Non-Invasive Blood Glucose Measurement Using Near-Infrared Spectroscopy and Microcontroller Equipment

This study focuses on the development of modern, non-invasive equipment for measuring blood glucose levels using near-infrared (NIR) spectroscopy with a transmitter of 940 nm wavelength light emitting diode (LED). The aim is to eliminate the need for invasive methods and provide greater convenience for patients. The equipment operates by emitting infrared spectrum from a high-speed LED VLSB3940, which is passed through the patient's fingertip and receive by a BPX 65 photodiode receiver. The received signal is converted into voltage by the BPX65 photodiode. The output voltage from the BPX65, which varies with glucose concentration in the blood, is then amplified by an operational amplifier (op-amp) circuit. The amplified voltages are collected by an Arduino microcontroller that is interfaced with a touch screen display. A corresponding C-Arduino language program controls all processes and displays the measurement results on the screen. The study concludes that the near-infrared spectrum can effectively transmit signals through the blood glucose in the fingertip, yielding results comparable to the old invasive method. The linear regression of invasive and non-invasive blood glucose measurements had R² values of 0.99 and 0.82, respectively. The plot of Clarke Error Grid Analysis (CEGA) showed that most of points were in zone A, indicating high accuracy. However, further development of the system is recommended, including the exploration of alternative transmitters of 1550 nm wavelength, better receivers, and circuits to optimize the equipment for commercial uses.