Hi @Merlotmaker, If you want more reactions from members, you should provide more information. what for sensor do you have, because you are speaking about BMP280 and BME280 the lib you are referring to is a specific one for the https://www.sparkfun.com/products/13676 how did you connect your sensor to the UNO? did you follow this guide already? https://learn.sparkfun.com/tutorials/sparkfun-bme280-breakout-hookup-guide