Wireless sensor network for homes in the tropics

Abstract

This report documents the enhancements made to an existing wireless sensor network. The end-devices are to be deployed around a tropical home to collect temperature and relative humidity readings, transmitting to a data-logging coordinator which stores the readings for further analysis. The enhancements are separated into two parts – improving the energy efficiency of the end-devices, and improving the deployment capability of the data-logger. The first part of the project is done in three main aspects – shifting towards a single circuit voltage to reduce energy wastage from signal bridging circuits, minimising number of parts used and hence lowering energy consumption, and adding support for different modes such as a normal mode for normal deployment and debug mode for high resolution data, and different input power supplies such as batteries for end-devices and USB for routers. The second part of the project improves on the software of the Raspberry Pi data-logger in two main aspects – implementing auto-start feature to make the data-logger usable with just a power source instead of originally requiring human involvement to start the program, and installing a battery-powered clock so that data captured is real-time without needing the Internet to synchronise time on each boot-up. The enhancements to the project enable it to be deployment-ready and able to last for up to and over a year of use with a mix of USB and battery power.