The sketch uploads temperature and humidity measurements read from a low-cost DHT11 device.
The data pin of the device is connected to the GPIO2 pin of the tiny ESP-01 board. The DHT11 shares the 3.3 power with the ESP-01.
You need to fill the file template_secret.h using you data, and rename it as secret.h.
The sketch has been successfully tested using the ESP-01 development board available on github as esp01-devboard.