slideshow of construction photos

http://youtu.be/QCqSQkQjr7w

first sounds...

A reprise of the two photos which together, best convey what the final result looks like:

I made a video, me playing the pedalboard (just the LHS section: this will be a common configuration for me), along with my little zither.

http://youtu.be/jK5UKCgQcJg

(Fortunately, I have found another format which seems to preserve the audio quality (such as it is, coming from the camera's built-in 8kHz mic) better than my first video in this blog.  Hopefully, even after the additional downstream youtube processing, it'll still be acoustically legible.)

wired for sound

So since the last time, I have basically brought this project to completion.  At least, enough completion that I can play music on it, which is the chief goal.  A few more details such as hinges and some touch-up painting, remain.  But now I can plug it into my solder2midi system, step on pedals, and hear sound.

First, a top view of LHS, to match the RHS view in the last post.

More pics of the springs, which is where work left off in the last post.

Now for the circuit boards.  The cannibalized computer keyswitches are mounted on Radio Shack perfboard, along with a diode in series with each switch.  Here, you can see the little clip I made to hold the switches in place while I solder them:

Here are all the boards, with switches and diodes mounted.  I arranged it so the rest of the wiring can be done from the back, with the boards mounted in the units.

I keep the plastic keycaps in place on the switches, even though they are not all of uniform shape.  They make a much easier target to hit with my simple spring actuators, which themselves can be bent to accomodate the shape of each keycap.  (More custom-bending of wires, but oh well.)

The LHS unit has two D-25 jacks, "solder2midi out" and "solder2midi thru", as it were (actually, the jacks are in complete parallel, but one is M and one is F).  These mount on plywood panels.  The RHS has a loose D-25 cable end, which plugs into the "thru" jack on LHS.

Here's wiring up LHS.  Lots of Radio Shack solid-core 4-conductor phone cable.

Here's LHS with cables wire-tied in place, and switch actuator springs being glued.  Hopefully the glue will keep the springs from working loose, now that they are screwed into place and bent to the right shapes.

Making the actuator springs for RHS.  I used 16-guage steel wire for this (as opposed to the main springs which are 12-guage).

And finally, here's RHS wired-up and plugged into LHS.  A quick test reveals all 32 notes working (and the right notes!).  Time to play with it...

I'm already planning my next musical project, a "dulce-melos" composed of my existing 15-note zither, plus a keyboard which I'll build (a test-bed for a larger dulce-melos afterwards).  But that's a different story.

fitting the pieces together

Since the last post, it's been a lot of fabricating and tinkering with the smaller pieces of wood which hold the whole thing together.  The two pedalboard units, LHS and RHS, now have their functional shapes, and can stand up on their own, or lie flat in playing position.  This is very convenient for further work; up until this point, the incomplete sets of pedals on their pivot rails have been fragile and vulnerable to sideways torques snapping off the keylevers.  Now the project starts to look almost complete.

First, the four vertical supports, which connect the guide rails to the pivot rails.  Overall, my design aesthetic here is basically to winnow everything down to the "mathematical theorem", the least amount of materials processed with the smallest amount of effort and tools, which is still able to produce a functional and playable pedalboard.  However, just like with the gold paint (and really, the decision to use any paint at all), I can't resist a few extra touches to try to make it look a little better.  Rather than straight cuts, I cut the front edges of the vertical supports in a decorative "S" shape:

The curved slots are for the inner support pieces to clear the pivot wires.  If the vertical supports had been in place first, the wires would have just passed through drilled holes.  The rectangular opening on the LHS side panel is for the D-25 jack.  There will be this one jack, for the connecting cable to my solder2midi system (the digital pipe organ).  The two pedalboard sections, LHS and RHS, will connect together with loose male and female D-25 cable ends, which tuck underneath when plugged together.  Thus, the LHS can be used standalone; and if one really wanted, the RHS could also be used standalone by plugging its cable end directly into the solder2midi system.  I still haven't scoped out the right hinge hardware, to allow the units to hinge together but also come completely apart.  Possibly, there may be no hinge: just a way to hang the two units together in a back-to-back package for carrying, and then for playing the two are just placed next to each other...  Yet To Be Decided.

The vertical supports also hold up the nameplates.

Because of my paint-it-first approach, I later have to remove paint (through sanding) in strategic areas, to enable the wood glue to take hold.  With enough foresight, these areas could have been masked with tape (as I did with the D-25 opening), but since I'm designing as I go, I can at best only hope to have enough foresight not to make big mistakes that ruin lots of material; smaller changes come with the territory.

Sheetrock-type woodscrews hold the pieces in place for the glue to take hold, and give extra strength like rebar does in concrete.

Now, time to make the foot-boards, the planks which will have rubber feet -- and which need to be the right length and in positions to support the unit properly, as pedals are pushed down.  My initial experiments showed that the foot boards needed to be quite a bit longer than I originally planned, because of the strong torque when the long keylevers are pushed down against the spring force: the whole unit tends to want to flip forward on its front feet, the back feet coming off the floor.  My design is so light (relatively) that there isn't a big clunky weight to hold things in place.  Someday, there will probably be a tower of manual keyboards mounted on top, which would hold things in place pretty well I imagine, but anyway...

With the foot-boards installed, and with temporary scrap-wood instead of the nice nameplates to keep the keylevers corralled in place, I can finally stand the units up in the vertical position, as intended for transport.  Placed back-to-back in the positions they'll be in when hinged, one can see that the four foot-boards interlace conveniently: the two belonging to the RHS are more narrowly spaced and fit in between the two wide ones of the LHS.  This is just a matter of happy coincidence, of the positions of the sharps in the 32-note pedalboard (the places where there *aren't* sharps being the obvious locations for extra structure); and of the place where I chose to make the LHS/RHS split, which really couldn't be any other place (again because of the sharps), assuming splitting into two pieces.

Doing some touch-up painting on the frame.  The ability of the keylevers to flip up and over, once the nameplate is removed, is convenient for service (especially since the keylevers are not individually removeable, as they would be in many keyboard and pedalboard designs).

Now, adding the felt to the nameplates and spring rails, which will define the upper and lower travel limits of the pedals.  I'm starting out with a rather deep amount of travel, nearly the width of the vertical support lumber minus the width of the keylever lumber (and minus the felt).  I figure, if I later want to reduce the travel when I can finally feel how it really plays, that'll be easier than trying to increase the travel: I'll have to tear out the felt on the nameplates and then add shims of wood to the nameplate undersides, and new felts.  This will lower the top (quiescent) travel position, preserving the nice, close-to-the-floor bottom travel position.  (At one time, I thought about making the travel (field-) adjustable, but nah.)

And now, time to fabricate 32 as-identical-as-possible springs, from my supply of straight 12-guage steel wire.  (Simple things like finding that cheap supply of straight wire at Home Depot, have made all the difference in this project.  None of the other spring ideas that I considered, would have had the strength to balance these long keylevers, I now see; and if the wire I'm fabricating the springs from were not initially straight (i.e., if it were pulled from a spool or coil), the effort to shape the springs would have been dramatically more tedious, with less consistent results.)

Shallow holes are bored into the bottoms of the keylevers, to receive the ends of the springs.

After passing the straight longer end of each spring through its hole in the spring rail, I bend the end over 90 degrees; this end then passes through a second hole at right-angles when the spring rail is joined to the guide rail.

Despite my best efforts to manufacture the springs consistently, it turns out that each one needs to be custom-bent after installation, in order to make the action and strength consistent and to make the coiled center of the spring stay in the right place throughout the travel.  They end up looking kinda ugly and crooked, but at least the behaviour of each one is correct.

(The issue is the exact length of the two straight legs of the spring, vis a vis the position of the coil in the middle: I could have probably attained better consistency by making the legs slightly too long, and clipping to size after forming the coils; but to try to save material and effort, I attempted to form the coils in a consistent position on the final length of wire; however, given the "angular amplification" between the small distance separating the two ends of the spring when installed, and the long length of the legs from the ends to the coil (about 6 inches), a small error in the coil position (i.e., lengths of the legs) causes a large amount of "steer", upwards or downwards, in the motion of the coil end as the pedal moves.  If the coil moves upwards, it hits the keylever, and if it moves downwards, it hits the floor, in either case causing noise and a bad feel to the action (and maybe messing up your floor!).  Another way to address this would have been to use screws-and-washers to hold down the ends of the springs, after passing through the holes in the spring-rail: this would have allowed the spring end to be moved forward and back to adjust the motion of the coil.  Of course, I had thought I was clever to eliminate the screws-and-washers...)

I'm just glad that there *is* a way to bend each spring such that it operates correctly and stays in place.  I knew this might be tricky, given the inherent difference in the lengths of the two legs the way I have designed it.  I was prepared to have to add more wood, in order to permit exactly-symmetrical springs (and I have enough steel wire on-hand to make a whole new set if it had come to that); but fortunately, it seems I can make the current arrangement work, with a certain amount of tedious effort.

Now, the basic physical structure is in-place, and the pedals are playable (with no sound).  Next up, a lot of little fittings and details such as hinges, latches, and feet; and the other major element: the electrical wiring.

Oh yes, BTW, I should discuss the phrase "LUX SIT" a little.  Happens to be the slogan on the coat of arms of one of my "alma maters", the University of Washington, though frankly I had forgotten that when I chose it for this project.  It is alleged to be a bad Latin translation of the phrase "let there be light".  A better translation of God's invocation of creation in the Book of Genesis, I'm told, would be "FIAT LUX", which means something like "let the light come into being" (where it previously had not existed).  "LUX SIT", those who have any knowledge in this area say, means something more like "let the light continue to exist".  However, this latter meaning seems closer to my intent anyway, so I keep it that way.  I'm not trying to pre-empt God here!  (It is traditional for many harpsichords and other ancient keyboard instruments to carry an inscription, usually in Latin.  Actually, if I really wanted to repeat God's phrase from Genesis, I'd probably use Hebrew characters, which also have the important benefit of looking really cool.)

lotsa painting...

Many steps of painting in the past two weeks, mostly with 24-hour delays in between for the slow-drying gloss paints to cure.

So this phase started like this, with just the pivot rail painted in flat black and the white primer still visible on the keylevers, except where they have been sanded:

My experiments with home-brewed black dye have been a complete failure so far.  But to at least make some effort towards longevity (i.e., so that the black doesn't wear through to bare wood), I soaked flat black spraypaint into the sanded tops of the sharps, with a paintbrush, before doing the gloss overcoats.

Here's trussing up the sections to paint the sharps with gloss black:

And then the naturals.  I thought something other than blazing white would be good for the naturals.  In fact, after I start to see how it all looks, I think a reversed colour scheme (dark naturals, light sharps) would probably have been better -- as opposed to manual keyboards (harpsichord, organ), where I have reluctantly conceded that, even though the reverse colour style looks so much more exciting and exotic and "non-piano", actually light naturals and dark sharps are better, from a visibility standpoint.  So, like many reverse-colour keyboards, I add some (metallic gold) highlights, which are mostly for looks, but maybe also improve visibility.

Here are the pieces of the nameplate.  It's only called the nameplate because of its functional position, by analogy with harpsichords.  And originally it was going to be mounted vertically, in such a way that the sharps would have obscured any writing.  But then I decided to go with horizontal mounting, so it will be facing straight up in playing position.  And as long as I'm at it with the gold paint, I decided to try a lettering technique I thought of, which I might use for the future clavichord and harpsichord.

First, several coats of metallic gold.

(And here again is my basement-hallway drying rack: with good airflow to the outdoors, which is quite necessary with this chemical-warfare grade gloss paint.)

Then I cover the face with clear packing tape.  I used two layers, but I think one would work as well or better, especially given the clearcoat sealing technique.  I draw the design with Sharpie; I used rough measurements to space the letters correctly, but the outlines are freehand because I want a slightly disheveled and individualistic look.  This technique would also be amenable to outlines produced on laser printer.

For a good several hours, I labouriously went around the outline of each character with this sharp little screwdriver, using it as a punch to poke through the plastic tape and indent the wood.  Not only did this tend to seal the edges of the tape a little better against the coming deluge of paint (but this wouldn't have been enough), it also made a very nice looking mark in the wood in its own right.  I figured, even if my fancy tape-masking procedures came to nought, I could just paint it solid black and then fill in the letters by hand with gold paint, using a small brush.  Getting the tape to remain in place over sharp acute angles required some learned finesse: approach the corner from each side, leaving the very tip connected until last (or else cutting the second side pulls the plastic off-center from the already-cut first side, like a cover-thief in bed).

Peel away tape from the negative space regions, leaving only letters covered.

Here's the finished design, letters covered with tape.

The key step, my bright idea to make this technique actually work, is to seal the taped letters with a coat of clearcoat, before the black.  Probably gold paint would have worked for this step, too.  The idea is to prevent the black paint from wicking under the edges of the tape, especially on all the delicate sharp corners.

Then (24 hours later), black gloss, a couple coats.

Then, ta-da!  The experiment worked, the paint didn't dissolve the tape or whatnot, with some care it is not too hard to peel it off.

Then, another layer of clearcoat to seal everything.

I'm glad I managed to schedule a lot of this painting while it's been sunny and dry in Seattle.  This week, it's going to be rainy again, they're saying.  After all this stuff dries thoroughly (probably another 48 hours or so), I'll be ready to start fitting the pieces together.  There will be some vertical members to fabricate and paint, and boards underneath to provide feet in the right places.  And I'll have to finalize the design of the springs and fabricate 32 of them, hopefully consistently.  Then, the question of how to hinge the two sections together.  I want to find the type of hinge that allows you to lift upward and separate the two parts completely.  And, of course, the wiring.  Very simple, but I'll have to figure out where and how to mount the D-25 connectors and such.  Work continues...