design and construction up to this point

So firstly, to catch up on how this project started, and progress so far.

This was my first pedalboard, which the current project will replace:

I built it several years ago, when I was first toying with the idea of playing bass on the pedals, while playing guitar with my hands.  As you can see, the range ("compass") was limited, 1 octave (13 notes), and worse still, the spacing of the notes is not the same as any standard organ pedalboard.  Initially, I planned to overcome the limited compass using octave-switching, and also by pre-programming the notes needed for a given song and mapping them onto the keys, not necessarily the same note as the usual note-name of the key.  Also, I was going to make the keys double-up as inputs for the user interface.  A lot of UI-cleverness; but ultimately I decided I didn't want the keys to operate that way (instead, my UI is now just three buttons, replicated on all the keyboards and the pedalboard: down, up, and select).  I could make my old pedalboard work in a rock-band situation, mostly just playing the fundamental notes of chords, but for playing (or composing) baroque-style music or really anything at all mildly complicated, more was needed.  Plus, if I'm going to master the trick of playing a line of the music with my feet while also keeping both hands busy, I want to do it on the "official" organ pedal-spacing.

To find that spacing value, BTW, I had to send money to the AGO (American Guild of Organists).  No comment as to whether I also had to pass any secret-society ritual tests, to enter into the hallowed hall of knowledge of the Guild.  But I did come out with the golden information: the natural-key spacing should be 2.5 inches.  This is the only aspect of the AGO standard which I'm following.  My sharp and natural lengths are slightly shorter, travel and force will probably differ, and most significantly, I'm building this as a flat pedalboard, and not as a "concave-radiating" type as specified by the AGO.  Also, my layout is different from most (pipe) organ pedalboards in that the pedals are hinged at the back, not from a point at the front, underneath the "organ bench".  This is because I want to be able to operate these pedals both from sitting down and standing up positions.  In fact, exactly what type of "bench" or chair will work for the new kind of music I want to play, I'm not yet sure; possibly a "drum stool".

Anyway, here's a view of the old pedalboard from behind, showing the switch mechanisms.

I'm using those type of switches again in the new pedalboard, but the springs and other details will be different.  Here's my little stash of cannibalized switches, desoldered from an old computer keyboard, waiting for that phase of the construction project:

These switches have excellent repetition specs, among other assets (the other main one being cheapness, of course!).  Unfortunately, most modern computer keyboards are constructed in a one-piece manner such that you cannot separate individual keyswitches.  I covet my old 386-era PC keyboard with the keyswitches soldered to a board; it has gradually given up most of its switches but still has a few to go...

I searched around for a while, looking at different ways to do the springs.  I was originally planning to use strorebought coiled extension springs such as I used in the old pedalboard; but I wasn't immediately able to find a source for 32 of them (I guess I cleaned out my local True Value hardware store last time, and they haven't replenished!).  Plus, the rather heavy and long keylevers would probably need more spring force than I could obtain with those, from the best available leverage-point.  Items which cost anywhere near a dollar each, or more, are right out of consideration for this: a few of those, replicated 32 or 64 times, and the cost is quickly into the hundreds, which is right where I don't want it to go.  And plus, use of extension springs tends to lead to a higher profile, since the springs extend above the keys.  Given that I want this pedalboard to fold up and be as compact as possible while still being playable as a "real" pedalboard, any extension of height over the minimum implied by the height of the sharp-tops, would be nice to avoid.

So I was pleased to chance upon this idea, which I think will work: Home Depot sells these bundles of straight steel wire, galvanized, 12 guage.  They are intended for chain-link fencing, the segments of bent wire which hold the fence against the poles.  50 six-foot pieces, for under $20:

From this material, I will be able to fabricate my own coil-springs, with scissor-style action:

...which I think will have just about exactly the right amount of force, from the given position.  Which is now underneath the keys, more similar to other pedalboard designs I've seen.



I made a "video" (really, just a slide-show with voice-over), documenting construction up to this point.  Basically, all I have is the rough shapes of the keylevers, naturals and sharps, unfinished.  The hinge mechanism (and lazy assembly technique) I designed will, I think, ultimately work; but my first attempt to build it has not worked out, so everything has to be torn down and different wood used.  Typical trial-and-error for projects like this; my big effort has been to design the overall process so that the expected errors and failed experiments do not end up, say, eating up 80 feet of lumber.

Sorry about the terrible audio quality, the original recording was pretty noisy and under-modulated anyway (even with normalizing in "audacity"), but goodness, the MP4 conversion really distorts the sound even worse.  I've noticed before, this type of sketchy, noisy input tends to fare really poorly with the "MP*" family of compression.  Maybe I could have specified a higher bitrate or something.

Here I will document my current project, construction of a 32-note pedalboard for use with digital pipe organ.  Several of my musical instrument designs are intended to, someday, be produced and sold on a small scale, but this is not one of those.  I simply need a pedalboard for my own musical efforts -- and I don't want to pay a lot for it!  So this project is all about how to get something which functions adequately, at the lowest possible cost for materials, and with a minimum of fancy tools.  My one big tool investment has been a drill press; everything else is done with hand tools and a portable jigsaw.

Here is what it's looking like so far.  This gives an idea of the final layout and size (pretty big and ungainly, but I've designed it to fold in half, which will help some, and I may even make the two halves completely separable, so that I can travel with just the lower 17 notes when I don't need the full range).  However, it all needs to be ripped apart again, because the glue joints on the pivot rail did not work out: wood too dense, not enough glue penetration (even with holes which I drilled, anticipating this possible problem).  No harm done, just thought I'd try it with some wood that I had on-hand.  Now I need to obtain some softer lumber.

The keylevers are one of my serendipitous finds from Home Depot, pre-finished 8-foot 1x3s for slightly over $1 each.  I will probably end up re-finishing these levers differently, resulting in extra work to strip the existing finish (at least on the tops of the sharps), but still, the smoothness and accuracy of the shape of the boards was much better than the typical unfinished 1x3s in a similar price range.

The electronic part of this pedalboard will be extremely simple: the 32 switches (I'm using keyswitches cannibalized from an old computer keyboard) are just wired in a matrix with a diode-per-switch, and the rows and columns are brought out to a D-25 connector.  All the active electronics are housed in a different unit, which I've already built and which I use to connect my manual keyboards, wired the same way.  Currently, my interface circuit converts from these D-25 inputs, to a PC parallel port; but this is getting more and more inconvenient as no modern PCs have parallel ports any more, so I'm investigating various ways to switch over to USB instead.  One "obvious" solution are these parallel port to USB converter dongles, but given the non-standard way that I use the parallel port lines, I have not succeeded yet in getting the system to work with any of these.  A possibly better alternative would be to use a microcontroller such as Atmel AVR, and the FTDI FT232R chip, available mounted on a board for like $15.  In any case, once the switch-closure information is transferred to the PC "somehow", I have written a C program which converts that to a MIDI data stream, which can be used by software synths such as Fluidsynth.  (This is all running under Linux.)  I call my keyboard interface circuit and program, collectively, "solder2midi"; I've written about it sporadically over the past couple years, over at satanbane.xanga.com.