viot-esp8266-ccs811 This sensor outputs Temperature, CO2 (NOT CO), TVOC to an OLED over I2C. I used a NodeMCU dev board Aliexpress NodeMCU - https://goo.gl/sTG6Xg Aliexpress CCS811 Sensor - https://goo.gl/YZA3bA ALiexpress OLED Display used - https://goo.gl/AbNCvq