Radar based Healthcare

Sensitive radar sensors can detect vital signs such as heart rate and breathing frequency by sensing chest and heart movement. When used in hospitals, care facilities and at home, this can quickly alert care professionals in case of emergency.

This project helped turn a prototype into a production model. A Linux system running on ARM processors turned raw radar sensor data into actionable events, and connected to external networks to store these events in external systems.

Developed by a research lab, the radar sensor was a self-contained unit. It required bulky interface electronics to convert the output to a USB connection with supporting software that was developed to run on powerful desktop computers. It also needed to connect to a small (and cheap) embedded system. The original software only provided raw radar output, which needed to be converted into real-world signals, such as heart rate, or the physical movement of patients.

To connect the sensor to the embedded system, Etosis designed interface electronics that handled power supply, signal conversions, and external connections using a 3G mobile network.

Etosis rewrote the parts of the ARM assembler that targeted the embedded co-processors, optimising the existing radar sensor software and allowing it to run in real time on an ARM processor. To deal with data loss caused by the high data rate of the radar data, Etosis developed a specialised Linux driver for the radar sensor.

Although the electronics used a fairly standard high-speed USB component to communicate, it caused problems in the system because radar sensors produce data in small bursts of large amounts of data. These bursts overloaded the buffers in the driver, which caused data to be lost. A custom USB driver and user-mode software ensured the data was delivered correctly.