Optimizing Power Consumption of Wi-Fi inbuild IoT device

The Internet of Things (IoT) – connection of small smart sensors, actuators and other devices to the Internet – is a key concept within the smart home. To ease deployment, such devices are often wireless and battery powered. An important question is the wireless interface used. The ubiquity of WiFi in homes today makes this an attractive option, but the relatively high power requirements of Wi-Fi conflict with the requirement for long battery life and low maintenance. Lower power alternatives, such as Bluetooth and Zigbee, have been proposed, but these have a much smaller installed base. In addition, many Smart Home products are currently available using 433MHz technology. This paper considers whether it is possible to reduce Wi-Fi power usage to the point where cheap Wi-Fi based products can be used instead of other protocols. The paper undertakes power analysis of a wireless sensor with an SoC Wi-Fi module, with and without a separate microcontroller optimised for low power usage which can be used to switch the Wi-Fi module on and off. This paper is an extension of previous work comparing Wi-Fi and 433MHz devices, and so we compare 433MHz to the optimised Wi-Fi sensor. Finally, the paper considers the energy usage of DHCP, demonstrating that further energy savings can be made if the application handles IP addressing and presents a static IP address to the Wi-Fi module.