Raspberry Pi and Sensors

In this activity we are going to integrate a range of sensors.

First, we will use the HC-SR04 Ultrasonic Module Distance Measuring Sensor to measure distance.

Start by referring to the Raspberry Pi pinout.

A Raspberry Pi 3 Pinout

Now carefully examine the circuit diagram that we will be using below.

File:Sr04 circuit.png

A circuit diagram of the SR04 Wiring

Finally, examine the picture below to confirm your understanding. You may want to click on ti to get a high res version.

File:Sr04 picture.png

A picture of a Raspberry Pi Zero, wired to an SR04

#!/usr/bin/python3

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)

TRIG = 23
ECHO = 24

print("Distance Measurement In Progress")

GPIO.setup(TRIG,GPIO.OUT)
GPIO.setup(ECHO,GPIO.IN)

GPIO.output(TRIG, False)

print("Waiting For Sensor To Settle")

time.sleep(2)

GPIO.output(TRIG, True)
time.sleep(0.00001)

GPIO.output(TRIG, False)

while GPIO.input(ECHO)==0:

  pulse_start = time.time()

while GPIO.input(ECHO)==1:

  pulse_end = time.time()      

pulse_duration = pulse_end - pulse_start

distance = pulse_duration * 17150

distance = round(distance, 2)

print("Distance:",distance,"cm")

GPIO.cleanup()