Super basic electronics lesson: if you have an input on being monitored, it must have something connected to it. Connect the pin to earth and you'll see that everything is fine.
@D0nny94 As for the tachometer. If you do ne[…]
Thanks Eric for pointing me to that one, basical[…]
... Thanks for picking this up - some good wo[…]
Use secondary serial. See the wiki for info on the[…]