The user will use buttons to control the operations of the whole system. The MCU is the main component that controls all the operations such as motor and valve control, A/D conversion, and calculation, until the measurement is completed. The results then are output through and LCD screen for the user to see. DESCRIPTION OF WORKING PRINCIPLE

2.Analogue Circuit::

The analog circuit is used to amplify both the DC and AC components of the output signal of pressure transducer so that we can use the MCU to process the signal and obtain useful information about the health of the user. The pressure transducer produces the output voltage proportional to the applied differential input pressure. The output voltage of the pressure transducer ranges from 0 to 40 mV. But for our application, we want to pump the arm cuff to only 160 mmHg (approximately 21.33 kPa ). 2. Analogue Circuit:

3.Hardware Design: :

Pressure Transducer : We use the MPX2050 pressure transducer from Motorola to sense the pressure from the arm cuff. The pressure transducer produces the output voltage proportional to the applied differential input pressure. We connect the tube from the cuff to one of the inputs and we leave another input open. By this way, the output voltage will be proportional to the difference between the pressure in the cuff and the air pressure in the room. The transfer characteristic is shown in figure 3. Hardware Design :

DC Amplifier: :

Since the output voltage of the pressure transducer is very small, we have to amplify the signal for further processing. We use the instrumentation amplifier AD620 from Analog Devices. The resistor R G is used to determine the gain of the amplifier according to the equation : . DC Amplifier : Fig: Schematic of DC amplifier.

Band pass filter::

The band-pass filter stage is designed as a cascade of the two active band-pass filters. The reason for using two stages is that the overall band-pass stage would provide a large gain and the frequency response of the filter will have sharper cut off than using only single stage. This method will improve the signal to noise ratio of the output. The schematics for both filters are shown in figure . Fig: Band pass Filter Stage Band pass filter:

4.Software Design :

The block diagram for the operating control is consisted of a total of 7 states. We first start at the START state where the program waits for the user to push the white button of the device. Once the white button has been pushed, the measurement process begins by inflating the hand cuff. While the cuff is being inflated, if the user feels very uncomfortable or painful, he/she can push the grey button(emergency button) to stop the motor, quickly deflate the cuff and stop the measurement. 4. Software Design

Design for metrics: :

Fig: State Diagram for Measurement . Design for metrics:

Systolic pressure measurement :

After the motor pumps the pressure up to 160 mmHg which is approximately more than the systolic pressure of normal healthy people, the cuff starts deflating and the program enters Sys_Measure state. In this state, the program will looks at the AC waveform from ADC0 pin. When the pressure in the cuff decreases to a certain value, the blood begins to flow through the arm. At this time if we look at the oscilloscope, we will see the onset of the oscillation. The systolic pressure can be obtained at this point. Systolic pressure measurement

Pulse rate measurement :

After the program finished calculating the systolic pressure, then it starts monitoring the pulse rate of the patient. We choose to determine the pulse rate right after determining the systolic pressure because at this point the oscillation of the waveform is strongest. After the heart rate is determined, the program then enters the Diastolic measure state, in which it tries to measure the diastolic pressure of the patient. Pulse rate measurement

Diastolic measurement :

After the pulse rate is determined, the program enters the Diastolic Measure state. In this state, the program is still sampling the signal at every 40 millisecond. We then define the threshold for the diastolic pressure. While the cuff is deflating, at some point before the pressure reaches diastolic pressure, the amplitude of the oscillation will decrease. To determine the diastolic pressure, we record the DC value at the point when the amplitude of the oscillation decreases to below the threshold voltage. Diastolic measurement

Duration of measurement:            From the start until all the measurements are done, it takes about 1.5 minutes. However, this also depends on each individual and how the cuff is worn. For each person, the amplitude of the waveforms may differ causing the operating time to vary. Still, the difference is small and is usually within 10 seconds. And for glucose measuring it takes 30 sec. :

Accuracy : As mentioned earlier, all the measurements are mainly dependent on the waveforms from the circuit and the pressure sensor is very sensitive to even a slight movement of the user. As a result, it is possible that sometimes the device fails to obtain the desired data, especially if the user does not stay still or wear the cuff improperly. Duration of measurement : From the start until all the measurements are done, it takes about 1.5 minutes. However, this also depends on each individual and how the cuff is worn. For each person, the amplitude of the waveforms may differ causing the operating time to vary. Still, the difference is small and is usually within 10 seconds. And for glucose measuring it takes 30 sec.

Some Components used in this Divice::

Fig. Evaluation board Fig: External equipment. Fig:Test strip Fig: Using the strip. Some Components used in this Divice:

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Fig: Start glucometer Fig: Glucose level. Fig: Connect blood pressure monitor Fig: Start blood pressure monitor Fig: Systolic and diastolic pressure Fig: Heart beats per minutes

COST: :

Cost of some blood pressure and glucose meter is given below: Welch Allyn Vital Signs -$1796.Monitor 300 series Mini Manual Inflate Blood Pressure Monitor Medium -$28.99 But our total machine will cost -$35.00. COST :

FURTHER MODIFICATION: :

For further modification we can combine blood pressure monitor with metabolic glucose meter. Which is called the met a bolic he a t conform a tion (MHC) method, for the non in v a sive me a surement of blood glucose. The MHC method in volves the me a surement of physiologic in dices rel a ted to met a bolic he a t gener a tion a nd loc a l oxygen supply, which correspond to the glucose concentr a tion in the loc a l blood supply. From this it measures glucose. It will reduce unusual cost of strips. FURTHER MODIFICATION :

USES: :

This multipurpose machine is portable. For that people can carry it easily. In today’s market we would find separate blood pressure and glucose meter. But it is suitable for people who are suffering from both disease. It is also suitable for doctors. It also useful in hospitals and clinics. USES :

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