Added ultrasound sensor script

mappingbot/ultrasound.py

+# Libraries
+import RPi.GPIO as GPIO
+import time
+
+# GPIO Mode (BOARD / BCM)
+GPIO.setmode(GPIO.BCM)
+print(GPIO.VERSION)
+
+
+class UltrasoundSensor:
+    SONIC_SPEED = 343  # Speed of sound in m/s
+
+    def __init__(self, name, trigger_pin: int, echo_pin: int):
+        self.name = name
+        self.trigger_pin = trigger_pin
+        self.echo_pin = echo_pin
+
+        # Setup GPIO pins
+        GPIO.setup(self.trigger_pin, GPIO.OUT)
+        GPIO.setup(self.echo_pin, GPIO.IN)
+
+    def get_distance(self) -> float:
+        GPIO.output(self.trigger_pin, True)  # Fire ultrasound pulse
+
+        # Store initial time
+        pulse_sent = time.time()
+        pulse_received = time.time()
+
+        time.sleep(0.00001)  # Wait for a very small time
+        GPIO.output(self.trigger_pin, False)  # Stop firing the pulse
+
+        while GPIO.input(self.echo_pin) == 0:  # Record the exact time the pulse was sent
+            pulse_sent = time.time()
+
+        while GPIO.input(self.echo_pin) == 1:  # Record the exact time the pulse was received
+            pulse_received = time.time()
+
+        time_elapsed = pulse_received - pulse_sent  # time difference between sending and receiving pulse
+        return (time_elapsed * self.SONIC_SPEED) / 2  # We divide by two because of the reflection of the wave
+
+    def print_distance(self, unit='cm') -> None:
+        if unit == 'm':
+            dist = self.get_distance()
+            print("%12s measured %0.3f m" % (self.name, dist))
+        else:  # Unit is cm or not recognised
+            dist = self.get_distance() * 100.0
+            print("%12s measured %0.1f cm" % (self.name, dist))
+
+
+if __name__ == '__main__':
+    try:
+        sensor1 = UltrasoundSensor(name="sensor1", trigger_pin=17, echo_pin=16)
+        sensor2 = UltrasoundSensor(name="sensor2", trigger_pin=27, echo_pin=20)
+        sensor3 = UltrasoundSensor(name="sensor3", trigger_pin=22, echo_pin=21)
+        while True:
+            sensor1.print_distance(unit='cm')
+            sensor2.print_distance(unit='cm')
+            sensor3.print_distance(unit='cm')
+            time.sleep(1)
+
+    except KeyboardInterrupt:  # Exit by pressing CTRL + C
+        print("Measurement stopped by User")
+    finally:  # Always clean up the pins
+        GPIO.cleanup()