yourpi:~$ wget https://project-downloads.drogon.net/wiringpi-latest.deb

NOTE: domain say “dr-OH-gon”, it does NOT say “dragon”

yourpi:~$ sudo dpkg -i wiringpi-latest.deb

“gpio readall” will open up a table showing the physical pin layout of your pi. It will also tell you whether a pin is set to input or output, and whether the pin is turned on or off (V=0 shows the pin is off, v=1 shows the pin is on).

“gpio mode WIRINGPI_PIN# MODE” will change the mode of the designated pin. You must use the WiringPi pin number. Mode can either be in (input) or out (output).

“gpio write WIRINGPI_PIN# STATE” will change the ON/OFF state of a pin. 0=off and 1=on

The ground “pin” is extremely important if connecting a circuit together. If done without a ground you can easily fry your breadboard or even kill an L.E.D light. Your ground pins are indicated by a GND next to the designated pin. For every power source connection, you must have a ground wire going to one of the Negative column.

A resistor is a component that slows down the flow of electrons through an electrical circuit. The specified resistance value can be decoded by looking at the coloured bands that surround the body of the resistor.

GPIO.0 is actually GPIO17 on your T-cobbler

Brief Definition:

A light-emitting diode (LED) is a semiconductor device that emits light
when current flows through it.

Light-emitting diodes only allow electrical current to pass through them one way. The longer lead is the positive connection, and the shorter lead is the negative connection.