(Youtube Video: Star Trek Type 4B Computer Replica, by Jeff Kaler, displaying various switches)
For a century and a half, it is the mechanical switch that has allowed interaction between us humans and the machines we build. On/off, the switch is ultimately what we modelled to build computers which contain millions of tiny silicon switches to calculate in binary.
The old-fashioned switches are still very important today in nearly any project.
You'd think the use of an external switch for triggering actions with your project is straightforward enough. You connect a push button or toggle switch to a microcontroller and . . . and perhaps nothing.
Using switches is great - we encourage you to do so! Here are some tips for getting your project working effectively so you can work on other things besides a cranky switch.