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Photo by Piotr Wojnarski

The Continuing Adventures of Amelia Mouse

Ramon
Ramon
Sep 11, 2016 · 15 min read

Shows, upgrades, and travel.
by Ramon Yvarra

There’s nothing like the success of a project to get you more excited to show it around, and continue adding to it. Starting with my previous article. Thanks to some reposts on Medium and on blogs such as ‘Hack a Day’ (Making a Player Piano Talk MIDI) my original article gained about 25,000 views, within days. I was contacted by several excited individuals about the project and even managed to inspire some of them to continue their own piano conversion projects. It was clear that Amelia was a hit with music lovers and tinkerers the world over. It was because of that excitement that I decided to continue to make Amelia a piece I could configure and add to other events. The 2014 performance at FIGMENT was just the beginning of Amelia’s shows and since then there’ve been many improvements.

The Fallen Cosmos — 1/2015

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The Garden of Earthly Delights

Amelia performed in a corner on the ‘Earthly plane’, playing music composed by UNW♀MⒶN, and running visualizations I created that were appropriate for the show. The 15 minutes piece played variations of notes that were found on the butt of one of the characters in the hellscape panel of the painting.

For the 45 minutes of the show Amelia repeated this tune, snaring in people as they wandered between the amazing art, sculptures, performances, and experiences. It was a truly magical show.

Maker Faire San Mateo — 5/2015

To make it easy to point people to my previous Medium article I printed out about 500 postcards with a URL and my info on it, along with some shots from the build. Each card had this small poem on it:

Amelia mouse lived in house, in a wall, on a farm, by a river.
Till one day, while she was away, a mysterious box was delivered.
On Amelia’s return the noises she heard were magical, wondrous and new.
It opened her mind, to tempo and rhyme, and changed her whole musical view.
She moved all her things, her cheeses and strings, and sang cheerful songs in soprano. For now she could play, every night, every day, in her home that was called a piano.

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I learned a lot about people during that show, and realized that playing the keys and seeing the visualization was such a natural expectation that when people played and didn’t see the change, they were momentarily disappointed. I vowed to finish my original work and make Amelia fully interactive before the next show. I also learned that without a more robust wheel system I wasn’t able to move Amelia around very easily. The dollys that I’d created were suitable for staying on the ground, but moving it on and off of a trailer was a serious exercise and damaged the 90 year old case of the piano every time we lifted and banged it. Despite all the headaches of getting it there, at the end of the week I was awarded an Editor’s Choice ribbon by one of the editors of Make Magazine.

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It’s just a ribbon, but it’s nice to feel appreciated. :)

The Next Phase — Key Scanning

I cobbled together a quick test circuit, and wrote some code to detect the speed of the keypresses and translate that to a velocity number for the MIDI note. Following the success of the solenoid tests I knew that if I could get this working once, I could replicate it across all 88 keys.

Now that I had a good test going, I needed to secure a lot more phototransistors that were going to be easy to mount inside the piano. Because the key widths varied I didn’t want to try designing a PCB and have them not line up, so instead I was able to find a great deal on these line sensing robot boards at Pololu, which did the trick perfectly. They even came with right angle headers that would make cabling easy.

The scanner boards I designed use two 16-bit multiplexers to handle 16 sensors at a time.

The reason for the dual multiplexers is that I’m using one to handle supplying power to the IR LED, and the other to handle switching which light sensor to pass to the Arduino. This way I could have 6 boards, each sensing 16 keys at a speed that was fast enough to sense all the keys with a fast enough attack rate. One could argue that a single Arduino Mega 2560 doesn’t have the speed to track keypresses on every key at a fast attack rate, but I haven’t been disappointed yet at its output.

After some testing and prototyping I designed and ordered new boards from OSH Park. The first version I designed used surface mount components, and I learned very quickly that I didn’t have the skills or tools necessary to successfully solder tiny ICs to a board without burning the heck out of them. :( So I had to redesign the boards for through-hole components and rebuild them.

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My test harness

Each sensor gets mounted under a key, and detects the distance from the key to the sensor. By measuring the amount of time it takes for the key to go down, I can determine key velocity, for when the piano is part of a recording session, or to vary the visualization.

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Left: Keyscanner board. Top Right: Array of sensors. Bottom Right: Individual sensors.

I was running up against a deadline to get this hardware installed for the next event, which resulted in me trying to install it on-site, outdoors…that is until it started raining and I had to move everything back inside. Something that I learned the hard way, was that crimping connectors can be a tricky endeavor.

I was using these crimp connectors from SparkFun and had to uncrimp and re-crimp several, as the pins inside can bend very easily and thus not pierce the wiring. I wasted a lot of time on software before I broke out the multimeter and tested the cables themselves. Because of this and several other setbacks I had to revert back to standard playing. But thankfully that still worked despite the spot of rain.

Priceless — 7/2015

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The Priceless movers loading Amelia into the box truck

Priceless is an art and music festival held in the wooded mountain town of Belden, CA. Amelia was accepted as an art installation, and so with some new dollys and an untested key scanner (which ended up failing as mentioned above) she was on her way to her first music festival.

Despite the mishaps with the key scanning Amelia still thrilled many during the event, performing in the historic Belden Lodge.

Something I learned from that performance is that without constant supervision Amelia isn’t much to see. I committed to play an hour set, and then take a two hour break. But this meant that while I was away Amelia was just a normal piano. Not much to see. So I was doubly committed to getting the key scanning components working when I got home, and within a couple months of tinkering and fiddling I finally tracked down all the lingering hardware and software issues to make it work perfectly.

Maker Faire San Diego — 10/2015

Do you have any advice for burgeoning makers?
Don’t be afraid of failure. Every great inventor and creator failed a hundred times before they succeeded. The person that created that amazing thing was probably banging their head against the wall until they got it to work.

I’d had my travel plans all worked out, but unfortunately a series of events forced me to cancel my appearance on the day I was set to travel down to San Diego. While disappointed, this was an important lesson for me to start figuring out how to more reliably manage the logistics of moving my art.

FIGMENT — 10/2015

At this point I was feeling incredibly down. I had to cancel two appearances within a few weeks of each other, and I was just uncertain of how to address the problem of repairing / replacing the base of a 90+ year old piano that weighed roughly 700 pounds.

Piano Tilting

But I didn’t feel like spending $600 for something I might only use once, and it’s not something a piano repair place would rent out. So I had to find another solution. Based on some video I found, it looked like a wooden alternative would be sufficient.

I just had to find or design the plans for such a thing. A little more digging turned up an online distributor that sold an eBook with plans for a wooden tilter. Getting this eBook seemed incredibly complicated, as it could only be read through a proprietary PC program. Parallels to the rescue.

The plans inside were very basic, but using them I was able to put together a CAD model of the tilter, and build it with wood I mostly had on hand.

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With a couple ratchet straps and extra hands we were able to tilt Amelia with relative ease, and the tilter never once felt unstable. An inspection of the underside confirmed that the base board had cracked nearly in half, and the 90 year old screws meant to hold it together were practically falling out.

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A Sturdier Base

I wanted to make sure the base would clear the trailer hinge point, while still keeping the height of the piano as low as possible.

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Top: Angle calculations for the trailer and base. Left: Mockup of piano on base. Right: Base before holes locations were calculated.

The large 12" diameter tires gave me a good clearance, and smooth movement over most surfaces. I also discovered that by using an “axle stub” I could mount the wheels with a simple cotter pin. Between the stubs, the wheels, and mounting using an almost excessive amount of bolts, I designed a base that would stand up to future traveling, but because of time constraints I had to make the wheels fixed. This meant any turned had to be done by lifting one side and shifting it.

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My design called for drilling deep holes into the thickest places in the wood of the piano, to make it as sturdy as possible. This required long bore drill bits, almost a foot long, and while drilling the rear center hole the bit jammed into it, unable to drill deeper or reverse out. This “bit of shame” remains lodge there to this day, a constant reminder to drill slow and cautiously in the future. 😩 Luckily it is completely hidden when the piano is upright.

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Top: Amelia on her new big wheel. Left: My welder friend who went above and beyond to help me in time for Maker Faire. Right: Amelia in the trailer.

Maker Faire San Mateo — 5/2016

At first I wanted to run vertical strips of WS2812B LEDs up and down the dress, and have each strip respondent to a different note on the diatonic scale, which meant 7 strips. Finding power specs was difficult, and to be honest my familiarity with power math isn’t great, but from what I could find online I put together this spreadsheet to play with the values until I figured out how many LEDs I could reasonably power for an hour’s performance.

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Each LED’s power draw changes depending on its brightness and color. So figuring the battery requirements was mostly an “educated” guess. I landed on this one:

Eventually after some collaboration (and some honesty with the time constraints) I parred the design to be a single strip, wrapped around the wearer. Now that I had power worked out I could focus on code. Since Amelia’s code was built on the Arduino AppleMidi framework it made sense to use an Arduino compatible board as a controller for the garment to share a codebase, so I started with an ESP8266 board.

After some minor bug fixes to my code to make it compatible with the ESP, I added FastLED to the project so I could easily work up several lighting profiles.

Because MIDI has multiple non-instrument channels, and that information could be encoded by UNW♀MⒶN in her composition software, I was able to code the controller to change the lighting routine at different points in the song, as well as the colors themselves.

UNW♀MⒶN performed several sets during the event, and all the pieces worked together wonderfully.

Between the performances, the new base, garment, and the key scanner I was really happy with how Amelia worked out, and by complete surprise I was awarded another ‘Editor’s Choice’ ribbon.

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Priceless — 7/2016

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It was extremely rewarding to pass Amelia throughout the event and to see one or more people just enjoying playing and the experience.

Northern Nights — 7/2016

I was still pretty burned out from Priceless, but after a little convincing I agreed to bring Amelia to their weekend long event in Piercy California, just one week away. Having never been to Northern Nights I had no idea what to expect, and while my days were mostly filled with building more visualizations for Amelia, the nights were filled with some of the most joyous attendees. Everyone who approached Amelia became instantly enamored and watched eagerly as each new visualization cycled.

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The End of Phase 2

Thanks to everyone whose supported me in the last few years on this project, and for all the artists and curators who’ve invited me in to your events. I look forward to many more.

For all the updates on Amelia be sure to follow @mousepiano on Twitter.

-R-

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