Multi-sensor system for remote environmental (air and water) quality monitoring

In this paper realization of the low-power, portable, low-cost multi-sensor system for air and water quality monitoring is described. Developed system is battery-powered with solar panel-based charger unit, and it is intended for use in remote environmental monitoring by collecting information about air temperature (T) and relative humidity (RH), presence of volatile organic compounds (VOC) as well as water temperature and pH level. The hardware of the system is based on the ATmega128 microcontroller which acquires the sensors data and coordinates the work of all peripherals. To establish full standalone operation, peripherals such a TFT color LCD display, embedded keypad and SD card for data storage are included. Air quality parameters are collected with SHT11 (T and RH) and MQ-135 (VOC) sensors, while water temperature is monitored with encapsulated LM35 sensor. For pH level monitoring, TiO
₂
-based thick film pH resistive sensor was fabricated and characterized. The pH sensor readout electronics, based on the integrated circuit AD5933, is designed in such way to ensure reliable in-situ measurements. Discussion of the applications of the proposed system in the more complex, a cloud-based, system for air and water quality monitoring in real-time, with the IBM Watson IoT platform is given as well.