Drone-Mountable Gas Sensing Platform Using Graphene Chemiresistors for Remote In-Field Monitoring

Abstract

We present the design, fabrication, and testing of a drone-mountable gas sensing platform for environmental monitoring applications. An array of graphene-based field-effect transistors in combination with commercial humidity and temperature sensors are used to relay information by wireless communication about the presence of airborne chemicals. We show that the design, based on an ESP32 microcontroller combined with a 32-bit analog-to-digital converter, can be used to achieve an electronic response similar, within a factor of two, to state-of-the-art laboratory monitoring equipment. The sensing platform is then mounted on a drone to conduct field tests, on the ground and in flight. During these tests, we demonstrate a one order of magnitude reduction in environmental noise by reducing contributions from humidity and temperature fluctuations, which are monitored in real-time with a commercial sensor integrated to the sensing platform. The sensing device is controlled by a mobile application and uses LoRaWAN, a low-power, wide-area networking protocol, for real-time data transmission to the cloud, compatible with Internet of Things (IoT) applications.

Ambient Monitoring Portable Sensor Node for Robot-Based Applications

“…Park et al proposed a drone-based gas detection system for remote monitoring [ 24 ]. The gas sensing element is fabricated from a graphene chemiresistor array.…”

Arrays of Functionalized Graphene Chemiresistors for Selective Sensing of Volatile Organic Compounds

“…Among these material platforms, graphene devices are especially promising for the development of light, portable, and low-power gas sensors. Recent work also demonstrated their potential in real-life applications, notably by mounting them on a drone and using a control sensor and algorithm able to significantly reduce noise from fluctuating environmental conditions . In addition to being thin and chemically stable, graphene’s conical band structure around the Fermi level ensures that small changes in the electrostatic environment around a graphene chemiresistor result in significant changes in its resistance. , Consequently, graphene sensors have demonstrated high sensitivity toward gases such as ethanol, dimethyl methylphosphonate (DMMP), NO, NO 2 , and NH 3 . − Selectivity of such devices, however, is a distinct challenge for which researchers have explored UV illumination and chemical functionalization − as new strategies.…”

“…Recent work also demonstrated their potential in real-life applications, notably by mounting them on a drone and using a control sensor and algorithm able to significantly reduce noise from fluctuating environmental conditions. 12 In addition to being thin and chemically stable, graphene's conical band structure around the Fermi level ensures that small changes in the electrostatic environment around a graphene chemiresistor result in significant changes in its resistance. 13,14 Consequently, graphene sensors have demonstrated high sensitivity toward gases such as ethanol, dimethyl methylphosphonate (DMMP), NO, NO 2 , and NH 3 .…”