라즈베리 파이 - 초음파 거리 센서 2

3.3-5V 이나 5V추천

탐지거리 3cm-4m

[링크 : http://www.seeedstudio.com/depot/Grove-Ultrasonic-Ranger-p-960.html]

다른 소스들의 예제와 다르게 이녀석...

Trigger / Echo가 아닌 Signal 하나 뿐이다

그래서 Trigger로 output 모드 설정후 전송하고 재빠르게

Echo로 input 모드로 설정후 받아 시간을 재도록 수정해야 한다.

포트는 만만한(?) GPIO18번 PWM 포트(wiring pi 기준 1번)으로 설정

흰색 - 5V

검정 - GND

보라 - GPIO18 ->A0

$ cat ultrasonic_1.py #!/usr/bin/python #+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ #|R|a|s|p|b|e|r|r|y|P|i|-|S|p|y|.|c|o|.|u|k| #+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ # # ultrasonic_1.py # Measure distance using an ultrasonic module # # Author : Matt Hawkins # Date   : 09/01/2013 # ----------------------- # Import required Python libraries import time import RPi.GPIO as GPIO # Use BCM GPIO references # instead of physical pin numbers GPIO.setmode(GPIO.BCM) # Define GPIO to use on Pi GPIO_TRIGGER = 18 GPIO_ECHO    = 18 print "Ultrasonic Measurement" # Set pins as output and input GPIO.setup(GPIO_TRIGGER,GPIO.OUT)  # Trigger # Set trigger to False (Low) GPIO.output(GPIO_TRIGGER, False) # Allow module to settle time.sleep(0.5) # Send 10us pulse to trigger GPIO.output(GPIO_TRIGGER, True) time.sleep(0.00001) GPIO.output(GPIO_TRIGGER, False) start = time.time() GPIO.setup(GPIO_ECHO,GPIO.IN)      # Echo while GPIO.input(GPIO_ECHO)==0:   start = time.time() while GPIO.input(GPIO_ECHO)==1:   stop = time.time() # Calculate pulse length elapsed = stop-start # Distance pulse travelled in that time is time # multiplied by the speed of sound (cm/s) distance = elapsed * 34300 # That was the distance there and back so halve the value distance = distance / 2 print "Distance : %.1f" % distance # Reset GPIO settings GPIO.cleanup()

자가 없어서 대충 한뼘(21cm)로 해봤는데 얼추 맞는 기분

pi@raspberrypi ~/src/sonic $ sudo python ultrasonic_1.py Ultrasonic Measurement Distance : 154.8 pi@raspberrypi ~/src/sonic $ sudo python ultrasonic_1.py Ultrasonic Measurement Distance : 3.0 pi@raspberrypi ~/src/sonic $ sudo python ultrasonic_1.py Ultrasonic Measurement Distance : 9.1 pi@raspberrypi ~/src/sonic $ sudo python ultrasonic_1.py Ultrasonic Measurement Distance : 26.3

대충 소스 받아서 수정

[링크 : http://www.raspberrypi-spy.co.uk/2012/12/ultrasonic-distance-measurement-using-python-part-1/]