Now that we have implemented our first example, let's discuss some possible applications of being able to control the GPIO. We could use the Raspberry Pi's GPIO to control the lights in our homes. We will make use of the same example to control a table lamp!
There is a product called the PowerSwitch Tail II (http://www.powerswitchtail.com/Pages/default.aspx) that enables interfacing AC appliances like a table lamp to a Raspberry Pi. The PowerSwitch Tail comes with control pins (that can take a 3.3V high signal) that could be used to turn on/off a lamp. The switch comes with the requisite circuitry/protection to interface it directly to a Raspberry Pi Zero:
The Pi Zero interfaced to the PowerSwitch Tail II ...
