Transcript Passive Infrared Sensor - Python with Raspberry Pi

Passive Infrared Sensor

The PIR Sensor
detects motion
Copyright (c) 2017 by Dr. E. Horvath
Passive Infrared Sensor
Copyright (c) 2017 by Dr. E. Horvath
PIR Sensor Circuit
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Leads left to right on the back of the PIR Sensor
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Breadboard locations
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GND VCC OUT
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j1 j2 j3
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breadboard location f2 jumper wire to 3.3 V PWR (Pin 1)
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breadboard location f3 jumper wire to GPIO 17 (Pin 11)
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breadboard location f1 jumper wire to GND (Pin 6).
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Connect the GND last.
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Remove the GND first, when taking the circuit apart.
Copyright (c) 2017 by Dr. E. Horvath
PIR Sensor Circuit
Copyright (c) 2017 by Dr. E. Horvath
Passive Infrared Sensor
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from time import sleep
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import RPi.GPIO as GPIO
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GPIO.setmode(GPIO.BCM)
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Import the GPIO library to interact with the GPIO
Set to the Broadcom mode to access the pins by the functions
PIR = 17
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Monitor GPIO 17
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GPIO.setup(PIR, GPIO.IN)
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try:
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while True:
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print("Waiting...")
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sleep(0.1)
# Do not use up CPU cycles
Passive Infrared Sensor
if GPIO.input(PIR) == 1:
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print("PIR detected")
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sleep(1)
else:
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print("Waiting for passive infrared sensor")
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sleep(0.1)
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except KeyboardInterrupt:
print(“Exiting ...”)
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finally:
GPIO.cleanup()
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Set the pins back to a safe state
Sending emails
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import smtplib
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from email.mime.text import MIMEText
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fromaddr = 'Your email address'
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toaddr = 'Reciever email address'
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username = 'Your email address'
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password = 'Your password'
Copyright (c) 2017 by Dr. E. Horvath
Sending emails
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Create a gmail account
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Go to https://www.google.com/settings/security/lesssecureapps
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Access for less secure apps Turn on
Copyright (c) 2017 by Dr. E. Horvath
Sending emails
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msg = MIMEText('This Raspberry PI stuff is awesome')
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msg['Subject']='PYTHON WITH RASPBERRY PI ANOTHER TEST'
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msg['From'] = fromaddr
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msg['To'] = toaddr
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server = smtplib.SMTP('smtp.gmail.com:587')
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server.ehlo()
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server.starttls()
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server.login(username,password)
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server.send_message(msg)
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server.quit())
Copyright (c) 2017 by Dr. E. Horvath
LEDs
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Color
Maximum Voltage (check datasheets)
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Red
2V
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Green/Yellow/Orange 2.2V
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Blue/White 3.7V
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Violet
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Ultraviolet
4.4V
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Infrared
1.6V
4V
Ohm's Law
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V = IR
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Voltage = Current * Resistance
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Current – measured in Ampheres
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Use mA in the lab
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1000mA = 1A
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1mA = 0.001A
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Resistance – measured in Ohms
Copyright (c) 2017 by Dr. E. Horvath
Ohm's Law
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Maximum current on any GPIO pin 16mA
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Output from a GPIO pin is 3.3 V
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3.3V – 2.2V = 1.1V
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2.2V to power the green LED
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V = IR
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1.1V = 16 * 0.001 * R
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R = 1.1/(16 *0.001) = 68.75 Ohms for maximum brightness
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The minimum you should use is 100 Ohms
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Use higher resistance over 1KOhm when experimenting
Copyright (c) 2017 by Dr. E. Horvath
Compute the Current
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I = V/R
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I = 1.1/R
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R is your resistor's value in Ohms
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Refer to the color chart
Copyright (c) 2017 by Dr. E. Horvath
Resistor Color Chart
Copyright (c) 2017 by Dr. E. Horvath
Four Band Resistor Code
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Bands 1 and 2
Band 3
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First Digit and Second Digit
Multiplier or Number of Zeroes
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Black 0
Black * 1
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Brown 1
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Red 2
Brown * 10
Red * 100
Orange * 1,000
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Orange 3
Yellow * 10,000
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Yellow 4
Green * 100,000
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Green 5
Blue * 1000,000
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Blue 6
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Purple 7
White * 100,000,000
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White 8
Gray * 1,000,000,000
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Gray 9
Gold *0.1
Purple * 10,000,000
Copyright (c) 2017 by Dr. E. Horvath
Silver * 0.01
Four Band Resistor Code
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Band 4 Percent Tolerance
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Purple
0.1%
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Black -
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White
-
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Brown
1%
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Gray
-
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Red
2%
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Gold
5%
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Orange
-
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Silver
10%
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Yellow
-
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No color 20%
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Green
0.5%
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Blue
0.25%
Copyright (c) 2017 by Dr. E. Horvath
Connecting an LED
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Light emitting diode (LED) connections
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Longer lead is positive (anode) breadboard location j24
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Shorter lead is negative (cathode) breadboard location j22
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1.2KOhm Resistor
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breadboard location i30
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breadboard location i24
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breadboard location h30 jumper wire to GPIO 22 (Pin 15)
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breadboard location f22 jumper wire to GND (Pin 9)
Copyright (c) 2017 by Dr. E. Horvath
Connecting an LED
Copyright (c) 2017 by Dr. E. Horvath
Turning on an LED
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import RPi.GPIO as GPIO
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green_led = 23
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GPIO 23
GPIO.setup(green_led,GPIO.OUT)
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Set the pin to be an output
GPIO.output(pin_number,True)
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Turn on the LED
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sleep(interval)
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GPIO.output(pin_number,False)
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sleep(interval)
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Turn off the LED
GPIO.cleanup()
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Set the GPIOs back to a safe state
Copyright (c) 2017 by Dr. E. Horvath