ESP8266-13 with a BME280 from Adafruit. Powered by a lipo battery (2,000mAh).
Water softener salt level monitor. Sensor uses ESP8266-12 & HC-SR04 ultrasonic sensor. Remote uses ESP8266-12e & Nokia 5110 LCD to display the level.
My first attempt to build a weather station based on an ESP8266 and some common sensors. These values show the irrigation related part of the sensor readings.