If you get this error:
avrdude: Yikes! Invalid device signature. Double check connections and try again, or use -F to override this check.
It can mean one of two things:
- You have the wrong board selected from the
Tools > Boardmenu.
- You're not using the right version of avrdude. Arduino uses a slightly modified version of avrdude to upload sketches to the Arduino board. The standard version queries for the board's device signature in a way not understood by the bootloader, resulting in this error. Make sure you're using the version of avrdude that comes with the Arduino IDE.