Using PullUp and PullDown Resistors on the Raspberry Pi

When you start out creating circuits with the Raspberry Pi and its GPIO pins, there’s an unexpected but important concept to understand, called “floating”. A Simple Circuit Imagine you’re creating a circuit using a breadboard. Something very simple… a button, some wire and a power source (like the 3.3v pin on the Pi). You just want to be able to click a button to complete the circuit. Maybe it looks something like this. The above circuit connects 3.3v, through a switch and 220Ω resistor, to pin #6. That won’t be very useful though, without a »