Jezra.net: Tubular Music Thingy Part 2

2014-12-25

Not too long about I built a tubular music thingy, and while it is nice and fun to play, I really wanted to automate the playing of some tunes as well as giving myself the ability to play certain tunes at certain times.

To be fair, this was the plan all along and I'm calling this thing "Spiel", which I guess is short for glockenspiel.

Before the tubular music thingy was built, I came up with a fairly plain-text music notation format that I call SMN: the Spiel Music Notation format. In a nutshell, SMN files start with "tNUMBER" where NUMBER is the number of beats per second, and then there will be a series of notes: G a b c d e f g, and rests: r. Both notes are rests will be considered whole notes unless followed by a number.

For example, Sudo Modprobe in SMN would be:

t30   
a4 G8 a4 G8 a8   
b8 c2 e4 d2 r8  
e4 d8 c8 d8 c8  
d8 c8 b8 a4 G8  
a4 G8 a8 b8  
c2-8 b8 G1-2

On To the Build

For the automation, I used the following:

BeagleBone Black - for running the code, network access, etc
8 12V 1A solenoids with a 10mm stroke - for striking the tubular bells
12V 6A power adapter - for powering the solonoids
8 channel 5V Relay - for sending power to individual solonoids
Cheapo USB wireless adapter

Stand Offs

What are these things called? I don't know.

What I do know, is that once the spiky bits are bent down, these things make amazing stand offs for just about any computer build.

Mount the computer and relay board

After the stand offs were put on the Beaglebone Black and the 8 channel relay, the stand offs were hot glued to the frame of the Tubular Music Thingy.

Place the solenoids

More hot glue was used to place the solenoid bell hammers.

When the solenoids are energized, they produce heat, and if they stay energized long enough, they get hot enough to melt the glue.

This led me to write a script called 'heat' that will heat up a solenoid so that I can realign the hammer for a better sound.

Wire it up!

The Beaglebone was wired to the relay (I later changed the beaglebone to relay wiring).

The relay is wired to the solenoids, and the 12V power adapter was spliced into the relay and common ground of the solenoids.

Plug it in and run some code

Here is the finished product, ready to be played, or automated over the network.

What about some code?

The code for controlling Spiel is available at https://gitorious.org/spiel/spiel The documentation is non-existent, but there are a few .smn files in the SMN directory. If you have any questions about the code, send me an email and I'll help as I can.

My last Linux Outlaws related script

The final episode of the Linux Outlaws is nearly upon us, and I needed a script that will check if the last episode has been released, and if so, trigger the Spiel device to play the Sudo Modprobe melody.

Basically, this is a Final Episode Alarm

#!/usr/bin/env python2
import urllib, time
from xml.dom.minidom import parseString
url = "http://feeds.feedburner.com/linuxoutlaws-ogg?format=xml"

#we need to loop for a while
looping = True

while looping:
  #read the URL
  f = urllib.urlopen(url)
  xml = f.read()
  #parse the XML
  obj = parseString(xml)
  #get the first item
  item = obj.getElementsByTagName("item")[0]
  #get the title
  title = item.getElementsByTagName("title")[0]
  ttext = title.firstChild.nodeValue.encode('utf8')
  #does the title contain 370?
  if "370" in ttext:
    f = open('play_smn','w')
    f.write("sudo_modprobe.smn")
    f.close()
    looping = False

  print time.strftime("%Y-%m-%d %H:%M:%S", time.localtime())
  #sleep for 5 minutes
  time.sleep(300)

So now, within 5 minutes of the final episode being released, my Spiel device will play:

Tubular Music Thingy Part 2 from jezra.net

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