Raspberry Pi Lab

Tag: RPi

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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Confused?

by on Dec.27, 2013, under Installation, Troubleshooting

So I tested the HDMI output on the RPi by connecting it to the HDMI cable coming from one of the regular computers to a television.  There is nothing wrong with the RPi.

Re-tested the HDMI to VGA converter on the same television and it works also.

Recall, from my previous posts, I already tested the monitor on the iPad’s VGA adapter.

So if the RPi works and the HDMI converter works, and the VGA cable works, and the monitor works, then why don’t they all work together?

Back to the thinking box!

 

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Which Linux Distro?

by on Dec.25, 2013, under Operating Systems

Well, with Linux, there is not one right answer.  The only that that is for certain is that the Linux distro chosen must be for an ARM processor.  That means my personal favorite desktop and server distro, Ubuntu, is out of the running.

But there are good options.

The absolute best option would be Gentoo.  Start from the absolute bare bottom and custom compile the entire operating system specifically for the piece of hardware on which it is running.  While that would be the best option, I don’t have the time or desire to spend hours (perhaps days) tweaking, compiling, and re-compiling absolutely everything, so Gentoo isn’t an option for me.  At least not right now.

The Raspberry Pi Foundation recommends a customized variant of Debian Linux they call Raspbian Linux.  It is a distro specifically optimized for the Raspberry Pi.  Sounds like a good option.

However, Ada Fruit recommends a Raspbian variant she calls Occidentalis Linux.  It is a Raspbian base that has been further optimized and tweaked for building and controlling your own DIY circuits.

So, If you are going to build something that doesn’t require controlling an external circuit, then go with Raspbian.  But I want to build stuff, so I am going to start with Occidentalis Linux.

Tell me about the distro you use and why you chose it.

 

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Total N00b

by on Dec.24, 2013, under Uncategorized

raspberrypiWell, I am a complete and total n00b with respect to the Raspberry Pi, but I am anxious to learn.

Actually, I’m not new to computers.  I’m 41 and got hold of my first computer in the 5th grade.  I’ve never looked back.  I have loved computers ever since that first day.

I have a B.S. in Management Information Systems and have worked as a tech on a help desk, an Internet programmer, and a Systems/Network administrator.  So this isn’t my first rodeo.

But I am completely new to the Raspberry Pi and building computer controlled circuits.

This blog is going to be my notebook.  As I explore, experiment, and learn, I am going to write about it here.  Together, you and I will explore the Raspberry Pi and learn what it can do.

I’m excited to get this journey started.

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