If you need a reminder about resistors in general, you can take a look at my resistors article. Floating pins Pull resistors are used to solve the problem of floating pins, so let’s briefly explain what that is. In the following diagram, we have a simple IC (Integrated Circuit) that works with 5V and has a single GPIO (General Purpose Input/Output) pin: If we use the GPIO pin for input, it will read HIGH or LOW depending on the input voltage. The problem is that if we write a program that read...