A Low-Power Data Logger With Simple File System for Long-Term Environmental Monitoring in Remote Areas

Abstract

This research addresses the long-term measurement of environmental data in geographically remote areas and an energy-optimized method of storing data on a storage medium. For this purpose, we have developed our measurement module Advanced Data Logger (ADL). In terms of connectivity, the module operates in three modes: 1) offline - when measured data is primarily stored on the storage medium; 2) Internet of Things (IoT) ready - measured data is stored on the storage medium and sent to the remote server in defined batches; and 3) online mode - when measured data is preferably sent to the remote server immediately after measurement. The design aims to minimize the module's power consumption so that the autonomous operating time is close to one year. As part of the design, the Simple File System (simpleFS) software module is designed for the role of a simple file system (FS) optimized to minimize I/O operations. Its other feature in data storage is the automatic normalization of the data transmitted from the attached sensors. The last part of the design is the AdlReader software solution, used to configure the hardware (HW) module and to retrieve the measured data files. We verified the correct operation of the ADL module along with nine sensors built in a vertical soil temperature profile probe in experimental installation and operation for two months. According to the requirements for our solution, the expected operation time of the ADL module is 9-12 months.