Hi, I have "made" an air quality sensor by using a MH-Z19 module bought on Aliexpress for around 25 USD and a ESP8266 201 board. Sensor http://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20160624103205&SearchText=MH-z19 The code is updating a dummy air quality sensor around every 30 ...