Evaluation of power saving methods for low-power WiFi environment sensors
Tomáš Přeučil, Martin Novotný · 2022 11th Mediterranean Conference on Embedded Computing (MECO) · 2022
Environment sensing devices are all around us and the instruction cycle of these devices is usually simple: wake up, measure data, send them to a central unit or to the cloud and enter deep sleep. These devices also need to last as long as possible on a single charge and when we say single charge, we mean months at least. This leads to one common problem-these devices usually use low data rate networks like ZigBee or LoRa and therefore are not easy to deploy for a common user. There are several ways of achieving low power consumption when using WiFi. This paper describes and evaluates these methods and recommends power-saving methods for the WiFi module ESP8266. This paper also describes the development of a reference low-power device that can sense the environment (temperature, humidity and pressure in this case) and uses 2.4 GHz WiFi. Therefore, this device does not need any sort of gateway and can connect directly to the network most users already have deployed. Current programming allows for quick and easy transmission of the data to an MQTT server. It is easy to quicks tart usage and mass production of the presented prototype. The system is based on the popular ESP8266 as a base for measurement, processing and WiFi communication. For power management, more circuitry is used. The paper presents a full reference schematics of the developed device.