Controlling LED with Raspberry Pi
Here you can found basic example of controlling an LED from Raspberry Pi.
Switching LED on/off from Raspberry Pi console
Follow instructions for how to turn the LED on/off from command line. In this example the LED is connected to GPIO pin 18.
You can connect the LED to any other GPIO pin as well.
#Switching LED on/off from Raspberry Pi console $echo 18> /sys/clas/gpio/export $cd /sys/class/gpio/gpio18 #set pin 18 direction to out $echo out > direction #Turn LED on $echo 1 > value # Turn LED off $echo 0> value
Python program for blinking LED
Given below python code for blinking an LED connected to raspberry Pi every second. The code uses th RPi.GPIO module to control the GPIO on raspberry Pi. In this program we set pin 18 direction to output and then write True/False alternatively after a delay of one second.
# python program for blinking LED import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BCM) GPIO.setup(18,GPIO.OUT) while True: GPIO.output(18,True) time.sleep(1) GPIO.output(18, False) time.sleep(1)
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Interfacing an LED an Switch with Raspberry Pi
In this example the LED is connected to GPIO pin 18 and switch is connected to pin 25. In the infinite while loop the value of pin 25 is checked and the state of LED is toggled if the switch is pressed. This example shows how to get input from GPIO pins and process the input and take some action. The action in this example is toggling the state of an LED.
# Interfacing an LED and Switch with Raspberry Pi from time import sleep import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) # Switch Pin GPIO.setup(25, GPIO.IN) #LED Pin GPIO.setup(18, GPIO.OUT) state=false def toggleLED(pin): state = not state GPIO.output(pin, state) while True: try: if (GPIO.input(25) == True): toggleLED(pin) sleep(.01) expect KeyboardInterrupt: exit()
Python program for sending an email on switch press
Let us look at another example, in which the action is an email alert.
#python program for sending an email on switch press import smtplib from time import sleep import RPi.GPIO as GPIO from sys import exit from_email = '' receipients_list = ['receipient-email'] cc_list= subject = 'hello' message = 'Switch pressed on raspberry Pi' username = '' password = '' server = 'smtp.gmail.com:587' GPIO.setmode(GPIO.BCM) GPIO.setup(25, GPIO.IN) def sendmail (from_addr , to_addr_list, cc_addr_list, subject, message, login, password, smtpsever): header = 'from : %s \n' %from_addr header += 'To: %s \n' %',' .join(to_addr_list) header += 'Cc: %s \n' % ',' .join (cc_addr_list) header += 'subject: %s \n\n' % subject message = header +message server = smtplib.SMTP(smtpserver) sever.starttls() sever.login (login,password) problems = server.sendmail (from_addr, to_addr_list, message) server.quit() while True: try: if (GPIO.input(25) ==true): sendmail(from_email, receipients_list, cc_list, subject, message, usernmae, password, server) sleep(.01) expect KeyboardInterrupt: exit()
I hope you like this example tutorial Controlling LED with Raspberry Pi.
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