import RPi.GPIO as gpio
import time


def init():
    gpio.setmode(gpio.BOARD)
    gpio.setup(7, gpio.OUT)
    gpio.setup(11, gpio.OUT)
    gpio.setup(13, gpio.OUT)
    gpio.setup(15, gpio.OUT)
    gpio.output(7, True)
    gpio.output(11, True)

def forward(tf):
    gpio.output(13, True)
    gpio.output(15, False)
    time.sleep(tf)

def reverse(tf):
    gpio.output(13, False)
    gpio.output(15, True)
    time.sleep(tf)


init()
forward(0.5)
reverse(0.5)

gpio.cleanup()
		

Here's our script with a bit more built up. First, we have an init() function, which stands for initialization.

The init function sets up all of the pins that we are using.

Next, we define our forward and reverse functions. What these functions are going to do is initiate the proper changes to make the wheels go either forward, or reverse, depending on our goals.

Finally, after defining our functions, we call a quick init(), then ask the forward and reverse functions to run for 0.5 seconds. After this, we use gpio.cleanup() to cease the pins form being activated.

We are saving this script as robot2.py

To run:

sudo python robot2.py