Raspberry Pi Lab

Tag: script

A Three LED Blink

by on Jan.03, 2014, under Code

My first RPi circuit.

My first RPi circuit.

My first actual circuit is a three LED blinking system.  It is a pretty simple circuit.  I have a ground pin coming off the GPIO to the blue rail on the bread board.  Then a red LED on pin 25, a green LED on pin 24, and a blue LED on pin 18.  Each LED has a 560 ohm resister.

The Python code then cycles through each LED making them blink in sequence.

It isn’t a complicated circuit or a complicated program.  However, it is an excellent starting point and a great “Hello World” program.

In my next post, I’ll use the same circuit to indicate when I have new messages waiting in my GMail account.  Should be fun.

Here is the code I used…

#!/usr/bin/env python
 
import RPi.GPIO as GPIO, time
 
DEBUG = 0
PAUSE = 1
 
GPIO.setmode(GPIO.BCM)
RED_LED = 25
GREEN_LED = 24
BLUE_LED = 18
GPIO.setup(RED_LED, GPIO.OUT)
GPIO.setup(GREEN_LED, GPIO.OUT)
GPIO.setup(BLUE_LED, GPIO.OUT)

while True:
        if DEBUG:
                print "LED ON."

        GPIO.output(RED_LED, True)
        GPIO.output(GREEN_LED, False)
        GPIO.output(BLUE_LED, False)

        time.sleep(PAUSE)

        if DEBUG:
    	print"LED OFF"

        GPIO.output(RED_LED, False)
        GPIO.output(GREEN_LED, True)
        GPIO.output(BLUE_LED, False)

        time.sleep(PAUSE)

        GPIO.output(RED_LED, False)
        GPIO.output(GREEN_LED, False)
        GPIO.output(BLUE_LED, True)

        time.sleep(PAUSE)

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RPi GPIO Setup Script

by on Jan.02, 2014, under Code, Installation

I figure I’ll be setting up and re-setting up RPi units for the forseeable future, so I converted my last post on installing the Python libraries for the GPIO into a Bash script.

Copy and paste the code to a text file in your home directory and make sure it is executable with ‘chmod +x filename’.  Then cd into your home directory and ‘./filename’ to run the script.

Here is the code…

#!/bin/bash

#####################################
# Setup the Raspberry Pi GPIO       #
# Script:  R00t  root@bjbranson.com #
# Version: 1 January 2014  V1.0     #
#                                   #
# Change Log: V1.0  Initial Script  #
#                                   #
#####################################

#########################
# CONFIGURATION SECTION #
#########################
mydir=$HOME/RPiDev

######################################
# Make sure the repository source is #
# up-to-date.                        #
######################################
echo '[I] Updating repository sources. Be Patient!'
sudo apt-get -qq update

#######################################
# Make sure the git utility is both   #
# installed and at the latest version #
#######################################
echo "[I] Verifying latest version of 'git' is installed."
sudo apt-get -y -q install git

#######################################
# Download the AdaFruit Rapberry Pi   #
# Python development libraries then   #
# list the directory to show that the #
# files were successfully downloaded  #
#######################################
if [ -d "$mydir" ]; then
   echo '[W] Specified download directory already exists.'
   echo '[I] Download of AdaFruit Python libraries skipped.'
else
   echo '[I] Downloading Python libraries from AdaFruit.'
   mkdir $mydir
   cd $mydir
   git clone http://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code.git
   cd $mydir/Adafruit-Raspberry-Pi-Python-Code
   ls
fi

#########################################
# Download and install Python libraries #
# for controlling the RPi's GPIO        #
#########################################
echo '[I] Installing Python Dev libraries for the RPi GPIO'
sudo apt-get -y -q install python-dev
sudo apt-get -y -q install python-rpi.gpio
sudo apt-get -y -q install python-pip


#################
## END OF FILE ##
#################

 

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