Obstacle Avoidance

In this project, picrawler will use an ultrasonic module to detect obstacles in front. When PiCrawler detects an obstacle, it will send a signal and look for another direction to move forward.

Run the Code

cd /home/pi/picrawler/examples
sudo python3 avoid.py

After the code runs, PiCrawler will walk forward. If it detects that the distance of the obstacle ahead is less than 10cm, it will stop and sound a warning, then turn left and stop. If there is no obstacle in the direction after turning left or the obstacle distance is greater than 10, 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 picrawler\examples. After modifying the code, you can run it directly to see the effect.

from picrawler import Picrawler
from robot_hat import TTS, Music
from robot_hat import Ultrasonic
from robot_hat import Pin
import time
import os

tts = TTS()
music = Music()

crawler = Picrawler([10,11,12,4,5,6,1,2,3,7,8,9])
#crawler.set_offset([0,0,0,0,0,0,0,0,0,0,0,0])
sonar = Ultrasonic(Pin("D2") ,Pin("D3"))

alert_distance = 15

speed = 100

def main():
    distance = sonar.read()
    print(distance)
    if distance < 0:
        pass
    elif distance <= alert_distance:
        try:
            music.sound_effect_threading('./sounds/sign.wav')
        except Exception as e:
            print(e)
        crawler.do_action('turn left angle',3,speed)
        time.sleep(0.2)
    else :
        crawler.do_action('forward', 1,speed)
        time.sleep(0.2)


if __name__ == "__main__":
    while True:
        main()

How it works?

You can get the distance by importing the Ultrasonic class.

from robot_hat import Ultrasonic

Then initialize the ultrasonic pins.

sonar = Ultrasonic(Pin("D2") ,Pin("D3"))

Here is the main program.

• Read the distance detected by ultrasonic module and filter out the values less than 0 (When the ultrasonic module is too far from the obstacle or cannot read the data correctly, distance<0 will appear).

• When the distance is less than or equal to alert_distance (the threshold value set earlier, which is 10), play the sound effect sign.wav. PiCrawler does turn left angle .

• When the distance is greater than alert_distance, PiCrawler will move forward.

distance = sonar.read()
print(distance)
if distance < 0:
    pass
elif distance <= alert_distance:
    try:
        music.sound_effect_threading('./sounds/sign.wav')
    except Exception as e:
        print(e)
    crawler.do_action('turn left angle',3,speed)
    time.sleep(0.2)
else :
    crawler.do_action('forward', 1,speed)
    time.sleep(0.2)

Note

You can add different sound effects or music to musics or sounds folder via Filezilla Software.