Turning a mouse house into a musical marvel.

by Ramon Yvarra

I’ve never considered myself particularly musical. I flirted with a few instruments over the years but was never really able to coax my body into performing the complex and repetitive motions in proper time. But I was always enamored by classical music, and piano in particular. My grandmother used to play her old upright for me when I was young, and I still remember those songs that brought a smile to my face. Every time I find myself near a piano I’ve wished that I’d learned earlier on how to play one, so that at that moment I could play something fun for those around me.

So it was one day when I found myself in an antique store just idly browsing the shelves, that I was intrigued by a stack of old QRS piano rolls. In today’s age when our digital devices hold thousands of songs, this physical piece of paper was how people over 100 years ago reproduced music on a massive scale. The format pre-dates all our magnetic formats and even computer punch-cards.

I wondered if anyone had ever gone about trying to scan a piano roll to replicate them in MIDI format. I had a few vague ideas of how to accomplish such a thing, so I bought a roll for a mere $2 and brought it home. I started researching various ways of detecting light or perforations in the paper, before I stumbled on examples of other people’s work with roll scanning.

Warren Trachtman’s work showed that there was a vast array of existing files already out there, so only slightly deterred I started thinking about taking the next step of actually converting a player piano into a full MIDI instrument, with the ability to read key presses and accept MIDI input. Again I was met with examples of work by others to do just such a thing, which honestly gave me hope that I could at the very least achieve my goal of replicating that work.

I really liked the idea behind Stanley, so I tried to reach the creators to see what kind of hardware they used to build it, but was dismissed by their public relations contact, claiming that Stanley was all “proprietary intellectual property”. This seemingly boilerplate response turned out to be only partially true, as I soon discovered that Stanley’s main hardware was a conversion kit called a “VirtualRoll”, that was a readily available solution from the Hunt Piano Company.

VirtualRoll valve boards and controller board.

After some discussion with the folks there I was told the VirtualRoll ran about $2300 for the basic system (before shipping and handling of course), and at the time I considered $2300 to be above my budget for the entire project, so I started exploring ideas behind replicating that functionality from scratch. The VirtualRoll seemed pretty simplistic in its design, and its MIDI input was only an analog DIN-4, which would have required that I interface it with a MIDI-USB converter before even being able to output information to it. I was confident that I could build something better, for less. But first I needed a piano.

The Piano

Battered but not broken

Player pianos in good condition can be found anywhere from FREE to thousands of dollars on Craigslist, and after scouring the “For Sale” pages for months I finally found a piano in my area that was in my price range. So in February 2014, $300 bought me a ‘Hobart M. Cable’ player piano from the 1920s from a seller in Campbell. The seller had been keeping it in his music studio for years, but had never fully explored trying to make it work, and he was glad to part with it and skeptical of what I planned to do with it. After $200 for shipping it arrived dirty, dusty, and with a very distinctly mousey smell about it.

Using that first roll I purchased in the antique store, and with no operating manual to speak of I was able to get the piano working using the built-in foot pedals.

A player piano works using vacuum pressure, and a series of bellows connected to hammers that hit each key.

The paper roll passes over the tracker bar connected to those bellows, and with each hole in the roll it allows the vacuum pressure through, to close the bellow and thus the hammer hits the key. Since I didn’t much want to have to sit in front of the piano for it to play, I first found myself an affordable vacuum pump.

Another $300 later and I was able to do a full test of the existing player mechanism.

Now that I was sure that the piano was in suitable working order I could focus on cleaning and doing more to understand how I could replicate the paper feeding mechanism. Again, having no manual to tell me which screws to remove, and what was safe to fiddle with I carefully removed each part and documented where each set of screws went. There was a very thick layer of dust, mouse droppings, and even glass on things. This piano had seen better days.