Tuesday, November 8, 2016

Music & Me -- Part 5

Had a great time at the Orlando Maker Faire October 22nd and 23rd. The pipe organ proved to be very popular with several hundred people stopping by to ask about how it worked and how it was made.

 It was especially popular with the kids.

Also, I was interviewed by Caleb Kraft of Make Magazine. Here is a link to the interview.

My friend Jim, who has been helping me, and our wives came along. Here you can see the Maker of Merit award that we got.

Finally, after the interview Caleb Kraft suggested that adding LEDs to the organ indicating the note that was playing would make it more interesting to watch. I did that and here is a YouTube video showing the newly added LEDs.

Monday, October 10, 2016

Orlando Maker Faire

I will be displaying my Player Pipe Organ at the Orlando Maker Faire on October 22nd and 23rd. If you're in the area please stop by. Or, better yet, volunteer at the Maker Faire (and get in for free.)

Sunday, April 3, 2016

Music & Me Part 4 -- Version 1.0 is complete

It's finished, completed, accomplished, discharged, ended, concluded, done.

For those of you who have not been following along at home, please check out the first three installments of this project. Since my last post I finished the plumbing, again with the help of my friend Jim. You may remember from earlier posts that the wind chest has valves that control the flow of air to the organ pipes. Here you can see them with white leaf springs holding them closed. The air then needs to actually get to the pipes, which sit over the holes some of which you can see in the top of the picture.

This was accomplished using pvc plumbing pieces as shown here. The underside of the wind chest is on the left and the organ pipes sit atop the plumbing on the right.

Here is my source of air or as the organ folks say, wind. I couldn't afford a real organ blower so I went with the Shop-Vac solution. I built this box to accomplish two things. First, one could hardly hear the organ over the roar of the Shop-Vac so I needed to do something about the noise. Second, the higher the pressure in the organ the higher the pitch of the pipes. Therefore, a pressure regulator is needed to limit the changes in pressure that occur as different numbers of pipes are playing at one time. The lower box contains the Shop-Vac and muffles its noise. The upper box further muffles the noise and regulates the pressure.

Let's start with the pressure regulator first. My friend Jim used to have an HVAC (Heating, Ventilating, and Air Conditioning) business and he showed me how they regulate pressure in those systems. You can see an example on the left side of the top box. There is a door, hinged at the top. Sticking out of the door is a rod, and on the rod is a weight. When the system is running, most of the time it produces more air than the organ needs. The excess air shoves the door open and escapes. If the pressure starts to drop, as it does when more pipes are playing, the lower pressure can't hold the door open as much so the door closes a little and that boosts the pressure. The pressure can be regulated by sliding the weight in or out on the rod.

Now for the sound deadening. Here is a picture of the upper box (left) and one of the lower box (right) with their tops removed. The air inlet is on the left side of the upper box, near the top of the picture. I have sound deadening insulation near the opening because I found that there was some noise from the airflow, and some from the Vac, and insulation near the opening seemed to quiet it. The air is drawn into the hole on the left near the bottom of the picture, down to where the Vac is. Now looking at the picture of the lower box the opening from the upper box opens into the large compartment where the Vac is. The discharge from the Vac goes through the short white tube into the small compartment on the upper left of the picture. It then passes through an opening into the small compartment on the upper right. From there it flows back up into the upper box through the hole you can see in the upper right of the left picture. This compartment has the pressure regulating weighted door. The air that doesn't escape through the pressure regulator flows through the round hole through a hose to the organ. All those twists and turns, with insulation at strategic points cause the sound to be dramatically reduced, from about 90dB to about 73dB.

After getting the organ working, Jim and I went through endless sessions of tuning the forty-two pipes. We used an app called Pano Tuner, a screen shot of which is shown here. The app worked beautifully, the organ somewhat less so. After much trial and error we learned that the pipes were so close together that their sound was impacted by the pipes around them. Also, at first we were playing around with the pressure and every time we changed it we had to re-tune all the pipes. Even after we chose a final setting for that, though, we would tune the organ in the morning and when we came back in the afternoon the pipes would all be sharp or flat. We figured it may have to do with temperature and humidity. I live in Florida and the organ is in my garage so those parameters can vary quite a bit but I haven't brought it indoors yet to test that theory.

And that's it. Here are me (on the right) and Jim relieved that version 1.0 is complete. Now, those of you who have stuck with me this far get either a reward or punishment depending on your perspective. Here is a link to a YouTube video of the organ in action. Thanks for reading my blog.

And thanks once again to Matthias Wandel at woodgears.ca and Raphi Giangiulio at rwgiangiulio.com. I stand on the shoulders of giants.

Wednesday, January 27, 2016

Music and Me Part 3

Around two years ago I wrote about building a pipe organ in a post called Music and me continued. At the end of that post I said that the number of solenoids that I would need would cost quite a bit of money and I wasn't sure when I would get back to it (i.e. I am too cheap to spend that kind of money on the project.)

Well, my friend Jim from across the street came over just before Christmas and I was showing him the pipes that I had made and he asked what the next step was in the project. I said that solenoids were too expensive to take it any further and by way of illustration I called up the Electronic Goldmine website (http://www.goldmine-elec-products.com/) and what to my wondering eyes did appear but solenoids on sale for $5 each. I quickly penned a letter to Santa and there, under the tree on Christmas morning were 42 solenoids. I was back in motion once again.

Jim and I spent hours working on designs for the configuration for the solenoids and eventually hit on something that we thought would work, and here it is in the flesh.
In the lower part of the picture is the "wind chest" that I mentioned in my last post on this topic. This is a design that I pretty much just stole from Matthias Wandel from his woodgears.ca website. For springs I used hacksaw blades because they are made of spring steel. You can see that there are two rows of valves with the (mostly) white hacksaw blades pressing them down (closed). Above the wind chest you can see that there are two aluminum angles, the bottom one is populated with solenoids, the top one not yet.

Running down from the solenoids you might be able to spot thin wires attached to the valves. When the solenoid is powered it pulls on the wire and opens the valve.

So far so good. How do I play music? I mentioned in an earlier post that I planned to use MIDI (Musical Instrument Digital Interface). This is a standard that is more than 30 years old. It is used to control digital musical instruments like synthesizers, to manage stage lighting and pyrotechnics that are coordinated with music and so on. There are many thousands of songs in MIDI format available for free online. These are not sound files, though. They are instructions on what notes to play, when, for how long, and at what volume. Here is an example of some lines from a MIDI file converted to text.

   4: 1:  0  |On Note | chan= 3   | pitch=C#2 | vol=66
   |On Note | chan= 3   | pitch=C#1 | vol=64
24 |On Note | chan= 3   | pitch=F#2 | vol=52
43 |(Off) Note  | chan= 3   | pitch=f#2
48 |On Note | chan= 3   | pitch=G#2 | vol=56
61 |(Off) Note  | chan= 3   | pitch=g#2
72 |On Note | chan= 3   | pitch=E 3 | vol=88
   |On Note | chan= 3   | pitch=B 2 | vol=76
   |On Note | chan= 3   | pitch=F#2 | vol=76
   |On Note | chan= 3   | pitch=G#2 | vol=68
90 |(Off) Note  | chan= 3   | pitch=g#2
91 |(Off) Note  | chan= 3   | pitch=b 2
94 |(Off) Note  | chan= 3   | pitch=c#2
95 |(Off) Note  | chan= 3   | pitch=e 3
   |(Off) Note  | chan= 3   | pitch=f#2
      2:  8 |(Off) Note  | chan= 3   | pitch=c#1

The numbers on the left are timing. Then comes the instruction. The channel is the instrument, then the note, and finally the volume. This particular MIDI file breaks each beat into 96 increments. So, for instance, the first line says "at the beginning of the first beat of the fourth measure, for instrument number 3, start playing C# in the second octave at a volume of 66". The next line says "at the same time start playing C# in the first octave". Then after 24/96ths of a beat (or actually 25/96ths of a beat because the counting starts at 0 rather than 1) start playing F# in the second octave. Then 19/96ths (43-24=19) of a beat later turn of F# in the second octave. And so on, and so on.

I had an Arduino Due microcontroller and hooked up an SD card reader to it and put a MIDI file on the SD card.

Here is the Arduino. It has 53 output pins. Under program control it can turn each of these on or off. I wrote a program on the Arduino that assigns each note to a pin. Then it reads the file and turns the pins on and off with the correct timing. Since I only have 42 notes on the organ I only need 42 pins. These pins can only supply a tiny amount of electricity, however, not nearly enough to trigger a solenoid.

My sister Monica and her husband Jim happened to be visiting, and she and he and I built this board.
The main components are 42 transistors. These work like electronic switches. The tiny amount of electricity from the Arduino can turn on a transistor, and a transistor can switch enough electricity to trigger a solenoid.

I still have to wire all this stuff together but I'm pretty confident that it will work

And what about all those pipes, you might ask. Not tons of progress on that front, with one exception. Again, I have been using the information provided by Raphi Giangiulio's YouTube videos on how to make wooden organ pipes.

In looking at his specifications there was something that didn't make sense to me. As the pitch gets lower the pipes get bigger until we get below C below middle C. Then they are significantly smaller. I didn't understand that so I sent an email to Raphi and he generously responded and explained that Bourdan pipes are stoppered. That means there is an airtight stopper put into the pipe and that lowers the frequency. It's counter-intuitive but it works. Here are a series of five pipes in order of frequency with the lowest on the left.

And here is a shot of a couple of stoppers.

I have only 18 pipes of the 42 pipes made, and so I am not nearly finished with the project but I am re-invigorated. I'll keep you up-to-date.