Weather stations are a big part of this ... which is commonly used by the ESP8266 when running in AP mode. The hunch proved to be correct, and opening the device revealed an ESP-WROOM-2 running ...

[Alex Jensen] wanted to build a battery-powered weather station, using an ESP8266 breakout board to connect to WiFi. However, [Alex]’s research revealed that the ESP chip uses around 70mA per ...