auto-bot_final

#Import libraries
from gpiozero import Robot, InputDevice, OutputDevice, DigitalInputDevice, DigitalOutputDevice
from gpiozero.tools import scaled, negated
from time import sleep, time
from signal import pause
import atexit
import random

#Define variables
robo = Robot(left=(8,7), right=(10,9))
trig = OutputDevice(17)
echo = InputDevice(18)
duration = 60
end_time = time() + duration
running = True
left_obstacle_sensor = DigitalInputDevice(27)
right_obstacle_sensor = DigitalInputDevice(4)
drive_speed = 0.6

#Wait 2 seconds before starting
sleep(2)

#Trigger/Echo pulse time function
def get_pulse_time():
    trig.on()
    sleep(0.00001)
    trig.off()

    while echo.is_active == False:
        pulse_start = time()

    while echo.is_active == True:
        pulse_end = time()

    return pulse_end - pulse_start

#Distance calculation function based on pulse time as input
def calculate_distance(duration):
    speed = 343
    distance = speed * duration / 2
    return distance

#Main loop executes until run time
while running:

    #Calculate pulse time/distance
    duration = get_pulse_time()
    distance = calculate_distance(duration)
    turn_time = random.uniform(0.1, 0.9)
    left_right = random.randint(0, 1)

    #Drive condition: either forward if no obstacles, or left
    if distance <= 0.35 and distance != 0:
        robo.backward(drive_speed)
        sleep(0.5)
        if left_right == 0:
            robo.left(drive_speed)
        else:
            robo.right(drive_speed)
        sleep(turn_time)
    else:
        #Scale motors to the opposite reading coming from the infrared sensor on the opposing side (i.e. left sensor for right motor and vice versa); should act as backup obstacle detection if ultrasonic fails
        robo.left_motor.source = scaled(right_obstacle_sensor, -1 * drive_speed, drive_speed)
        robo.right_motor.source = scaled(left_obstacle_sensor, -1 * drive_speed, drive_speed)

    #Running condition: False if over end_time
    if time() > end_time:
        running = False
        robo.stop()

    #print distance to console
    sleep(0.06)
    print(distance)