Implement your design in Python skeleton code. That is given a class, for instan
ID: 3571917 • Letter: I
Question
Implement your design in Python skeleton code. That is given a class, for instance, car, it perhaps has methods as forward, back, right, left, and stop. Each method should have only a print statement contained within the method so that we know it was called. For example, to drive around the block requires four left turns. So, the output should look something like this:
Forward, Left, Left, Left, Left, Stop
Come up with something more difficult than driving around the block. For example drive from your house to the store and drive back.
Explanation / Answer
#!/usr/bin/env python
import time, datetime, RPi.GPIO as GPIO
FORWARD=12
BACK=11
LEFT=13
RIGHT=15
TURBO=7
GPIO.setmode(GPIO.BOARD)
#Remember to setup the GPIO pin as input or output
GPIO.setup(FORWARD, GPIO.OUT)
GPIO.setup(BACK, GPIO.OUT)
GPIO.setup(LEFT, GPIO.OUT)
GPIO.setup(RIGHT, GPIO.OUT)
def print_time(): #prints out the time now in a format we like
#print "Time before statement is run"
print datetime.datetime.now()
def forwards_on(): #turns the forwards pin on
print "About to turn forwards pin on"
print_time()
#turn back off as well
backwards_off()
GPIO.output(FORWARD,1)
def forwards_off(): #turns the forwards pin off
print "About to turn forwards pin off"
print_time()
GPIO.output(FORWARD,0)
def backwards_on(): #turns backwards pin on
print "About to turn the backwards pin on"
print_time()
#turn forwards off as well
forwards_off()
GPIO.output(BACK,1)
def backwards_off(): #turns backwards pin off
print "About to turn the backwards pin off"
print_time()
GPIO.output(BACK,0)
def left_on(): #turns the left pin on
print "About to turn the left pin on"
print_time()
#turn right off as well
right_off()
GPIO.output(LEFT,1)
def left_off(): #turns the left pin off
print "About to turn the left pin off"
print_time()
GPIO.output(LEFT,0)
def right_on(): #turns the right pin on
print "About to turn the right pin on"
print_time()
#turn left off as well
left_off()
GPIO.output(RIGHT,1)
def right_off(): #turns the right pin off
print "About tot turn the right pin off"
print_time()
GPIO.output(RIGHT,0)
def choose_dir(dirWanted=LEFT):
if dirWanted == LEFT:
right_off()
left_on()
else:
left_off()
right_on()
def straighten():
print "About to straighten"
print_time()
left_off()
right_off()
def slalom(startSideDir=RIGHT,startDir=FORWARD,turns=4, interval=0.1): #does a slalom by default starting right and doing it 4 times with an interval of 0.1
i = 0
#need to determine which way we should be going with the direction
if startDir == FORWARD:
print "Going to move forwards in the slalom"
print_time()
forwards_on()
else:
print "Going to move backwards in the slalom"
print_time()
backwards_on()
#now do the turns
while i < turns:
print "about to slalom to = ", startSideDir
choose_dir(startSideDir)
print "Left direction", LEFT
print "Right direction", RIGHT
print_time()
if i == 0:
#the first turn should only be half the amount
time.sleep(interval/2)
else:
time.sleep(interval)
#toggle direction for next time
if startSideDir == RIGHT:
startSideDir = LEFT
else:
startSideDir = RIGHT
i = i + 1
#at the end straighten the wheels
straighten()
def all_off():
GPIO.output(FORWARD,0)
GPIO.output(BACK,0)
GPIO.output(LEFT,0)
GPIO.output(RIGHT,0)
def cleanup(): #cleans up the GPIO pins
GPIO.cleanup()
def sleep(sleepTime=1):
time.sleep(sleepTime)
def main():
try:
forwards_on()
# sleep(0.6)
# right_on()
sleep(0.5)
#all_off()
slalom(LEFT,FORWARD,400,0.5)
sleep(0.5)
all_off()
sleep(0.5)
#time.sleep(0.4)
#backwards_on()
#time.sleep(1)
slalom(LEFT,BACK,4,0.5)
sleep(0.5)
#forwards_on()
#time.sleep(1)
#right_on()
#time.sleep(0.5)
#right_off()
#time.sleep(0.5)
#left_on()
#time.sleep(0.5)
#left_off()
#time.sleep(0.5)
#forwards_off()
#time.sleep(0.5)
#backwards_on()
#time.sleep(1)
all_off()
cleanup()
except KeyboardInterrupt:
cleanup()
if __name__ == "__main__":
main()