NIMBuS
The project aims at developing a low cost portable device to measure Blood Glucose level noninvasively, employing Near Infrared spectroscopy technique
FOREWORD
Diabetes mellitus, or diabetes, ranks 7th among the leading causes of death in the world with about 42.2 crore people suffering. Regular monitoring of blood glucose plays a vital role in the control of diabetes. The methods widely used for the administration of blood glucose involves the process of pricking a finger to collect a blood sample. This invasive method induces pain and discomfort in users, increases the risk of the spreading of diseases and is quite costly over the long run. An alternative technology - Continuous Glucose Monitoring has been widely recognized for its convenience and almost pain-free solution for tracking Blood Glucose levels. However, there have been reports of skin rashes and discomfort caused due to usage of the CGM sensor, and it's high cost and short usage duration, reduces the accessibility of this technology.
On basis of these factors and after a thorough literature survey, a method was devised to estimate the blood glucose data using Near-Infrared (NIR) Spectroscopy in a non-invasive manner. This method involves acquiring the signal and processing it through appropriate amplification and filtering and storing the relevant data. An AI based algorithm will be subsequently implemented to calibrate the device uniquely to match the user's physiological parameter and to other environmental factors such as Temperature, Humidity, Motion Artifacts, etc.
During the calibration and testing phase of the project the Self Blood Glucose Monitoring (SBGM) kit was used as a reference.
METHOD
The project aims at using NIR spectroscopy to perform fingertip photoplethysmography (PPG). Plethysmography is a technique of measuring the blood volume changes in any part of the body that result from the pulsation of the heart. These measurements are useful in the diagnosis of arterial obstructions and pulse wave velocity measurements. Photoplethysmography is the simple and low-cost optoelectronic method for measuring the blood volume changes in the microvascular bed of the tissue. It is often used noninvasively to make the measurements at the surface of the skin.
The IR absorbance spectroscopy obeys the Beer-Lambert Law, which states that “the quantity of light absorbed by the substance dissolved in a fully transmitting solvent is directly proportional to the concentration of the substance and the path length of the light through the solution.” Hence, as the concentration of the medium through which the IR radiation is passed increases, the absorption of the radiation by the corresponding molecules increases and the intensity of the transmitted radiation decreases.
The Block Diagram represents the flow of signals/data in the system. The output from analog sensor is first passed through the passive high pass filter. The amplification of the signal and conversion from a current signal to a voltage signal takes place at the transimpedance amplifier. Further noise elimination takes place at the 4th order Butterworth Low Pass Filter. The Butterworth filter is chosen to obtain a ripple-free pass-band and stop-band. This gives a cleaner and more accurate output signal.
The filtered analog signal is passed through the ADC to convert it into a digital signal. The digital signal is sampled at a frequency of 10–15Hz. The obtained signal data are further filtered using a digital high pass filter to remove low frequency noise. FFT is performed on this data and data analysis is performed on the data in frequency domain.
FUTURE SCOPE
A highly accurate, consistent Non invasive Blood Glucose Measurement device has still not been developed due the physiological differences within subjects over the long-term, as well as the physiological differences between subjects.
As mentioned previously, the accuracy of such devices is affected not only by physiological and demographical parameters but also due to the working environment. Further, the effect of such factors can be studied through extensive testing, both in vivo and in vitro, and necessary hardware solutions can be developed to annul those effects.
The design could be further improved through advanced techniques such as Automatic Gain Control, Motion Artifact filtering, Temperature Compensation and Multi-Channel Sensor
approach to improve accuracy.
THESE WERE SOME MAJOR LEARNINGS OR POINTS I WANTED TO CALL OUT
Skills Learnt/Improved
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Embedded System Design
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DSP (FFT) using C++
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Analog Circuit Design
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MATLAB
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LaTeX
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Research Paper
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Leadership Skills
Meet the Team
Tejas S Shah
Divya P Pathak
Special Thanks To
P Kavya Shree
D S P Kashyap
Publication Details
Research Paper Title: Noninvasive Measurement of Blood Sugar using NIR Sprectroscopy
Book Chapter Publisher: Scrivener Publishing by WILEY
Presented at International Conference on Innovations in Electronics, Communication, Computing & Automation
Mentors
Guide:
Dr. Chakravarthula Kiran
Associate Professor
Dept. of EIE, VNRVJIET
Co-Guide:
Dr. Poonam Upadhyay
Head of Dept. & Professor
Dept. of EEE, VNRVJIET
Funded By
VNR Vignana Jyothi Institute of Engineering and Technology
