Recommended · for some experience
#58 ESP8266 Sensor runs 17 days on a coin cell/transmits data (deep-sleep)
Why people recommend it
Andreas Spiess builds an ESP8266 sensor that runs 17 days on a coin cell using deep sleep; a common starting point for battery-powered Wi-Fi sensor projects.
Watch for: power draw figures from about 11:20
In their words
The module is quite low power, and it may run for some days with AA batteries.
dariosalvi on arduino.stackexchange.com, Aug 2016. CC BY-SA.
