Design and Implementation of an Underwater Telemetric Glucose Monitoring System for Scuba Divers

Abstract

Despite the abundance of telemetric applications for ecology, behaviour and physiology of marine life, few efforts were reported about the use of acoustic telemetry for SCUBA divers. Such systems are required to follow the medical conditions of divers with chronic health problems such as diabetics. This study communicates the details of a study to design, manufacture and test a prototype system that measures the blood glucose while diving and transmit the results in real time to the surface. A subcutaneous glucose sensor placed on the diver transmits wirelessly the glycaemia data to a microcontroller based RF receiver board placed in a custom built waterproof casing. This board works as a relay to transmit the blood glucose value to an acoustic modem SAM-1 Desert Star Systems LLC, Monterey Bay, CA, USA via RS232 serial communication. The modem transmits the data to the other modem, which is placed underwater at 1 m depth with a maximum baud rate of 100 bit/sec with ultrasound communication. Finally, the data reaches a portable computer from RS232 serial interface of the acoustic modem. The data is displayed and logged on the computer based at the surface. The whole system is tested to 11 Bar in hyperbaric chamber. The acoustical data link is first established between two computers located at surface to test the reliability of the communication. The acoustical link experiments were successful for 20 minutes of simulated signals for the depth, interstitial glycaemia, breathing frequency and temperature information. The overall efficiency was 80.1%, with 474 bytes sent and 378 bytes received. The bandwidth of the acoustical link is very low max 4 reading/min but is adequate for glycaemia monitoring that can be as low as 1 reading every 5 minutes. Finally the system recorded the interstitial glucose of divers in 8 open water dives successfully and will be beneficial for studying diabetic divers. The system has a potential to be used to verify and optimize the existing protocols on diabetic divers. It offers as well an emergency system to monitor the non-diabetic divers during extreme exposures such as saturation diving.

Keywords

• Diabetes,Underwater,Diving,Glycaemia,Subsea,Real time monitoring

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