FPGA BASED DATA ACQUISITION SYSTEM
Prof. Mrs. Vaishali Baste1, Mrs.D.K.Shende2, Mrs. S.K.More3, Amol More4
Dept. of Electronics and Telecommunication, Sinhgad Institute of Technology, Lonavala, India1,2,3,4 [email protected]1, [email protected]2, [email protected]3, [email protected]4
Abstract
This presents a novel approach to the design of data acquisition system for patient monitoring in medical applications. The core heart of the proposed system is Field Programmable Gate Array (FPGA) which is configured and programmed to acquire a real time data. Real time data from the process is acquired using suitable sensors. Signal conditioners are designed for each sensor.
FPGA based data acquisition system along with corresponding signal conditioners is validated in real-time by running the process and comparing the same with the corresponding references
Design mainly involves the development of signal conditioning circuits for the sensors used in the application and programming the FPGA using a hardware description language.
FPGA utilized as a data acquisition system is programmed to send the output signals for channel selection and start of conversion for ADC. The Programming is done to fetch the data at the output of ADC once an end of conversion is received from the ADC. The program will also output the measured values on an LCD display and waveforms will be displayed on PC / Computer
Key Words— FPGA, Electrocardiogram (ECG), Xilinx, FPGA
I. INTRODUCTION
Data acquisition systems, as the name implies, are products and/or processes used to collect information to document or analyze some phenomenon. As technology has progressed, this type of process has been simplified and made more accurate, versatile, and reliable through electronic equipment. Equipment ranges from simple recorders to sophisticated computer systems. Data acquisition products serve as a focal point in a system, tying together a wide variety of products, such as sensors that indicate temperature, flow, level, pulse rate, electrocardiograph etc.
This presents a novel approach to the design of data acquisition system for process applications.
The core heart of the proposed system is Field Programmable Gate Array (FPGA) which is configured and programmed to acquire a real time data. Real time data from the process is acquired using suitable sensors. Signal conditioners are designed for each sensor. Signal conditioners are interfaced with FPGA through ADC and MAX 232 for PC interfacing. Output of the system is displayed on LCD and waveforms on PC.
The patients need to visit clinic often. In today’s fast moving world it is not feasible for the people to visit clinic regularly, also it is difficult for old persons to go to the clinic by their own. In such cases this system can be useful. Suppose you are admitted in hospital for operation purpose. After operating upon you doctor will inform you to be in a hospital for few days. If you observe the activity performed by nurses or
Doctors; you will find that nurse will visit you thrice a day and jot down all the parameters on a note pad. Doctor will visit you once in a day, go through the note pad and will put a remark on it.
After Few days you get discharge from the hospital.
In this system the pulse rate and body temperature of the patient is monitored. Here, this data acquisition system is to develop for patient monitoring in hospitals as well as in homes also.
II. SCOPE OF THE WORK
This Paper is useful in medical applications and offers less cost and size than ECG (Electro Cardiography). In the case of emergency for old people who are suffering with diseases like heart disease continuous monitoring of the patient is required which is sometimes not possible in the hospital, or the patient location is far away from the hospital. In such a case this prototype circuit is useful to measure the pulse rate as well as temperature of the person and the information can be used to the medical advisory for the preliminary precautions so that patient can be under control, prevented from serious situation before reaching to the hospital.
This data acquisition system is to developed for patient monitoring that includes human body temperature, pulse rate measurement and electrocardiograph.
III. SYSTEM COMPONENTS
The project is used to monitor a patient's pulse rate, body temperature and ECG. It
accomplishes this by using pulse rate sensor to measure pulse rate,, the body temperature sensor LM35. Data is digitized with an FPGA microcontroller and sent to a computer and LCD using RS232 serial standard. The implementation of the Project pulse rate , Body Temperature monitor is a success. The Project is portable and runs on less power.
The existing procedure for measuring pulse rate is both erroneous and inadequate; patients alter their pulse rate when they are aware that they are being observed, and nurses can only spare a short time in which to get an accurate measurement. In addition, current hospital technology used to monitor a patient’s heart rate is often large and awkward.
ECG waves displays on PC.
Here we are developing a low cost, low power system. The system improves the quality of patient monitoring and eliminates the need for nurses to repeatedly manually perform these measurements.
Figure 1: Block Diagram of FPGA based Data Acquisition System for Patient Monitoring
FPGA UNIT:
The Spartan-3E family of Field- Programmable Gate Arrays (FPGAs) is specifically designed to meet the needs of high volume, cost- sensitive consumer electronic. The Spartan-3E family builds on the success of the earlier Spartan-3 family by increasing the amount of logic per I/O,
significantly reducing the cost per logic cell. New features improve system performance and reduce the cost of configuration. These Spartan-3E FPGA enhancements, combined with advanced 90 nm process technology, deliver more functionality and bandwidth per dollar than was previously possible, setting new standards in the programmable logic industry. Because of their exceptionally low cost, Spartan-3E FPGAs are ideally suited to a wide range of consumer electronics applications, including broadband access, home networking, display/projection, and digital television equipment.
LIQUID CRYSTAL DISPLAY:
LCD is used in a project to visualize the output of the application. We have used 16x2 LCD which indicates 16 columns and 2 rows. So, we can write 16 characters in each line. So, total 32 characters we can display on 16x2 LCD.
Figure 2: 16*2 Alphanumeric LCD
LCD can also used in a project to check the output of different modules interfaced with the microcontroller. Thus LCD plays a vital role in a project to see the output and to debug the system module wise in case of system failure in order to rectify the problem.
COMPUTER / PC :
Computer / PC is used in a project to visualize the output of the application. Computer /
PC is interfaced for the Electrocardiography. A waveform of ECG can be visualize on Computer / PC.
RS 232:
RS 232 is a serial communication cable used in the system. Here, the RS 232 provides the serial communication between the microcontroller and the outside world such as display, PC or Mobile etc. So it is a media used to communicate between microcontroller and the PC. In our project the RS232 serves the function to transfer the data in between PC
and the FPGA, for the further operation of the system
TEMPERATURE SENSOR:
Temperature sensor is used to sense the temperature. We have used a Temperature sensor LM35. This temperature sensor can sense the temperature of the atmosphere around it or the temperature of any machine to which it is connected or even can give the temperature of the human body.
So, Irrespective of the application to which it is used, it gives the reading of the temperature. The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature
Figure 3: Block of LM35
PULSE RATE SENSOR:
The pulse rate sensor is basically used to keep track on the pulse rate of the person. In programming the maximum and the minimum set point are provided for the pulse rate. If the pulse rate goes below or above the set point then the alert will be immediately issued by the FPGA.
ECG INFORMATION:
ANATOMY AND FUNCTION OF HEART:
The heart serves as a four-chambered pump for the body's blood circulatory system. The four chambers are names as: left atrium, left ventricle, right atrium and right ventricle. The following diagram shows the route of blood circulation (where the red color indicates the oxygen-rich arterial blood while the blue color indicates the oxygen-poor venous blood.
Figure 4: Flow of Blood Circulation
The main pumping function is supplied by the ventricles, and the atria are merely antechambers to store blood during the time the ventricles are pumping. A complete heart cycle is divided into two phases: systole and diastole. Systole refers to the contractile or pumping phase; and diastole refers to the resting or filling phase
The rhythmic contraction of the atria and ventricles has an underlying electrical precursor in the form of a well-coordinated series of electrical events that takes place within the heart. This series of electrical events originates in the Sino Atrial (SA) node which is located at the junction of the superior vena cava and the right atrium. The SA node acts as a pulse generator. Each impulse generated by the SA node leads to a heart-beat. Therefore, in a normal heart, the heart rate (beats per minute) is determined by the period of the pulses generated by the SA node. The impulse generated by the SA node first spreads all over the muscles of the two atria, causing the contraction of the atria. After a short delay, the impulse spreads over the muscles of the two ventricles and cause their contraction. The ECG waveform recorded on the body surface is produced by the electrical activities associated with the muscles contraction and relaxation of the atria and ventricles.
NORMAL ECG WAVEFORM:
Figure 5: Ideal ECG Waveform
P-wave is produced by muscle contraction of atria.
R-wave marks the ending of atrial contraction and the beginning of ventricular contraction.
Finally, T-wave marks the ending of ventricular contraction. The magnitude of the R-wave normally ranges from 0.1 mV to 1.5 mV.
A narrow and high R-wave indicates a physically strong heart.
The R-R interval measures the period of heart beat. Its inverse is the heart rate:
HR= 60000/(R-R) bpm
Where, HR is the heart rate measured in beat- per-minute (bpm), R-R is the R-R interval measured in millisecond (ms). For example, if R-R is 800 ms, the heart rate is 75 bpm. The R-R interval should be relatively constant from beat to beat. A changing R-R interval indicates irregular heart rate.
The P-R interval is a measure of the time from the onset of atrial contraction to the onset of ventricular contraction. It normally ranges from 0.12 to 0.20 second. An abnormally prolonged P-R interval often indicates a special heart disease called "First Degree Heart Block". The R-T interval represents the ventricular systole (muscle contraction) and the T-R interval represents the ventricular diastole (muscle relaxation).
FLOWCHART:
Figure 6: The design is implemented on FPGA board
ADVANTAGES:
• Less time delays
• Quick response time.
• Fully automate system
• Robust system
• Low power requirement
APPLICATIONS:
Medical Application
o Patient Monitoring
Industrial Application
o Small Scale Industry
o In Steam Power Plants
o In Chemical Industry
In Greenhouse
Automation Industry
IV RESULT
ECG RESULT WAVEFORM
Figure 7: ECG Result Waveform
TEMPERATURE AND PULSE RATE RESULT:
Figure 8: Temperature and Pulse Rate result
CONCLUSION:
FPGAs (Field Programmable Gate Arrays) are finding wide acceptance in medical systems for their ability for rapid prototyping of a concept that requires hardware/software co-design, for performing custom processing in parallel at high data rates and be programmed.
REFFERENCES
JOURNAL PAPERS:
[1] Kiran Kumar Jembula et al, “Design Of Electrocardiogram (ECG Or EKG) System On FPGA”, International Journal Of Engineering And Science ,Vol.3, No.2, pp 21-27, May 2013.
[2] Cheng Dong et al, “A Real-Time Heart Beat Detector and Quantitative Investigation Based on FPGA”, International Conference on Microelectronics and Electronics, pp.65-69, Oct.2011.
REFFERENCE BOOKS:
[1] Dogan., I., Kadri., B, 2012, Hear Rate Measurement from the Finger using a low cost Microcontroller.
[2] Pong P. C., 2008, FPGA Prototyping by VHDL Examples: Xilinx Spartan-3 Version, Publisher:Wiley-Interscience
[3] Webster, EDS, 1981, Design of Microcomputer-Base Medical Instrumentation, Prentice Hall International, New Jersey.
[4] Kevin skahill, “ VHDL for programmable logic”,1sted, pearson education, 2006.
WEBSITES:
[1] www.atmel.com
[2] www.nationalsemiconductors.com [3] www.dallassemi.com
[4] www.google.com
