The Networked Nitrous Node: A Low-Power Field-Deployable COTS-Based N$_{2}$O Gas Sensor Platform

Abstract

We present a wireless nitrous oxide (N <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{2}$</tex-math></inline-formula> O) gas sensor system consisting of a commercial high-current infrared N <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{2}$</tex-math></inline-formula> O sensor wrapped in a “smart” sensor framework to make it suitable for battery-powered deployment. This framework consists of wireless mesh networking, data storage, additional environmental sensors, and a gas sensor power control circuit managed by a central microcontroller. The N <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{2}$</tex-math></inline-formula> O sensor is the first order consumer of power and sampling N <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{2}$</tex-math></inline-formula> O at approximately ten minute intervals yields an estimated system lifetime of 63 days when using four 18650 Li-ion batteries. The node stores data locally on SD card and wirelessly reports to a root PC that also stores data and displays to users in a simple graphical user interface. The system is composed of majority off-the-shelf components and any custom components were designed or programmed with open-source software. We expect these features will lead to this system being more easily understood, copied, and modified by engineers wishing to design similar sensor system frameworks and thereby allow even more power-prohibitive devices to be wirelessly deployed.