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 /home/pi/picar-x/example
sudo python3 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 25cm, 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


def main():
    try:
        px = Picarx()
        # px = Picarx(ultrasonic_pins=['D2','D3']) # tring, echo
        px.forward(30)
        while True:
            distance = px.ultrasonic.read()
            print("distance: ",distance)
            if distance > 0 and distance < 300:
                if distance < 25:
                    px.set_dir_servo_angle(-35)
                else:
                    px.set_dir_servo_angle(0)
    finally:
        px.forward(0)


if __name__ == "__main__":
    main()

How it works?

The ultrasonic module is also imported in the picarx module, and we can use some of its encapsulated functions to detect distance.

from picarx import Picarx

Because the ultrasonic module is imported into the picarx module, we can directly use px.ultrasonic.read() to get the distance.

px = Picarx()
px.forward(30)
while True:
    distance = px.ultrasonic.read()

The following code snippet reads the distance value reported by the ultrasonic module, and if the distance is below 25cm (10 inches) it will set the steering servo from 0° (straight) to -35° (turn left).

while True:
    distance = px.ultrasonic.read()
    print("distance: ",distance)
    if distance > 0 and distance < 300:
        if distance < 25:
            px.set_dir_servo_angle(-35)
        else:
            px.set_dir_servo_angle(0)