SunFounder PiCar-X Kit - Obstacle Avoidance

SunFounder PiCar-X Kit
4.6 4. Obstacle Avoidance
In this project, PiCar-X will detect obstacles in front of it while moving forward, and when the obstacles are too close,
it will change the direction of moving forward.
Run the Code
cd ~/picar-x/example
sudo python3 4.avoiding_obstacles.py
After running the code, PiCar-X will walk forward.
If it detects that the distance of the obstacle ahead is less than 20cm, it will go backward.
If there is an obstacle within 20 to 40cm, it will turn left.
If there is no obstacle in the direction after turning left or the obstacle distance is greater than 25cm, it will continue to
move forward.
Code
Note: You can Modify/Reset/Copy/Run/Stop the code below. But before that, you need to go to source code path
like picar-x/example. After modifying the code, you can run it directly to see the effect.
from picarx import Picarx
import time
POWER = 50
SafeDistance = 40 # > 40 safe
DangerDistance = 20 # > 20 && < 40 turn around,
# < 20 backward
def main():
try:
px = Picarx()
# px = Picarx(ultrasonic_pins=['D2','D3']) # tring, echo
while True:
distance = round(px.ultrasonic.read(), 2)
print("distance: ",distance)
if distance >= SafeDistance:
px.set_dir_servo_angle(0)
px.forward(POWER)
elif distance >= DangerDistance:
px.set_dir_servo_angle(30)
px.forward(POWER)
time.sleep(0.1)
else:
px.set_dir_servo_angle(-30)
px.backward(POWER)
time.sleep(0.5)
finally:
px.forward(0)
(continues on next page)
58 Chapter 4. Play with Python