Sometimes, all you need is a quick program that needs to send some sensor data from a location that you don’t want or can’t put a power cable to.
Battery power, sending an ESP8266 into deepsleep for most of the time can be the answer.
The program here does just that. For reasons of speed it uses a static IP set up.
Dont forget to connect GPIO16 to the RST pin on your ESP8266. A bare ESP8266 is your best choice. If you are using an ESP8266-01, you will need to have good eyes to solder a wire between pin 16 and the RST pin.
You can download the full program here.