Perhaps the simplest connection that you can make to the GPIO on Raspberry Pi is to connect to a pin so that you can send a simple digital output voltage. To do this, you will use the GPIO IO pins to light up an LED. To be successful, you'll need four pieces of hardware: a solder-less breadboard, some jumper wires, an LED, and a resistor. Here are more details on these parts:
A breadboard is a simple device that lets you easily connect your various electronic parts. They come in various sizes, shapes, and colors. Here is a picture of such a breadboard:
They are available at many online outlets and hobby shops.
Jumper wires are designed to connect your various electronics parts. These are specified by female or male ends, depending on the type of connection. Here is a picture of a male to female jumper wire, with the ends labeled:
For these projects, you'll want some female to male jumper cables and some female to female jumper cables.
A Light Emitting Diode...
