https://cdn-shop.adafruit.com/product-files/3199/MiCS-5524.pdf
https://learn.adafruit.com/adafruit-mics5524-gas-sensor-breakout
https://learn.adafruit.com/raspberry-pi-analog-to-digital-converters/ads1015-slash-ads1115
http://learn.acrobotic.com/uploads/esp8266_devkit_pinout.png
https://learn.sparkfun.com/tutorials/using-the-logic-level-converter