“This is a tiny ESP8266 based dash-button. It stays in deep sleep, once you press the button it performs a GET request to the specified URL and if configured also passes the supply voltage as a variable. The best part is that by simply bridging two pins you can make it enter configuration mode. Allowing you to change all the settings without reprogramming.
For following along this instructable I am assuming you know some things, like; how to solder, how to follow a schematic and how to upload a program and SPIFFS data to an ESP.”