When i thought about exploring the GPIO (general purpose input output) of raspberry pi, I had so many doubts on where to start. In the end nothing works better than working via simple examples. The following is a very basic sample which does the yellow and green led blinking.
Yellow LED = PIN NO. 23
Green LED = PIN NO. 18
Following is the breadboard layout.
Following is simple python based program.
#!/usr/bin/env python import RPi.GPIO as GPIO ## Import GPIO library import time ## Import 'time' library. Allows us to use 'sleep' GPIO.setmode(GPIO.BCM) GREEN_LED = 18 YELLOW_LED = 23 GPIO.setup(GREEN_LED, GPIO.OUT) GPIO.setup(YELLOW_LED, GPIO.OUT) GPIO.output(GREEN_LED,False) GPIO.output(YELLOW_LED,False) ##Define a function named Blink() def Blink(numTimes,speed): for i in range(0,numTimes):## Run loop numTimes print "Iteration " + str(i+1)## Print current loop GPIO.output(GREEN_LED,True) GPIO.output(YELLOW_LED,True) time.sleep(speed) GPIO.output(GREEN_LED,False) GPIO.output(YELLOW_LED,False) time.sleep(speed) print "Done" ## When loop is complete, print "Done" GPIO.cleanup() ## Ask user for total number of blinks and length of each blink iterations = raw_input("Enter total number of times to blink: ") speed = raw_input("Enter length of each blink(seconds): ") ## Start Blink() function. Convert user input from strings to numeric data types and pass to Blink() as parameters Blink(int(iterations),float(speed))