An Efficient Method of Fetching Sensor Values Using Shared Memory

To monitor a car in racing competitions, we have developed a system that consists of sensor nodes, a server, and applications. Because the sensor nodes work on batteries, low power consumption was an important design consideration. We needed to acquire sensor values but also be able to run the system for a long time. Our proposed method that efficiently acquires sensor values from the sensors. In the conventional device driver general-purpose input/output (GPIO) method, processes in the sensor nodes invoke system calls to access the sensors requires significant system overhead. In our proposed method, the processes and device drivers share the same memory. Using our method, device drivers periodically store sensor values in shared memory, while processes fetch sensor values by accessing memory. Because memory access is used instead of system calls, fetching the sensor values requires only low overhead and low power consumption. Experimental results have confirmed that our method reduces processing time for fetching sensor values by 35% when compared with the conventional GPIO driver method.