Wednesday, February 20, 2013

RaspberryPi, Boblight, and the WS2801 LED - Part 2

For the most part this tutorial follows the instructions outlined here.  
This is part 2 of my Raspberry Pi and WS2801 LED post. Part one went over the preparation and parts needed to make the LEDS and Raspberry Pi talk to each other. Part 2 will focus on putting everything together and capitalizing on  that communication.

We used a breadboard when we were prototyping the power and data connections between the RaspberryPi  and the LEDS. According to the diagram below our power is coming from an external 5V source (not from the RaspberryPis  micro usb) this is needed to properly power the LEDS.

I did a lot of scavenging and found a 5v 3amp power supply for the LEDS and the RaspberryPi. We actually had some success powering the RaspberryPi and the LEDS through USB but found that the last LEDS in the strand were a bit dimmer. In the final build we distributed the power every 10 LEDS but i'll discuss that in a later post. 

The power supply is connected into this which is then connected to the breadboard via jumper cables.
The pictures below are from our initial setup.

raspberry pi ws2801 power
We didn't use the breadboard in our final version, it was just an easy way of distributing the power and data connections without stripping cables. 

Once the LEDS are connected it's time to run some software to see if everything works correctly. 
If you followed part one of this tutorial you should have the Adafruit WebIDE installed and running at this point. We'll use this to test our LEDS. 

I had some trouble with the local name that the you're supposed to be able to access the IDE from . 
http://raspberrypi.local:3000 according to the tutorial. My local network couldn't resolve the name, but it had no trouble accessing the IDE via IP. So navigate your browser to http://YOUR-RPi-IPADDRESS:3000

If all went well you'll be greeted with this page:

The IDE requires you to sign up for a BitBucket account. Which will privately hold your code (unless you want it public) in their cloud. This worked out pretty well for me since i had to install the WebIDE a few times for it to work correctly. I wrote some custom scripts which were saved between installs on my BitBucket account. 

Once signed in navigate through the examples to

The arrow in the picture point out:

SPIDO = 17

These are the pins that the Pi is going to send data to when this python script is run.
This post here explains why were using these pins on the RaspberryPi. 

If everything looks like its in the right spot hit the 'Run' button up top. If it worked you'll see the LEDS light up RED, GREEN,  BLUE, then cycle through a spectrum of colors. 

I sat and screwed around with the python scripts for a bit once I hit this point. With some fairly simple changes you can do some cool stuff with the LEDS from this point. Heres a quick script I wrote to check your gmail for the subject ALARM.

 #!/usr/bin/env python  

 import RPi.GPIO as GPIO, feedparser, time  

 import thread  

 DEBUG = 1  

 SPICLK = 18  

 SPIDO = 17  

 ledpixels = [0] * 40  






 def Color(r, g, b):  

      return ((r & 0xFF) << 16) | ((g & 0xFF) << 8) | (b & 0xFF)  


 RED = Color(255, 0, 0)  

 BLUE = Color(0, 0, 255)  

 GREEN = Color(0, 255, 0)  

 ORANGE = Color(177, 53, 47)  

 OFF = Color(0, 0, 0)  

 colors = []  

 allfalse = False  

 def writestrip(pixels):  

      spidev = file("/dev/spidev0.0", "w")  

      for i in range(len(pixels)):  

           spidev.write(chr((pixels[i]>>16) & 0xFF))  

           spidev.write(chr((pixels[i]>>8) & 0xFF))  

           spidev.write(chr(pixels[i] & 0xFF))  



 def setpixelcolor(pixels, n, c):  

      if (n >= len(pixels)):  


      pixels[n] = c  

 def alert(color, delay):                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  

      for i in range(len(ledpixels)):  

           setpixelcolor(ledpixels, i, color)  



 def multiColor(colors):  

      b = 0  

      for i in range(len(ledpixels)):  

           setpixelcolor(ledpixels, i, colors[b])  



           b = b + 1  

           if(b >= len(colors)):  

                b = 0  

 def loopColors(status, colors):  

      if(status == True):  

           print("new thread")  

           for a in range(len(colors)):  

                alert(colors[a], .5)  




 class Emailees:  

      def __init__(self, email, hasEmail, color):  

  = email  

           self.hasEmail = hasEmail  

           self.color = color  

 def emailAlarmCheck(delay):  

      allmails = feedparser.parse("https://" + USERNAME + ":" + PASSWORD +"")  

      alarm = Emailees("ALARM", False, RED)  

      for i in range(len(allmails.entries)):  

           if(allmails.entries[i].title ==  

                alarm.hasEmail = True  


                print("Found ALARM")  

      allfalse = [alarm.hasEmail]  

      loopColors(allfalse, colors)  



 while True:  



Congratulations! If you made it this far you're only one step away from playing your movies with dynamic LEDS. My next and final part will cover Boblight, XBMC addons, Adalight, and attaching your lights to some sort of structure.

Monday, February 4, 2013

RaspberryPi, Boblight, and the WS2801 LED

raspberry pi ws2801 breadboard configuration taken in the midst of testing a bunch of things. it's a lot more cleaned up now.

A couple months ago I was looking for a project to start for my new Raspberry Pi. As soon as I saw the video after the jump I knew what had to be done.

Backlights! for your TV. This experience is only offered on some pricey high end phillips tvs that don't seem to be available in America., it's also available to us tinkerers for less than $125.

I'm currently on Windows 8, so if you're running Linux or Mac you'll need to substitute certain programs out like PuTTY for SSH.



  • WS2801 LED Strand (50pc) or more
  • 5-Port Switch
  • 5v 3amp(min) DC Power Supply
  • 4Gb Class 10 SD Card
  • Raspberry Pi
  • Breadboard
  • Male to Female .1" 2.43'mm Jumper Cables 
  • Wire Cutters
  • Electrical Tape
  • Zip Ties
  • Multimeter 
  • (optional) 5v MicroUSB Power
  • (optional) HDMI to VGA adapter

Download the latest image of Occidentalis and install it onto our Raspberry Pi. This OS doesn't necessarily need to be used but it will make things easier. With this image the Pi can be powered on by the GPIO pins, which will be required later, it also contains some of the packages required by boblight to communicate with those pins.

Connect the Ethernet Cable, SD Card, and lastly the MicroUSB power to the Pi.
If the OS was installed correctly this should start the boot process.

NOTE: This is a headless OS. Meaning there is no GUI by default. Our intention is to turn the machine on and "use it" over the network from your main PC. There will be no monitors or TVs attached to the raspberry pi driving the lights. 

Once Occidentalis is installed we'll need to SSH into the Pi and configure it. (Assuming you're connected to the network via ethernet)

This can be done fairly easily if you have a keyboard connected to the Pi log in with the default login. Otherwise I will usually logon to my router to check connected devices.

User: pi
Password: raspberry


you'll notice inet addr:
this is your Pi's IP Address.

If we open up PuTTY we'll be able to connect to the address above.

I've made it a habit to immediately run updates/upgrades

sudo apt-get install update
sudo apt-get install upgrade

Our next step is installing the adafruit Raspberry Pi WebIDE
paste the following command:

curl | sudo sh

Go grab a beer and wait for the install script to finish.

Once completed you'll be able to access http://raspberrypi.local and your Raspberry Pi is now fully prepared to program LEDS from a browser!

In Part 2 we'll talk about power distribution, light painting, breadboards, and we'll connect those LEDS!