Smart-Autonomous Wireless Volatile Organic Compounds Sensor Node for Indoor Air Quality Monitoring Application

Area of Science:

• Environmental Science
• Sensor Technology
• Public Health

Background:

• Indoor air quality significantly impacts human health, comfort, and productivity, with volatile organic compounds (VOCs) posing chronic health risks.
• Effective indoor air quality monitoring (IAQM) is crucial due to extensive human exposure within buildings (80%-90% of activity).

Purpose of the Study:

• To develop a wireless sensor node for autonomous indoor air quality monitoring (IAQM) focused on volatile organic compounds (VOCs).
• To implement a low-power strategy for extended autonomous operation of the VOCs sensor node.

Main Methods:

• Utilized an AVR microcontroller (ATmega-4808) and a low-power IAQ-Core sensor for VOC detection.
• Developed a low-power sensing algorithm enabling autonomous operation with a total power consumption of 0.22 mAh per 30-minute cycle.
• Integrated a 10F supercapacitor to power the sensor node for 139 seconds per cycle.

Main Results:

• The sensor node achieved a low power consumption of 0.22 mAh per cycle, with data transmission being the highest power consumer (58%).
• A 1541-minute field experiment successfully measured and displayed real-time total volatile organic compounds (TVOCs) and CO2 values online.
• Recorded TVOCs levels of 175 ppb, indicating good indoor air quality.

Conclusions:

• The developed wireless VOCs sensor node provides an effective solution for autonomous IAQM with a low-power strategy.
• Further research into micro energy harvesting is recommended to enhance the sensor node's operational lifetime.
• The system successfully demonstrated real-time monitoring of indoor air quality parameters like TVOCs and CO2.