Thursday, September 17, 2015

Organ Donor Successfully Completes Deployment at Burning Man

Organ Donor successfully completed a deployment at Burning Man 2015 as part of Sol Diego's Wonderlust Arcade installation. The five-day deployment was located with 28 other regional projects under tents at the base of The Man. The Midway was open 24 hours a day from event start until 5pm Friday before the burn.

The Wonderlust Midway installation included a forced perspective building and a variety of arcade and midway games and a Zoltar booth. Games were designed and built by members of the Sol Diego team. An article about the forced perspective construction and the games can be found at:

http://www.sdcitybeat.com/sandiego/article-14497-sol-diego-brings-immersive-art-to-burning-man.html

Setup took Organ Donors Paul and Abraxas about 8 hours over two days to complete, including ferrying components and tools out to the Midway (with a 5 mph speed limit). Conditions were windy and dusty, with visibility falling to zero at times. Organ Donor setup had to work with and around all the other teams setting up their art installations.

Substantial changes to the console and software were made from the previous deployment. A new console design was introduced. The minimum desired software functionality was completed on the second day, about an hour before event start. More ambitious software plans, including touchscreen support and graphical user interface features, would have to wait for a later deployment.

The new organ console (version 2.0) improved stability and function. Sturdy legs from IKEA, a cut down IKEA tabletop, and a custom laser-cut cabinet were key elements of the new console, replacing the lightweight folding stage stand and small custom control panel. The console would no longer tip over (or blow away!) as easily, and had improved aesthetics. The two manuals (that is, organ keyboards) and MIDI combiner and coupler management software were carried over from version 1.0 of the console. Version 2.0 added a sheet music stand, an LCD touch-screen, a selector knob, and a laser-engraved diagram to label and explain the stops and coupler buttons. The touch-screen and selector knob were managed by a Raspberry Pi 2 with software written in Python, and the active coupler diagram was managed by an Arduino MEGA 2560.

No substantial changes were made to the pipes, racks, windchest, or blower box. A minor rearrangement of the pipe positions around the rack was necessary to accommodate the shape of the limited space available.

The first failure was with the windchest, which is made of laser-cut acrylic. The front bottom left edge of the windchest leaked during the first pressurization. While the proper solvent-based acrylic cement could be purchased from Reno, that would involve a lengthy trip. Fortunately, Organ Donor Bigun had acrylic cement in his kit. We borrowed a tube, applied the cement, and clamped the windchest closed. This seam held for the duration of the event, possibly because we left the clamps in place. Organ Donor Bigun recommended the addition of a square acrylic rod glued along the seam on the inside of the windchest as a reinforcement. Since the seam is somewhat long, this reinforcement would reduce the amount of flex that probably caused the seam to pop.

The second failure was of both keyboards. When tested after a few hours of dust storm during setup, about half the keys on both manuals were no longer working. We suspected dust fouling the contacts inside the keyboard. With the dust storm continuing and worsening, the keyboards were removed and taken back to Copper Home, Organ Donor's support trailer at Wonderlust Camp. The keyboards were disassembled and inspected. Each key has a series of blue rubber boots that provide domes for each key to press down upon. A contact beneath each dome is actuated when the dome is compressed. Dust had worked its way beneath the rubber boots. The factory design looked more than adequate for normal conditions, but wasn't up to being inundated with playa dust.

A repair was proposed. We would thoroughly clean the contacts and the rubber boots, then use silicone sealant to completely seal the dust boots to the circuit board. The rest of the interior of the keyboard would be allowed to collect dust. Since the rest of the keyboard consisted of mechanical action and the components on the circuit board, confidence was high that the repair would work.

Both dusty keyboards, and the clean pair of backup keyboards, were treated with silicone sealant. In order to replace the dust boots, tool improvisation was required. The rubber plugs that anchor the dust boots would not fit back into the holes by finger pressure. Very small holes were observed at the top of each of the rubber plugs/feet. An unwound paper clip worked perfectly to refit the rubber anchor feet. The strip of dust boots was placed in the correct position, then the paper clip gently pressed into the hole over the top of each plug/foot. The foot then slipped into the hole with no difficulty.

Photos can be found here:

https://www.flickr.com/photos/w5nyv/albums/72157658511444682

After the keyboards were treated with sealant, they were returned to the console in the Midway. On the final day, one of the repaired keyboards failed, with just two keys no longer responding to key presses. This was swapped out for one of the backup keyboards. This keyboard worked the rest of the day until close of Midway. The other repaired keyboard lasted the entire event without failures. Later examination showed that we left gaps in the silicone sealant at each of the places where keys failed.

Software functionality for the Midway exhibit consisted of two modes, keyboard and jukebox. Jukebox mode was where Organ Donor played files from the songs directory in the Raspberry Pi. Keyboard mode was where the participant played the keyboard. Participants could play the keyboard at any time, but keyboard mode turned off any MIDI signals being sent to the windchest from the Raspberry Pi.

The Organ Donor received overwhelmingly positive feedback. Conservatory students, amateur musicians, and people that don't have any experience playing a keyboard all were encouraged to play Organ Donor.

One participant, Anthony Decognito, made up songs extemporaneously about other participants. He inquired as to their city of origin, made up a melody, and improvised a song. This was hugely successful.

Several pop-up concerts were held by people that happened to have large amounts of music memorized. The team greatly appreciated the willingness of so many participants that freely shared their talents and training. Crowds gathered in waves to listen and play.

The jukebox mode was freely used. While several lost and found items were recovered, no obvious abuse occurred. While at least one participant used a very unconventional body part to play the keyboard, Organ Donor was unscathed by heavy participant use.

Complete set of photos from the deployment can be found here https://www.flickr.com/photos/w5nyv/albums/72157656113224673

We found that most people didn't really study the coupler diagram, and were generally unwilling to read the verbose text-mode displays on the LCD to understand how to switch between keyboard and jukebox modes. This wasn't entirely surprising, but it did spark some discussion and decisions on how to improve the console for version 3.0.

With some strategic text placement, the coupler diagram could perhaps be improved to the point of not requiring a lot of explanation. During exhibition, it did not take much additional explanation to make the coupler diagram come alive, but the fact that it did take some additional explanation at all means there is room for improvement in this particular interface. Plans are in place to improve this particular interface for San Diego Maker Faire (3-4 October 2015).

For the LCD screen that showed status and gave instructions for jukebox vs. keyboard mode, it was felt that a big image on the screen and callouts on the knob would improve ease of operation.

Upon return to San Diego, the blower box, windchest, and pipes were cleaned with compressed air and damp cloths, and Organ Donor was set up for San Diego Maker Faire improvements.


Anyone interested in the project is welcome to follow along and is invited to consider becoming an Organ Donor. The project needs skills of all types, including machine learning, coding, user interface design, game theory, carpentry, laser cutting, 2D and 3D modeling, 3D printing, and many other areas. Contact Abraxas or Paul by sending a message through this site.

Saturday, August 15, 2015

Kickstarter that helps Organ Donor

Do you like Organ Donor?

Did you know that Organ Donor will be at Burning Man this year?

Did you know that you can help?

This project is hosting our machine learning pipe organ. If you donate to it, you are helping Organ Donor. 

Please consider donating. Leave a note in the comments that you're an Organ Donor supporter. *Any* amount helps. 

https://www.kickstarter.com/projects/soldiego/wonderlust-arcades-trip-to-burning-man?ref=card

Thursday, June 18, 2015

High Tech High Meetup Playlist

Organ Donor is going to be presented at the Maker Faire meetup at High Tech High on 20 June. Here's the playlist for our 5 minute window :+)





Tuesday, June 16, 2015

Digging Into Questions About Entropy

Here's a graph that represents two things. First, a lot of work completed. Second, a lot of work that needs to be done!

These three curves are the bits of entropy per sliding window location in a work by Buxtehude (Prelude and Fugue in G Minor). The width of the window is set by the Kemeny constant of the MIDI track. There are three tracks: Swell, Great, and Pedal. 
On a pipe organ, the main manual (keyboard) is called the Great. It is usually the bottom manual on two-manual instruments, or the middle manual on three-manual instruments. The upper manual is called the Swell. The Pedal is usually the very lowest notes in the piece. This is often played with the feet on the pedalboard. 
Each of these tracks represents the music that would be played on the corresponding part of the instrument. Each part can be voiced on a completely separate rank of pipes, creating a layered sound. 
In the MIDI version, each of the tracks is examined mathematically. First, a Markov chain is derived. This is a table that shows how likely it is for any particular note to follow a particular note. Starting with the first note and going all the way to the end, all combinations of the notes that follow the previous note are recorded, and then the probabilities calculated.
Next, the Kemeny Constant is found. This is the number of steps from a starting note to a randomly selected note chosen from the Markov chain's stationary distribution. No matter which starting note is selected from the piece, it takes about the same amount of steps to reach the randomly selected note from the piece. This number of steps is the width of our sliding window. The window function slides over the track. For each window, the entropy of the windowed sample is measured.
What we're looking for is places where the entropy changes dramatically. This would potentially indicate a local change in the entropy of the piece, which may indicate a compositional change or transition in the work. Identifying macro-phrases like this may be helpful in constructing algorithmic compositions that better emulate human composition. 
As you can tell from the graph, the tracks do not line up. The pedal track is much shorter than the great, which is shorter than the swell. Therefore, the number of windows evaluated is not the same across the three tracks. This means that the samples are not aligned in time if they are simply listed along the horizontal axis. The samples need to be normalized for observed time. This (using the timestamps in the MIDI file to align the samples) is the next task in the design of this part of the software. 

Sunday, June 7, 2015

Organ Donor at San Diego County Fair - Day 2

We spent part of the day demonstrating and maintaining Organ Donor Opus 1 at the San Diego County Fair today.

We arrived to find a blown fuse! We replaced it and got Opus 1 back up and running at full capacity. The blown fuse took out one of the two controllers, so only half the pipes were playing. However, with all the settings usually selected, plenty of notes were filling in the sound.

We measured the console to make Version Two, which will include updated controls and a screen. The screen-equipped console is dubbed The Organelle. We're 3D printing the escutcheon and backplate for the screen over the next few days.

We disinfected the keys with clorox wipes and checked to make sure all the tubing was still in place.

More Fair next week! The Fair is closed Monday and Tuesday, but opens back up on Wednesday.

People love the organ, enjoy playing it, and some are actually studying the posters. See the Documents page for the current set of posters!


Thursday, June 4, 2015

Check out our pipe construction poster that we made for our exhibit at the 2015 San Diego County Fair!

http://www.sol-diego.org/Documents/OrganDonorPipeConstructionPoster.pdf