Using Raspberry Pi to drive motion sensor and turn on LED

Overview

Generally speaking, motion sensor is made of thermoelectric sensor, and it can detect body motion. The motion sensor module generally uses the BISS0001 (“Micro Power PIR Motion Detector IC”) to convert the analog signal from the sensor to digital output.

Experimental principle of this project is that, when the detection of the human body motion, GPIO output get high level and light is on; else, GPIO output would get low level and LED would be off. In this project, Python Language will help us achieve this experiment. Enjoy Raspberry Pi Python programming tour with us.

Experimental photo

Experimental Parts

• Raspberry Pi board

  x1

• Motion Sensor

  x1

• LED

  x1

• Jumper wire

  centain amount

• breadboard

  x1

• 1KΩ resistor

  x1

• T-type GPIO Extension Board40 Pin Ribbon Cable

  optional

Circuit Graph

Motion sensor Schematic

Motion sensor Interface Layout

The two potentiometer can adjust delay time and sensitivity, as the follow picture:

Software

(1)Before Python programming, Install GPIO library and Python library file in raspberry pi:

open terminal, update the apt-get software installation package list (Note: Network must be connected), and then enter installation command to install the raspberry gpio-python package.

Follow the next commands to complete installation, after entering each commands in terminal, press “enter” to complete:

a) update software list command: sudo apt-get update

b) install python command: sudo apt-get install python-dev

c) install python-pip command (python-pip is a manager for python software package): sudo apt-get install python-pip

d) Install rpi.gpio with pip command: sudo pip install rpi.gpio

e) testing Command: sudo python

After all steps, you will see the following photo. It means it is successful to install GPIO library and Python library file. You can begin to program this project via Python

(2)Programming

You can compile code not only through connecting monitor with your Pi, also through SSH. You can choose two methods to compile the project code.

A. File editor to compile code:

1)create a new file “led.py” in any direction (such as “/home/pi/”）: enter the command sudo touch led.py and then press enter

2)Open file “led.py”: enter the command sudo nano led.py and then press enter

3)paste the following code in the file “led.py”

#turns on and off a light emitting diode(LED) depending on motion sensor

import RPi.GPIO as GPIO             #importing the RPi.GPIO module
import time                        #importing the time module
GPIO.cleanup()                     #to clean up at the end of your script
led_pin = 37                       #select the pin for the LED
motion_pin = 35                    #select the pin for the motion sensor
def init():
  GPIO.setmode(GPIO.BOARD)         #to specify which pin numbering system
  GPIO.setwarnings(False)   
  GPIO.setup(led_pin,GPIO.OUT)                             #declare the led_pin as an output 
  GPIO.setup(motion_pin,GPIO.IN,pull_up_down=GPIO.PUD_UP)  #declare the motion_pin as an input
  print("-----------------------------------------------------------------------")  

def main():
  while True:
    value=GPIO.input(motion_pin)  
    if value!=0:                             #to read the value of a GPIO pin
      GPIO.output(led_pin,GPIO.HIGH)                #turn on led
      time.sleep(2)        #delay 2ms
      print "LED on"                           #print information
    else:
      GPIO.output(led_pin,GPIO.LOW)                #turn off led
      time.sleep(2)       #delay 2ms
      print "LED off"                         #print information

init()
main()
GPIO.cleanup()

4) after compile the project, press “Ctrl” + “X” to save the code, enter “Y” to confirm saving, and press “enter” to exit the file editor

B. Command to compile code

Enter the command wget http://osoyoo.com/driver/led.py, and press “enter” to complete compiling code.

(3)Experiment Result:

Enter the following command: sudo python ./led.py, and press “enter” to run the project. When detection body motion, the LED turns on, else, the LED turns off, and the monitor shows as the photo: