CO2 sensor, humidity sensor, and BMP180 connected to ESP8266 (ESP-12)
ESP8266 running NodeMCU with a DHT11 to report humidity and a BMP180 to report pressure and temperature. The Sensor also reports battery voltage which is 2xAA batteries. Photo: http://imgur.com/hDpeNxj
Room temperature, relative humidity and Barometric pressure test using an ESP8266 with DHT11 and a BMP180.