Sunday, December 30, 2012

Medkit Preview

Still waiting on the final selector knob, and the Mysterious Part that does all the healing and stuff (Shapeways order sent in just before the holidays).

But outside of those, and the associated wiring (because the Mysterious Part just had to have some LEDs put inside it!) the Medkit is done.

I'll take some nice pictures soon.  Until then, these will have to do;




I didn't take a lot of work-in progress shots either, sorry.  Anyhow...boring text stuff (but not very much of that either) below the fold:


Saturday, December 29, 2012

Answering Questions

Sometimes I look at my blog sites and I see interesting search terms that led someone to here.  Sometimes I wish they'd stay and write me a note; because it is something I actually know the answer to.

Here's a random selection from this past week:


qlab how many tracks:  As many tracks as your computer can handle.  Actually, I've had more trouble over running several long tracks (ten minutes each) at the same time, as at some point QLab runs out of RAM and has to stream more data from the hard disk.  A friend of mine has had some breakup when running 10+ stereo sound files simultaneously on an old Mac Powerbook.

nanokey broken:  The thing that keeps happening to mine is the keys getting pulled off.  They can be put back, if you are nimble (and don't loose the little contacter boot/cup thing).  But it is enough trouble so lately I've just done without a few keys.

shield arduino ULN2803:  I've not seen this specifically.  I made one myself, of course.  Plus I made a one-board minimal Arduino + ULN2803 using one of Adafruit's darling perma-proto boards.  There are quite a few driver shields out there, tho.  Enough so you can almost certainly get the equivalent performance.  If not better (as in, many driver shields are arranged around latching registers so they give you more controlled outputs on fewer I/O pins).

oaklahoma little wonder:
  I built this prop long ago.  The description in the play is straight-forward; it is a frontier Viewmaster with a hidden switchblade.  Basically, a portable version of the peepshow machines popular at the time; you pointed it towards a light and looked into one end, and saw either a slide, or through various cunning mirrors and similar, more than one slide, of a pretty girl in various stages of undress.  In the specific device used in the play, if you know which catch to press, a knife comes out -- according to the script, the knife pops out the bottom and you then grab the tube from the rube and stab him with it.  The version I made was slightly more efficient; a spring-loaded rubber dagger came out the viewing end!

attiny button led pwm:
  Um, sure.  All of the above.  Trick to note; the tinys have only one or two internal clocks that can be used for hardware PWM.  These don't line up well with the expectations of the Arduino software so you are better off writing in C -- and be prepared to read up on register flags!  You can also do software PWM on any pin; I reprogrammed a Blink-M this way, and it fades okay without too bad a flicker even though I didn't use very efficient code.

Atompunk USB:
  now THAT is a nice idea!  I've got a couple of flash drives sitting around -- maybe my next prop should be a nice atompunk mod for one of them.  Dare I find a really small gear motor and put a fan on it?

Friday, December 28, 2012

Bah

The magnets don't work.  Next project, I'll plan how I'm going to fasten down the lid before I finish the sculpts!  So hot glue is going to have to do.

The dress nuts I ordered don't fit my buttons.  Which didn't look right anyhow.  So I filed down the shafts of the buttons until the new nuts would fit over them, pried off the buttons, clipped down the stems and painted the stubs black.  Then epoxied them into the holes (as they are now way too big.)  The decorative nuts were superglued over that.  Inevitably, at the last part of this last stage one of the buttons stuck, and in my frustrated efforts to free it I dinged up the new paint job.

Was also working on a very slight weathering.  Mixed up an acrylic wash, but it pooled and looked spotty and didn't seem to want to stay in the panel lines and around the letters.  Also mixed up a lighter color and dry-brushed some edges.  And it was all very messy and annoying and I have a headache now and at the end of it came back with a fresh coat of base color to knock most of that down because it didn't look very good.  Now I'm putting down coats of Krylon Crystal-Clear to seal it and make a sturdy finish.  Which is gloss, not the matt I'd prefer, but I'm not running out and buying yet one more can of paint at this point!

At least the water slide decals seem to be working now.  Given my experiences with dinted paint, the fragility of the decal, and the fact that there are buttons glued into their holes instead of threaded with proper nuts, the boxes are going to be more fragile than I'd like.  Not exactly the kind of thing you can toss around.  So one more thing to learn how to do better.

The desk is still covered in electronics scrap.  I just need to throw some minimal effects into the Medkit and I can clean up the desk/clear the decks for new projects.  Like the microphone repairs I'm sure to need before the next show opens.  Or the robot I may be building with my niece!




Next entry should be pictures of the finished props.



Oh:  just for laughs, here's an approximate list of the different "threats" the randomizer will pull up when the CBR Kit is set for "Simulated Threat" behavior. 

SARIN, CHLOLERA, TULARMIA, TYPHUS, SMALLPOX, NOVICHOK, BUFOTOXIN, RICIN, EBOLA, BOLULIN, MARBURG, ARSINE, PHOSGENE, CHLORINE, BROMINE, CYANIDE, ANTHRAX, SPECTROX, C DEIMOS, IOCANE

 The list is not meant to be complete or even representative; it is mostly a list of reasonable size of simulated threats that look okay on the display.  Seven-segment, 8-digit display, remember.  So "X, M, N, V, W, T, K" are all very hard to work out, "R, U, N, B, Q" are all lower-case, and "I, O, S" all look like numbers.  So "SARIN" displays more like "5Ar1n" and "NOVICHOK" looks something like "n0u1CH0H."

As the client and I have discussed, if war holds off for another decade the Morrow Project upgrades to LCDs or character displays.  And if they made it to within the current decade, it would be full-color OLED screens!



To add argh! to argh! as soon as I soldered the speaker down, clipped on a brand-new fresh 9V battery, and hot-glued the top of the case down, a software error showed up.  I still don't know exactly what is going wrong but after several hours of work I traced it down to one program line and commented it out.  So, now, when the simulated radiological threat is in the penultimate stage -- just before the Rad Alert triggers -- only the last two digits of the displayed number continue to change randomly.  Instead of the last three digits, as I had originally programmed.

I have suspicions as to what is going on, but it looks very much like a problem of interaction.  A problem where the engineering gets real instead of done cargo-cult style, that is.  I'm actually surprised I didn't run into trouble before, what with PWM'ing and playing tones at the same time, plus what are probably jolts of back EMF coming off the speaker.  It looks very much as if at some point, a buffer over-runs.  Well...it seems to work now!

Another complete oddity.  While the problem persisted, over the entire simulated radiological threat display sequence, the VFD would not display all the segments of an "R."  Every other letter or number was normal.  Not "R."  Which sounds even more like somewhere, a buffer is running over and something is leaking into program space where it isn't supposed to be.

Well, the Medkit is simpler.  I'm actually looking at three different functions (one power switch and two "easter eggs") but there is no micro.  Everything is hard-wired.  In fact, one of the easter eggs won't even share a power supply.

I think.  I will test if the VFD will fire up on a 3v supply but... 

Thursday, December 27, 2012

Sticky!

What's even more dangerously sticky than fresh superglue?  A supermagnet dipped in superglue!

I've been fastening the tops down on the Morrow Project boxes.  By attaching small neodymium magnets to the cases and bits of stainless steel to the lids.  With cyanoacrylate glue.  As I was attaching one, it flipped around on the tweezers, smearing them with fresh sticks-to-everything glue.  As I carefully wedged it free with wooden tools, it flew across the desk to grab on to the permanent magnet of the installed speaker.  In trying to remove it, I broke the tip of an X-acto knife and the broken tip struck me in the eyelid! 

NOT safe.  This is the sort of thing that should really be done with goggles at least, plus gloves, good light and ventilation, and plenty of sleep too.



Today was also the day to finish off the code.  And work with the water-slide decals.  So... my printer wouldn't make a clean job of it.  Neither of the copy shops I tried had anything that could work with inkjet paper.  My friend's printer wouldn't feed the thick paper.  Finally we got a set printed.  The first smeared into a mess despite a coat of Krylon Crystal-Clear.  The second came apart (and also showed signs of smearing) despite a coat of Blair Spray Fix.  The third I hit with three heavy coats of the Krylon and that finally worked.

Here's the artwork:


These are water-slide decals on thin sheets of polished tin (4 cm by 2 cm square). The white parts (like the letters) is exposed metal.  So far it looks pretty good.


At some point in the next few weeks, besides taking pictures of the final props, I want to write one combined post that lists the parts, gives the schematic, provides links to the 3d models, etc.  Basically, everything that I can provide electronically that would allow someone else to make one of these.

Tuesday, December 25, 2012

Stop Casting Porosity!

Volpin makes it look so easy.

The difference is between being able to stumble through all the steps, and being able to do them with confidence and control.  I made a better box mold and a much better slush-cast for the Medkit body, and the lid fit first try.  But there is a bit of alignment still needed and I did have to Dremel out the lid a bit to fit the electronics.  Which means I'm far below the level where I would be offering a kit to other people!  Heck -- my panel lines are still barely acceptable.

 Next project I have to mold I want to try a jacket mold.  I'm tired of going through so many bucks worth of silicone, and the mold boxes I've been doing are barely good enough to keep the molds from folding over, turning my boxes into parallelograms. 

I'm finally seeing the end of this.  Still waiting on custom-printed knobs from Shapeways, have another couple lines of code to make the capacitance-sensor triggered "injector" look right, and of course solder some minimal components into the Medkit.  Oh, and print out the data plates and so some touch-up paint.

Which sorta of segues into an attempt at a schematic for the CBR kit:


I can't vouch for the accuracy of this.  I didn't exactly draw up a schematic before I started soldering, nor did I document that well during the project.  Mostly I opened up the appropriate datasheets and made the appropriate connections on the spot.

In the upper left is a basic 7805-based regulator.  I left the power switch off the diagram.  Below it is the 6-pin programming header that works with my in-system programmer.  Left of center is a minimal Arduino, essentially; 22 kHz resonator, power and ground.  There's actually a .1 uf filter cap across the power leads I didn't bother to draw in.  And some people hold RESET down to ground with a 1 meg resistor but this didn't seem to be necessary.

The important part is the Supertex HV5812, which I found at Mouser; a 20-channel high-voltage driver designed for use with vacuum fluorescent displays.  Like the Soviet-made, old-stock ILC1-9/8 eight-digit, seven-segment display I am using.  I found those on eBay and they were shipped from the Ukraine (cheap, too!)

Above the HV5812 is a Recom DC-DC converter also picked up at Mouser.  It works, but just barely; 24 volts is low for the VFD, which really wants 30-60V.  It also wants a voltage-controlled AC filament voltage, but a small resistor works well enough for this application.  To the right of the Recom a power Darlington (the venerable TIP120) is operating as a switch to (over) drive the poor speaker with nasty square waves.  No attempt at a DAC or waveform generator of any kind here.

Two of the AVR pins are being used for a capacitance sensor using the Arduino library (many AVRs will do capacitance sensing natively as well, which is a more efficient way to go if you have lots of pins and want a fast reaction time).  The indicator lights (20 ma LEDs) are all running off PWM channels, and the two control inputs (button and rotary switch) thus are on the otherwise unused analog inputs.  The rotary switch is using a resistor ladder, thus allowing a single pin to detect a larger number of different switch states.

As circuits go, its actually pretty simple.  Or, rather, no part is complex; it is just a melange of different simple circuits.  The HV5812, for instance; high voltage is supplied to Vpp and the regulated 5v to Vdd, but the four control lines (clock, blanking, strobe and data) are just fed any four arbitrary Arduino digital I/O lines.  Wire up which ever is convenient and then assign them the right pin numbers in code.  The outputs are the same; I pretty much wired them one-to-one to whichever VFD pin was nearest, and then solved the assignments in the lookup table.

Friday, December 21, 2012

Beloved Denton

There's a thread at the Replica Props Forum about literary props.  Not props that are literature -- they call those "paper props" -- but props from works of literature that have not (yet) been turned into movies or television shows.

The one I've been thinking about on and off for a while is the pistol carried by James H. Schmitz's character "Trigger" Argee.  (Not actually my favorite character of his, but Telzey Amberdon would be more likely to carry a set of law books.  In a "reader," which is a very nice 1940's prediction of an eBook with Internet connection, but still...)

Trigger's weapon is interesting both as a high-end collector's item; a very expensive, classy but ruthlessly effective weapon suitable for someone who is a crack shot and makes a living on the frontier, and as the signature item of a strong female character from the Golden Age; as much a signature weapon for Trigger as the twin DeLameter's were for Kimball Kinnison.

That said, there are maybe ten words of unique description spread out among the various short stories and the one novel-length adventure, "Legacy."  Some sort of weapon appears in the cover art for the Baen re-issues (so far I've not seen an Argosy or other magazine cover from the time of original publication that features Trigger, and the only other artwork I've seen for "Legacy" also fails to show her weapon), but those aren't as much help as they might be.  That rather makes the design up for grabs.

For that matter, DeLameters or the Valerian Space-Axe have only barely been depicted -- and not named as far as I know -- in a Lensman anime that bore little resemblance to "Doc" Smith's epic space opera otherwise.  Or, of course, the Lens.  And it hardly matters what the latter may have been depicted as before; you walk into a science-fiction convention with a polychromatic jewel set into a wristband, you hardly need to add a plain gray leather outfit for the locals to "get it."



Anyhow, I've been thinking for a while of making some SF weapon that isn't from any particular movie or game.  And I've also wanted to go in a different direction than the brutal, heavy, highly-weathered aesthetic these days (and not in the some-what overused steam or atom-punk directions, either.)  More in something that has a boutique aesthetic; fine details and rich materials like expensive watches, cigarette lighters, etc.  So technical details, yes, but something that also looks expensive and well-cared for.  Not like a mass-manufactured gun that's been through a war.

Plus of course integrate materials, fabrication methods, and internals with the design process.  So instead of trying to cram LEDs into the shell, design the shape around the necessary batteries or circuit boards or whatever.  And leverage CAM, 3d printing, photo-etching; every time-saver that modern technology has opened up.



But it is hardly like I need a new props project!  For all the above ambition, I'm struggling to finish the seemingly much simpler Morrow Project boxes.

My first pour of the Medkit faceplate was a failure.  The pour holes were too small. 

This is my second two-part mold.  I molded the faceplate face up, first.  Then, since the original model is solid balsa, I flipped the mold and built up a thickness with clay, attempting a technique I'd read about to achieve a uniform thickness (you roll out cords, then lay them edge-to-edge to fill the space).

I was in a hurry to make the second pour and completely forgot to add mold release!  Fortunately, I'd put down a layer before starting the clay and it was enough to keep it from turning into a solid mass of silicone.

The second pour was more successful.  Bubbles mar several of the letters (to achieve raised letters on the model I attached styrene letters sold by Plastrut).  The backside of the hood needs to be shaped to fit the vacuum fluorescent display (although I'll probably be using the dead one, for simplicity, and back-lighting with a couple of LEDs.)  And all that sanding and patching and shaping seems to have altered the shape of the cut-out enough where it isn't a good match for the box anymore.  I'm not sure if I'm going to try to repair that with sheet styrene (or a lot of sanding on the box, once that is cast).

Ah, well.  A little more clean-up, and I'll be ready to mold up the box.  I still haven't decided if I'm going to try a two-piece mold and attempt thin-shell fibreglas, or just do a box mold and see if my hand is better at slush-casting now.

I've been flipping back and forth between adding details to the battery compartments on both boxes, and prepping the new models for molding.  Just yesterday I splurged on a Squadron panel scriber, which turns out to be much faster with a smoother result than scraping panel lines out with X-acto knife.  Except that the bulk of the Medkit body is the soft green plastic of an Army first-aid kit, and it doesn't take details cleanly, not at all.  Been a lot of go-around with Bondo spot putty and Rustoleum filler-primer on that one!

With luck I'll be able to pour silicone today for the last mold for this prop.  It will be a relief to clean up and put away at least some of the tools and supplies I have spread all over the apartment!



I keep thinking "this is the day" I can finally fasten the lid down on the CBR.  But as of this moment, I still have to touch up the paint job, re-glue the components that go inside the lower body, solder them to the mainboard, add a couple more lines of code to decrement "doses left" and play a buzzer/change the "injectable" status LED when all the doses are used up, and swap out the Atmega168 for a 328 because I'm down to the last 40 bytes of program memory!  Oh, yes -- and fasten down the lid, which as of this moment is probably magnets inside, and some dummy screws as decoration.  But I might epoxy some nuts and make the screws practical instead.

Wednesday, December 19, 2012

O.R.(W)T.F.

I had a short gig to record a chorus (and reinforce them as necessary).  At the very last moment (aka while we were loading in, a half hour before the house was to open) we changed from Clavinova to a Baby Grand, and moved the guest star 'cello quartet to the center of the horseshoe.  Oh, and wrapped the horseshoe around at the ends because the singers couldn't hear each other (even before the 'cellos fired up!)

So the resulting stage plot looked like this:

There's actually less space between singers and instrumentalists than I've indicated.  There is also the physical layout of the stage, which further limited my options for placement.

So my primary mics for trying to get singers up over accompanists were three condensers set at chest height and crammed in between singers and instrumentalists.  My primary recording device was a stereo set on the tallest mic stand I had available.


Unfortunately the nice mic bar we used to own had gone missing.  So I taped the pair of Oktava's to one of the home-made brackets for my mini monitor speakers, in an arrangement I promptly christened the "ORWTF."   (It was actually more like a narrow A-B setup, given the limitations of my improvised rig.)  An A-B stereo pair depends entirely on timing differences for localization of sound sources; as contrasted with XY which is purely level-based (plus some tonal differentiation).  The biggest problem with A-B is that it doesn't collapse well to mono; you get phase cancellation.

On the second day I added a spot mic inside the quartet; again improvising with the black electrician's tape and a table-top stand to make an XY pair sitting on the floor.  Had I the gear, I would have used either a crossed pair of figure-8's, or an MS pair.   The intention here was just to give me a spot mic with some localization to increase my available options when I go to mix down the multis.

The piano was on no-stick, with the front third folded back to expose the hammers.  If it had been alone in a room I would use a large diaphragm condenser four to six feet above the lid.  Instead I stuck a mic a mere sixteen inches from the tiny slice of exposed strings.

The only good luck I got was that on the first performance, the singers managed to end up grouped around my large condenser -- which I'd put in an omni pattern for that location.  This was pure chance and not repeated, however.  I've mentioned to the conductor that if they continue to work with instrumentalists, they either need to rethink where they use pianissimo, or start including awareness of microphones in their stage choreography.

Oh, yes.  And all this listing of brands -- two Behringer B-5's, two CAD CM217's (actually, one, as the other went bad and I taped a Karma silver bullet on to it with yet more black electrician's tape) -- sounds like I was making careful choices.  I wasn't, really.  This is what I had available.  But I will add that I've used both the Behringer's and the Oktava's before in similar roles, and the PG-81 has become my go-to mic for piano (although I recently heard a very nice result from an MXL on a grand on short-stick.)




So far the recordings sound decent.  I record in Audacity for stability and options.  The first step is hand-editing to take care of loud clapping, loud random noises and equipment noises that may be on the tracks -- Audacity is handier for this kind of point-edit.  Then I normalize and export as individual mono tracks.

Sure, you can tame some stuff with compression.  But one-of-a-kind events (like someone knocking into a mic stand) are better treated locally, not globally.  And most compressors don't kick on instantly; they leave the first transient.  In the case of a pop -- or a hand clap -- the compressor may pull down the average of the peak, but it will still leave the clipping-level peak intact.

In CueBase, I pan the tracks and chop and trim down to individual songs, and (often) re-normalize the individual slices.  Then on a per-song basis I adjust pan, EQ, level, and effects.  For some situations I'll need to draw automation curves as well (usually level, as when I have to ride a too-soft solo.)  This particular concert looks easier than most; they didn't have much in the way of solos and they didn't move into so many different positions (not like last year, when they arranged themselves around the audience for one number and entered singing on another).

I'm hoping, in fact, to basically use my AB pair, unsweetened, and bleed in just a little of the spot mics where necessary.  I listened to the four "solo" numbers by the 'cello quartet, and although it is a good concert hall sound on the ORWTF pair, the closer position of the XY pair at their feet is a much more exciting sound.  Almost certainly, my final mixdown for them will be a combination of both.

The most complex thing I'll probably have to do is some very small time offsets -- since the spot mics are hearing the sounds up to 20 milliseconds before the area mics.

Saturday, December 15, 2012

My New Love

(Janice Rand) Captain, look at my legs! (/Janice Rand)


No, this isn't a disease here.  This is Bondo Spot Putty.  Smoother than wood putty, harder than spackle.  Used straight from the tube and sets up in about half an hour.  Sands well.  It could be a little stronger, but it really does fill those smaller dings and gaps.  I expect it will work even better once I start using my new Rustoleum Filler Primer instead of cheap spray-paint.


In comparison, Tamiya Putty has an oddly rubbery quality.  It is a good match for the texture of plastic model kits, meaning you can sand without cutting deeper into base or patch.  But for the materials I'm working with now, it isn't a good match.  It also isn't designed to fill larger holes.

So the CBR still has the lid magnets, data plate, screws, other minor details to finish.  And the Medkit hasn't even been cast yet.


I borrowed a can of hammered-finish silver to paint my arrow.  I had intended to use that as texture and paint an oxidized black over it, but it looked good enough as is and I didn't have time to risk in painting experiments.  It was a quick sculpt anyhow (carved aluminium bar-stock with hand grinder and file, built up the shaft socket with Apoxie Sculpt).

The fletching was similarly expedient.  Wallgreen's kite string wiped with black acrylic, dyed feathers that were left lying around from a previous show.  Done without a jig, just tacking with super-glue and eyeballing them.  It got the job done; about five hours total for the build and the Stage Manager got a kick out of it.  (The only reason for the metal tip is so it would support the arrow when stuck into the gazebo).


Right now I'm in the middle of the ballet, but programming is almost complete on the CBR and I've also done up a new bar knob to be 3d printed:

I'm a little worried as some of the details are right at the margin of printability for even the high-detail plastic -- according to the Design Rules sheet at Shapeways, it can't even be printed in Stainless Steel (which would otherwise be my first choice).

Getting the knob printed pushes back the delivery date by yet another week, but it does really add to the military radio look in a way no other knob would.

Wednesday, December 12, 2012

..And this is my pet, Peeves.

Sometimes I wonder if there was a class somewhere.  There's a surprising number of people in theater who do certain things.  Certain annoying things.  As if they all took a class together where these things were taught as if they were good and proper things to do.

Or perhaps this is a convergence of thought.  The same logic that makes people independently hear one lyric in a Creedence Clearwater song as "There's a bathroom on the right."  Perhaps entirely independently, the burden of acculturation, of ways other things are done and ways things are presented in movies and TV, has led to these same stupid things.


1) Leaving screws half-way in.  Inevitably, a tech will loosen the screws to take down a flat, a panel, a jack, or even a scab, and will leave the screws in the holes.  This can't just be laziness.  You have to work at it to leave enough screw so it doesn't fall out, but remove enough so you can move the object that had been screwed down.

Okay, sure, I can see a possible theory going through their minds.  They are thinking that each screw into a piece of wood leaves a hole, and enough holes, the piece will be destroyed.  Except it doesn't work like that.  The lifespan of a flat or flatjack is measured more by the wood itself, and the corner blocks.  Those fail long before the number of screw holes get onerous.  And re-using screw holes also destroys wood; each screw reams the hole out more.

And, yeah, it does work if you are just popping it off to get behind it and you will put it back in the same place a few minutes later.  But the people who leave screws half-way out do this all the time.  Every time.  Including when the piece is going to be put in storage.  Or stacked.  Or thrown in the dumpster.

And what happens in the real world is the screws snag.  Chunks of plywood don't stack properly.  The screws get bent and twisted and snapped off in the holes, and gouge the wood much worse than a second hole would do.  And the screws get caught on things.  On fabric, causing expensive tears.  On people, causing painful ones.

It's stupid.  Don't do it.



2) Cutting the grounding pin off an extension cord.  This one just has to be a case of a little knowledge being a dangerous thing.  Presumably the pin gets cut or snapped off when someone finds they are trying to stick a grounded cord into an ungrounded outlet.  And they are just educated enough to know it will still work fine that way.  The electricity will still flow.

Through pipe clamps, through microphones, through the strings of electric guitars, through YOU.

Defeating ground is dangerous.

But, they might argue, they aren't going from a grounded circuit in the first place.  Well, that's really the problem, innit?  If you are plugging in a clip light for an orchestra stand, you don't need a fifty foot extension cord.  The majority of the time that someone is trying to plug a nice grounded cord into something ungrounded, is when they are trying to run a power tool off an ungrounded, under-rated, fifteen amp household outlet.  Or, worse yet, they started at one end with a nice grounded 20A outlet, but the first extension cord they reached for is one of those flimsy bits of 22 AWG zip cord suitable only for plugging in Christmas Tree lights.

Ninety percent of the time, the person who finds it necessary to cut the grounding pin off an extension cord is doing so because they are plugging the wrong thing into the wrong thing in the first place.

Oh, and as an aside.  Plan your runs.  Use a star or string topology for your pit wiring so power comes into the pit on heavy-duty extension cords, is broken out with surge-protected strips, and only THEN, after you have powered the amplifiers and other possibly noisy, power-hungry items, do you break into a fine capillary network of zip cord to finish up the orchestra stand lights.  Of course the musicians will re-arrange themselves in the middle of the show and end up stuffing too many wall warts into one strip and running nasty bits of zip cord to things that should never be on zip cord...but you can at least start them out wired with economy, neatness, and safety.

Oh, yeah.  When I find a nice grounded extension cord that has been sabotaged like this, I cut off the end.  When it gets re-wired, it will be re-wired correctly.  Ready Kilowatt to the contrary, electricity is NOT your puppy friend.   It will cause noise, it will cause fires, it will cause pain, it can even cause death.

A lot of sound people think that defeating ground is the FIRST step in solving a ground loop problem.  No.  It is the LAST step.  In fact; more often than not, the issue will be with floating grounds, and you'll get less noise by going around and making sure everything is properly grounded.



3) Staples.  I know it is a pain, but remove the staples.  Sure, in the press of events you may decide that a few tears in the duvetyne are worth it to get it off the platforms sooner.  So you grab fistfuls of fabric and pull.  But unless you are a cruel, cruel person, go back and pick out the staples later.  I've put far too much blood on the duvy over the years.



4) When a cord is taped to the floor, remove the tape.  THEN remove the cord.  Sounds so simple!  But nobody gets it.  They grab one end of the cord and tear the whole mess up as one.  The tape flips around and glues to itself and you will never get all of it off your cord ever again.  (Especially if it is duck tape, which should never be permitted inside the door of a theater.  When I see it, it joins the decapitated extension cords in the rubbish bin).



5) Fold it before you stow it.  I don't care what it is, folding tables or work lifts with outriggers, the tech will inevitably fold the loose parts just enough so they can shove it into a closet.  It will take ten times as long to get back OUT of that closet.  Stow the legs and other floppy parts properly.  Screw doors into flats.  Fold and fasten down jacks.  Remove loose shelves.  Come ON, people!



6)  Long thin things stored on edge.  Don't do it.  In the majority of cases, the space saved is an illusion; you had the footprint to store them flat without losing anything of importance.  Especially, don't get cute and store them inside stacks of plywood or flats!  They might look neat when you stack them, but sure as anything, the next time someone is shifting that stack to pull out a sheet, one of your little six-inch wide, eight foot tall pieces will come slicing out of nowhere like a guillotine.

I've lost work to those things (significant bruises meaning I had to take time off to heal).  I've seen rental furniture destroyed by similar.  I am only waiting for worse injuries to occur to someone.

If you have to stack on edge, then lash it.  Anything else is unconsciable.

But then, this is really another case of what I call "Magic Magnetic Garbage."  That is the theory that if you can somehow get it close enough to the garbage can, no matter how drippy it is, it magically becomes a solved problem (in reality, it becomes someone else's problem).  I am convinced that the people who slip a fourteen-foot 4x4 on end behind a cyc are convinced in their animal mind that once they've successfully set it down without it falling over, and backed away, it magically never again will be a problem.

The sad reality is of course someone will need to go back there.  Often as not, NOT the person who propped up a death trap.  And the end result is torn drapes and expensive repairs and swearing and bruises and, sometimes, worse.

Sunday, December 9, 2012

The Bassoon's Story

Sometimes an idea takes a long time to tease out to the point where it is complete enough to plan a project around.  Other times, the pieces fall into place quite rapidly.

I've been wanting to write some music again.  While working "Nutcracker" that desire got stronger; I was listening to Tchaikovsky's masterful employment of the symphony orchestra and felt inspired to get wrangling with those elements of tone color and combination again.  And then I listened to the Oakland Symphony and it pretty much decided me.

I've had a few vague projects in mind for a while.  One being a secular oratorio in echo of Hayden's great "The Creation"; one that explores instead the progression, excitement, and mystery of our scientific understanding of the universe and its origins.  Other ideas have been more inchoate.

When I opened my notebook tonight, the only two germs of idea was either to write something, or several somethings, to two requirements picked out of a hat; as in "write something in WALTZ time featuring PIANO,"  or "Write something in KLEZMER style suggesting a WASHER-DRYER COMBO."  Or, to write something featuring a solo instrument as a character in a story.

Then the pieces dropped into place.  A fugue or maybe a duet...use the "Harper" melody I wrote a long time ago...older adventurer talking to young dreamer...took an arrow to the knee...

Unfortunately, the idea as it exists currently is a bit, um, ambitious.  Not as much as a 3-hour oratorio, mind you!  But what I'm seeing now is a piece of "program music" written for (synthesized) symphony orchestra, telling a story in four parts and lasting seven minutes (if not longer).

1) Adventure!  Swashbuckling, epic battle stuff of the adventurer (the bassoon? tenor clarinet?) at his prime.
  //arrow to the knee// (orchestral percussion)
2) "Oh, tell me of the road" A young would-be adventurer (flute?  Oboe?) asks for stories.  Becomes a duet/counterpoint.
3) On the road to adventure/the flute's story
4) Crisis, rescue/re-introduction of bassoon, finale

(5 -- love duet and waltz?)

From experience, this is 2-3 weeks of writing.  I don't really have the time to delve into this now, but that might actually be an advantage; I could use the time developing the musical and harmonic ideas more completely instead of leaping into orchestral arrangement.

Monday, December 3, 2012

The Sound of Music

What does an actual Sound Design look like?

I am going to risk being more biographical than usual by giving a breakdown of a show that is currently in production.



As I've said in earlier entries, the elements of a sound design/responsibilities of the Sound Designer are:

Vocal Reinforcement

Orchestral Reinforcement

Effects

Foldback and Monitors


More below the fold, plus a pic of a special prop bonus.

Monday, November 19, 2012

Paleo-Dieting

Things are looking up.

I've got a rental offer on my rack of sennies and a short concert and some hours for the ballet (Nutcracker, of course -- what do you expect a ballet to be doing in December!)  Enough work to keep me busy until late Jan, although that isn't the same thing as enough pay to keep me fed.  And the first part of the year is usually a slow time in theaters.

So I still need to keep my eyes on other work/sources of income.



Before one of the checks I'd been waiting on came in, I was actually enjoying cleaning out some of the recesses of the pantry.  Some egg pasta that had been there for years, as well as a a lovely soup that came in the form of dried beans and herbs -- requiring overnight soak and a four-hour simmer and so on to cook.  Given time I might have gotten to the miso paste and udon noodles, which I seem to dig out about twice in a given year.

I was skipping lunch over the ten-hour work day, and walking to save gas (well, mostly to avoid having to find parking).  And I felt GREAT.

It's a bit of a paleo lifestyle.  We humans spent a long evolutionary span going for days between decent meals, and having to work hard to get that meal, too.  Well, evolutionary physiology is almost as much a quagmire of pop science and misconceptions and over-generalizations as evolutionary psychology, so don't try to take it too far!  All I know is that over a short term, I felt more alert and more fit than usual, and that is a good thing.  Enough that I almost missed having money and being able to buy food again.



The Morrow Project CBR is almost completed.  It is close enough I'm brushing off the sculpts for the Medkit and planning the casting process of that.  I think at this stage I'll just do simple two-piece silicone molds and slush-cast and glue it together (since I'm not trying to be crazy with internal electronics on that one).  And if the molds are any good, use them to experiment with thin-shell fiberglass (my latest reading suggests that the fiberglass eats even the almost indestructible silicone, meaning you get only a handful of pulls from each mold).

I spent most of my free time between performances writing a sub-routine that generates an incrementing random number (it creates n random digits and adds them to an existing stored 8-digit number).  I really need to study my C books more.  For some reason it was throwing up a ton of errors when I tried to pull a value from an array and add it to itself, so I was forced to copy the value to a variable and then stick it back in the array.  Which meant I couldn't do a nice loop/array sort of function for the overflow, but had to do it with a stack of nested if statements.

Any time you see more than three if statements in a stack or nest, especially if they are all referring to the same basic variables, you know you could simplify with a loop or boolean. 

But this all gets compiled anyhow, first via the Arduino IDE, then through avr-gcc, so a nest of if statements is not necessarily any worse at the hardware end.

So.  The software tasks to do:

1) Stack three or more of the "geiger click" subroutine to build an increasing threat (like the chem detector, which reads out a "parts per million" of the identified threat, and chirps the alarm (randomly) with an increasing frequency until it rolls over to full alert status.)

2) Split out the write_buffer part of the new incrementing random number generator so I can loop it with a static display.  The limitations of an 8-digit display; I can't just display "Accumulated RADS 456.34"  Instead I have to rotate through different screens.

3) Modify the rad alert siren.  The basic "timbre" is right (it isn't a wave generator, lacking in fact any analog capability.  What it is, is a mechanical speaker attempting to switch between two PWM frequencies at a fast third frequency, and creating all sorts of harmonics and noise in the process).  Anyhow, what it wants to do is stay on original pitch for an interval then fall rapidly.

4) With these parts, finalize the stages of the simulated radiation threat display.

5) Adjust the "injectable" light flash rate and make it linger into the reset with a flag for turning the selector to the TREAT position.  Right now it is using an arbitrary cut-off for whether the Universal Antidote will work on a given threat.  If I was really crazy I'd use a look-up table (or just organize the Threat table properly).  But then, the Threat table is a switch-case list -- I didn't go through the bother of creating a proper array for it.  And, yes, I did switch leads, to PWM a modern 20ma LED into looking like a vintage 2-5ma model.

6) Write the behavior for the "TREAT" position.  This includes a runtime-only counter (yes, the AVR is a modified Harvard architecture chip meaning a running program can actually write to the non-volatile "program" memory -- but I don't need to dig into that for a simple table prop.)



After that, it is pretty much soldering to the case components, glueing the speaker in, installing magnets to hold the lid on, and touching up the paint job.  I'd love to add a nameplate or stamp somewhere, but most of the ways of doing that would cost more money.  Well.....maybe could glue on a very thin sheet of metal and put a water-slide decal over that...

Thursday, November 15, 2012

Kudzu

It is said that good coding practice is dying as a consequence of Moore's Law.

But this isn't quite true in embedded computing.  Three days worth of kudzu code is now taking up a massive 9 KB of my available 12 KB of program memory.  Fortunately there are only a couple of functions left to write.

In a sense, they are still right.  I could write better-looking, more elegant, more compact and more ingenious code (not that these are necessarily the same thing!)  But it is more important to finish this box and take the lessons learned.  And if I have to, I have an ATmega328P lying around that would double my available program space.

It is also necessarily sprawling because of what I am trying to simulate; a combination of analog electronics and (shhh!) future high-tech.  So there are a lot of places where it "looks" right to blink a display three times, pause, then go to something else.  And getting the timing right on all these events is a bit of a pain.  And leads to a lot of nested loops.

Plus the need for transparency; to be able to switch states in the middle of a display sequence without the box throwing up garbage on the display.  To catch that is taking a whole lot of little weenie "If (so is still true) then (delete that and clean up)" lines of code.

Monday, November 12, 2012

The Morrow Progress

The CBR box is mostly assembled, and I've been coding up the behavior.  As is my wont, I've been thinking about the programming process.

But here's a pic:







Why is the pic so blurry?  Explanation and more boring text-ty stuff below the fold.  Plus more pics of me soldering things.


Job Hunt

The "Starving " part is getting too close to being literal.  I have over a week's worth of food in the apartment although that is mostly grains (aka some ten pounds of dry rice), and little that is attractive for breakfast or lunch (I'm currently soaking beans for a soup that MIGHT be ready by dinner).

So I'm looking for a third job.  Something I can fit in within the show schedule and other ongoing duties I already have.  And it hasn't been going well.  There's probably more design stuff being listed at TBA, but I can't afford the $70 membership to look at their listings.  TBA doesn't quite have the whole Bay Area wrapped up, but listings outside of their umbrella are more rare.  And, somehow, Mall Santa, DP for an independent film, and Egg Donor don't look attractive.

Wednesday, November 7, 2012

Cyber-Poverty

It's like something out of William Gibson.  More and more, in more and more places, "high tech" (aka electronics) is being worked on not in spotless labs with ranks of test equipment, but with rusty screwdrivers while propped precariously on top of a milk crate and surrounded by empty boxes of Chinese take-out.

It is a matter of perspective.  Technology has always needed to be patched and salvaged.  It has been happening from well before the days of background bicycle mechanics, probably way before the days of itinerant tin-smiths.  We just haven't (or at least some of us haven't) quite caught up on our Future Shock and we just aren't quite used to seeing shade-tree mechanics and third-world repairs and improvisations done to things that have LEDs and microprocessors and other digital parts.

Oh, yeah.

My laptop crashed, with my only copy of the software I was writing for the Morrow Project boxes.


Rant, and pics of things being soldered, below the fold.

Thursday, November 1, 2012

Oscar Wilde does Electronics

He did describe the event himself, but it is more usually told as a story; Oscar comes down to lunch one day and a friend of his asks, "Hard at work all morning, were you?"

To which the novelist and playwright responded "Indeed.  I just inserted a comma."

After lunch he vanishes back upstairs and is not heard from until dinner.  At which point the same friend asks "Another productive session, I hope!"

Unperturbed by the sarcasm, Oscar replies, "Most productive.  I deleted the comma I had inserted this morning."

Well, Oscar's excuse was that he was a perfectionist.  My excuse is procrastination.  Plus a middling amount of physical and mental exhaustion from opening weekend.  Being both a designer and a show operator takes a lot out of me mentally and emotionally.  And the long hours (and short rations) don't do much good for me physically, either!


So this morning, I inserted a resistor.


Wednesday, October 31, 2012

Show Time

Show is open, and I'm running FOH for the duration.  So I've got a bit over a full month of a steady 30+ hour-a-week job.  For a fair but still small contract fee (why we hate long shows, long intermissions, and added matinees...because we don't get paid more for working longer.)

Which means I really have to concentrate on outside paying work in those gaps between performances.

But first priority is finishing off the Morrow Project boxes.  I just picked up some fiberglass.  And I now know where to buy Oomoo in this area (although I want to try a brushable molding compound soon.)  And it turns out the local Orchard Supply Hardware stocks three of the magic chemicals I've been reading about lately on the props blogs or in posts at the RPF:  Bondo Gold, Bondo Spot Putty, and Rustoleum Filler-Primer.

(Speaking of paint, I'm still angry that someone reached in through my kitchen window and quietly stole all of my spray paint, including the fun and useful Krylon "Hammered Finish.")


Monday, October 29, 2012

32 Short Explanations About the Arduino (Not Featuring Glen Gould)

There is this tool called the Arduino.  That is how I think of it; as a tool.  I think of it as no more complicated to learn than a bandsaw.  And like a bandsaw, it is useful for some jobs, not so useful for other ones.

The most important thing I try to put across to the non-technical person is that the Arduino is not particularly technical.  It is designed to be easy to learn.  It is self-contained; getting into Arduino means nothing more than getting an Arduino.  You don't discover half-way in that you need some other part or some specialized tool or you need to learn a whole process the existing user base are so used to they don't even think about any more.

Really.  You open the box it came in (mail order, Makers Fair, Radio Shack, etc.), plug a standard USB cable in one end, download the free (multi-platform) software which installs painlessly with a couple clicks, and up pops a window where you type the code.

 Arduino:












Add USB cable:










Start the software and load the "Blink" example:















Okay...there are two aspects to this that might seem more "hairy" to someone just getting into it.  The first is that you have to attach the things you want to read or control to the Arduino.  And that means you have to learn just a little about voltages and polarity and the difference between a power line and a data line.

The second is that you do have to program.  If you have never programmed before it probably seems daunting.  Really, though, first-year German is tougher.  Programming in a friendly development environment like Arduino is more like using an English-German phrasebook.  There are plenty of example programs already in the installation, and more if you look around and ask questions.  And you can get a lot of projects working just by finding a sample program and changing a couple of lines.  It may look like hell and win no awards for good programming practices but who cares; the point is that it works.

My own experience is that I knew how to solder and once decades ago had written some really simple stuff in Tandy-BASIC.  And I'm not a very fast learner.  But I got my Arduino working and did a pretty complex task with it in under a week.




The thing I want to  make clear about this "tool" thing is the fact of the much-touted Digital Revolution.  You have heard the phrase "Microcomputers are in everything these days."  Well, they are, and the reason is, it is cheap.  And it is good engineering; using a micro is often simpler to develop, maintain, and expand.

Not all of these advantages translate for the hobby user, but the general idea is still there; it is often faster and cheaper to do it in software.

Say you have a project with a couple of blinking LEDs.  You could use the venerable 555 timer to make a blink circuit:

(Image courtesy of Wikimedia Commons).





 That's two resistors, two capacitors, and the 8-pin DIP to solder up. 

And here's the software equivalent:


 (Actually, only a couple of lines are the blink code; the rest is boiler-plate.)














Even for something as simple as this, although an Arduino board is nuclear overkill, it may still be the optimum solution for the project.  Because you can design for cheaper components, more efficiency, smaller footprint, engineering elegance, etc.  But any real-world project includes the constraints of reliability and fabrication time as well.  And for many of us, weighing twenty minutes soldering up a 555 on a perf against twenty bucks for an Arduino clone that already includes on-board 5V/3.3V regulator...

And when you add that changing the rate or the dwell is a matter of typing a new number (instead of going through R/C calculations, soldering new components, adding a trim-pot to the equation, etc.)...

Because once you add a micro to the project, you have automatically multiple input lines (with debouncing), output lines, as well as the ability to sleep for power saving or reset after time passes with no input, and the ability to create complex sequences of activities and directly link them to each other...

Because a 555 circuit can blink.  The equivalent Arduino circuit can blink a Morse Code message that is several pages long.




 At this point there are probably readers who are muttering about BASIC stamps, baby programming, cargo cult engineering, consumerist culture and gross inefficiency.

The heck with them.  I come from theater.  Our only question is "Does it look good from forty feet away, and will it hold up until closing night?" 

But more seriously, avoid the siren song of perfect optimization.  Optimize as far as is necessary and practical.  And stop. 

And, yes, the Arduino is far from the first, or the only, microcomputer of this kind.  The BASIC stamps from Parallax were an early favorite, and the Raspberry Pi is making waves right now.

Why I like the Arduino is that it really is training wheels, and training wheels of a good kind.  The Arduino hardware is built around the ATmel-made AVR microprocessors.  It is a standardized wrapping of that hardware with basic clock crystal, power regulation, programming ports, and I/O headers.  And it is open hardware as well as being open source.

The Arduino IDE, although far from a robust code development environment, is really just a java wrapper for the compiler, with a few macros to simplify parts of the code.  It isn't, unlike some systems, giving you a misleading picture of what is going on "under the hood," limiting your access, or forcing you to work within a unique and/or proprietary framework.  It is teaching you C.  Phrasebook C, perhaps, but C.  And you can, even from within the artist-friendly IDE, easily pass some bog-standard C down to the metal itself.  Heck -- you can poke direct values to the registers if you want to.

And you aren't constrained to live within the original profile, either in hardware or software.  I've used the Arduino IDE to throw software on to not just minimalist ATmega168 boards, but to the ATtiny85 buried within a BlinkM!  In fact, the Arduino IDE interferes so little with the process of getting working code onto an AVR chip, I find myself turning to it as often as I go direct to the avr-gcc toolchain.

The, perhaps sticking points with some, about the common Arduino hardware/software, is that an expensive FTDI chip is soldered on to every board, and a bootloader takes up a chunk of the available program ROM, both "just" so the board will answer easily to a personal computer on the other end of a USB cable.

But you don't have to accept that as a default or as a limitation.  Go via an FTDI cable or AVR-ISP.  Delete the bootloader if it really bothers you.  And use one of the many, many "-duino" variants that are built without the FTDI or USB or voltage regulator or even clock crystal.



Here's a typical Arduino clone (a Freeduino, in fact:





Here's a minimalist Arduino built on Adafruit perma-proto board (includes an 8-channel Darlington; that's the second DIP):




Here's a much messier minimalist Arduino in the process of being assembled with the parts to drive a 7-segment Vacuum Fluorescent Display:



And, yes, you can actually run quite a bit of Arduino code on the ATtiny series of microprocessors from the same manufacturer; here's a target board for ATtiny 13/45/85;

But if that isn't small enough for you, then go surface mount; the Arduino Mini or Nano, or an Arduino-compatible like the Fio or the Ardupilot, or a Teensy or Bumble-B:










Okay, so we have an Arduino.  How do we make it talk?  How does one, practically, connect to the outside world?

It depends on what "outside world" you are talking about. 

There is within the Arduino community a variety of "Shields."  These are add-on boards that stack on top to provide such things as LCD displays, tiny keyboards, sound cards, MIDI jacks, etc.  I mention these because they are extremely easy to use; just, literally, stick it on top.  Most of them are well-supported with code libraries so using them is pretty much plug-and-play.

I don't have any pictures because all my shields are hand-grown.  I'll show some of those in a moment, but I didn't want to scare the reader.

Because for a lot of applications, it can be as easy as sticking wires into the holes.

Here's the guts of my "Square Candies that Look 'Round":



The idea was to have a couple of small (fake) candies sitting on top of a box.  There is a Sharp IR sensor in the front of the box.  When any object (like a passing child) got within about half a meter of the box, the candies would spin around to show the faces I had painted on one side.

There is no soldering involved here.  There are no additional components.  Just the sensor, and the two servo-motors.

To make this thing, I took two miniature servo-motors out of the bag they shipped in, cut holes in the top of a cardboard box, and stuck them in place with hot glue.  Then I took the $12 Sharp IR sensor out of the bag it came in, cut a square hole in the front of the box and tacked it in place with hot glue.

Then I took all the wires and jammed them into some of the holes on the header of that standard Arduino you see there.

Servos have three wires.  Two have to go to power; those went to the clearly marked 5V and Ground holes.  The last is the data line, and it requires PWM.  Don't even worry about that that means; just know that only a few of the I/O lines of the Arduino support PWM natively, so look it up (or look at the silkscreen on the Arduino).

Similar for the sensor; the sense lead had to go to an analog input.

I wrote down which pins I was using.  Plugged in the USB cable and opened the Arduino IDE.  Opened a servo example and changed the pin number to match the pin I'd plugged mine into.

And, yes, there was a little more to the code than that, but getting the I/O to work -- getting a reading from the sensor and getting the servos to turn to the desired position -- was pretty much just opening an example and changing a few numbers around until it looked right.

Added a little black tape to keep the wires from pulling out, and the project was done.




Here's a slightly more complex-looking one:

This is my oft-used MIDI Button.  No internal battery; I usually run it off any USB power supply (a computer or a phone charger).  The jack on the right there can take a standard wall-wart power supply or a battery in a box...anything from about 6 volts to 12 volts DC.  There is a MIDI output jack on the far side, a test button and activity light on the top, and the screw terminal on the back is how I connect remote buttons to it.

Here's a glimpse inside:


All the wires from the project box are connected to short bits of pin strip, which are plugged into the standard Arduino headers in turn.

It isn't neat, but it gets the job done.

(If you look close, you can see there's a loose XBee node on a breakout board floating around inside.  That's using the 3.3 regulated power the Arduino can also supply on the header, and makes the MIDI Button able to receive a signal from my Wireless Staples Easy Button.)

There's a grand total of three discrete components in the whole box.  Each leg of the bi-color LED has a ballast resistor soldered to it, and there's a single resistor on the MIDI port as well.  Other than that, the entire thing...from closing a switch fifty feet away to a standard MIDI note event being output...is managed by sticking bare wires into the slots on the Arduino's headers.

I did mention shields.  Here's a double-decker sitting on top of my Freeduino:


That is another good example of nuclear overkill.  I mostly did it this way because I already had the proto-shield wired up, and I only had about six hours to work.  The proto-shield has standard headers that fit on to the Arduino headers.  It also has a smallish strip-board style space in which to solder parts.

This shield is set up with two parts; a second header for a small RF receiver board, and a ULN2803 Darlington array.  The board drove three sets of high-power LEDs in various patterns under radio control.

This one, at last, has a bit of real soldering in it.  But the electronics layer is still dirt-simple; the Darlington array handles all the buffering itself, meaning all you have to do is attach outputs from the Arduino to the input leads, a power source to the "supply" lead of the Darlington array, and your 60ma loads to the output leads.

Because the whole idea is to leverage something that is simple to hook up and reliable enough to work for "long enough" and get you back to making art.  Or cute little robots for the stage.


Telling the Middle

I've read a bunch of Instructables, and been following avidly the blogs of several builders and wizards -- particularly Shawn Thorssen (who just just got a Make Magazine cover) and Harrison Krix.  And I've noticed again how so many explanations of "how did I make this" talk mostly about the final stages.

For much of the prop-making stuff I've been following, the bulk of the blog entry will be about the mold-making, casting, and painting.  There's good structural reasons for this.  Those are stages where large things are happening that are easy to record.  Those are technical things that lend themselves well to explanation ("Mix equal parts by weight and tap gently to allow the bubbles to rise").  And, also, mold-making in particular is the most un-recoverable stage; if you make a mistake in sculpting you can usually sand and fill, but if you mess up the mold...  Oh, and these are also places -- particularly painting -- where there are long stretches of free time as you wait for paint to dry or molds to outgas.  And you have leisure (and a clean work-table) to take lots of pictures.

I'm being a bit unfair.  Thor does explain in several places how he arrives at the shapes he makes.  And Volpin goes into incredible detail on almost every stage of the build.

But there are still blank areas.  And that is, largely, because talking about the "art" part is so incredibly difficult.  You can talk about what your inspirations were going in.  And you can talk about the technical details when you started to bend metal (or whatever).  But how you got from B to P is that place where, I believe quite strongly, most people who do not do art see nothing but an un-crossable chasm.

It's an old joke, but Ben Edlund tells it well;


Plenty of people have written about this and much better than I can.  The only insight I can claim is that the process isn't as cleanly divided as it might look to the outsider.  It isn't really (as the recent meme goes);

Step One:  Gather materials.
Step Two:  ???
Step Three:  Profit!

Instead it is a continuous iterative, exploratory process that shades smoothly from "I have no idea how to even start this project" to "Now I just have to glue this last piece on and it's done."

At no stage are you entirely free from problem-solving, or having to make artistic choices.

And the flip side is; at no stage are you truly faced with the proverbial blank sheet of paper.

This is important.  This is extremely important.

No matter what the project is, no matter what stage of development or build it is in, there is always a way to move forward.  You may find you are moving in the wrong direction.  You may even progress a long way down this wrong path.  But even if you have to go all the way back to square one, you will still benefit; because now you know one thing that doesn't work.

And if you committed to the first attempt, and you made any progress at all, you've learned about the process, the tools; learned a thousand things that will make the next attempt easier.




A big part, for me, in getting through projects is the ability I have to judge how much I need to know, how much I need to plan, before pushing forward.  I firmly believe you can always get somewhere useful in the end.  The question is how much time, and how much wasted material, you can afford for that particular project.  The tighter the project constraints (time, budget, client requirements, safety issues), the more you need to attempt to project your understanding forward of the place where you are actually building. 

This is not another way of saying "how much to plan."  Deal with the fact that planning is an ongoing process; that late in a project you will have access to knowledge that you simply could not have had before you started.  Instead of thinking of the plan of a project as some sort of total blueprint, which is more or less detailed/accurate depending on "how well you planned," think of it instead as what you see in the headlights while driving at night.  Think of it as the projection from where the project currently is to some point in the project's future. 

But back to that blank sheet of paper.  When you need to progress, do anything that will create movement.  Think of it as operating an evolutionary algorithm.  Put a random line on the piece of paper.  Now you have something concrete that you can say "no, this isn't right."  And after enough random lines, you may hit one that makes you think "Well, maybe if it was slanted a little more..."

Or steal.  Find out how someone else solved the problem, and adapt their ideas.  Enough time and enough reworking and it will become uniquely yours.  Or borrow from nature, who doesn't care so much about copyright.  Or intentionally apply a random process and see if any of the results are something you like.

I talk about the "blank sheet of paper" because it actually isn't.  Manufactured paper, under real lighting, isn't a perfect surface.  There are subtle shades in it.  Very faint shapes already in it.  Look for those shapes and build on them.

In composing, the equivalent is to doodle on the keyboard until you randomly happen on a pleasing sequence of notes.  (And it isn't completely random; it is constrained by the shape of your hand, the instincts for sequential moves and the trained musician's understanding of keys and chord structures.  The same can be said for almost any "doodle" process, whether in sculpture or in writing code.)




This is true at all parts of a project.  At no point it is completely, 100% "art," some sort of divine inspiration being poured directly on to the paper.  There is always a technical element.  There are always constraints.

Which means there is almost always boiler plate.

You don't have to re-invent the core principles of Western Music every time you are just trying to work up a bit of scene change music.  You have a melody?  There are tried and simple routines to assign a chord structure to it.  Want to write a quartet?  There are well-developed rules for voice leading.  You don't have to use them.  But if you have no better idea, you don't have to stare at a blank stave until your eyes bleed; just fill in a typical First Species and move on.

You can always go back.  You can always try something different.  Don't hold out for the one perfect idea.  Don't hold out for the one truly original idea.  Don't hold out for the idea that lights up the room.  Just put something in as a placeholder, and keep moving.

I believe it is an illusion (there is always an artistic component to anything any of us do), but you could go through an entire art project making nothing but what appear to be mechanistic choices -- from Rules of Composition to Principles of Color Theory. 

And, yes, it might end up looking like rote work.  Uncreative, and uninteresting.  There is that risk.  On the gripping hand, however, if you are doing art for a living, you can't always sit on a mountain watching sunsets waiting for *INSPIRATION* to strike.  You still have to make rent.  The show is still opening Friday.  The client still wants his prop by Halloween.

I say again, the idea of some heavenly inspiration is a lie that separates the artist from the non-artist.  The non-artist prevents themselves from doing art because they have been taught to expect inspiration.  The working artist is under no such illusion; they are aware that inspiration looks a lot less like the Hollywood depiction, and a whole lot more like, "Well, we could just coil them up.  I'm not in love with that, and it would be harder to paint, but...well, actually, I can see some other advantages already.  I just gotta run this past Phil but I think we might have a workable idea here..."





Well, that took a turn for the theoretical.

What I wanted to say, is that in the props blogging, and in the electronics blogging, there seems to be a large blank somewhere between "I set out to build a..." and "Next we solder the resistors."

And I'm going to try, the next time I write up a project, to explain some of those steps I always feel (when I read other people's blogs) are getting glossed over.


Friday, October 26, 2012

On a Dilemma of the Horns

I am so very, very tired of having to apologize for late sound, and having to go with compromise cues because there is no more time to tech.  But I haven't figured out yet how not to land in that situation

Monday, October 22, 2012

Flags

"Peaked caps and jodpurs and black uniforms, swastikas armbands and Lugers in hand, totenkopf lightning bolts Art Deco wings; these are a few of my favorite things..."

My browser history is filled with material about the SS right now.  Plus a lot of the early history of W.W.II, particularly the anschlu├č, and a whole bunch of material on radio procedures in the heer and cryptography and so forth.  I have several pdfs on the hard drive and DropBox space, and -- even more scary -- videos of rallies and marches.  My dollar mp3 player is filled with German marching songs and other martial tunes.  I've been brushing up on my own spoken German, and have even learned to sing a verse or two of the Horst Wessel lied.

I work in musical theater.

All of the above has nothing to do with any National Socialist leanings on my part, but signifies only and exactly that the current production in tech is "The Sound of Music."  And is probably neither the first nor the last time theatrical activities can or have led to what looks like suspicious interests.



There's a great story I was told by a props person once.  They needed a bunch of accurate-looking modern weapons for a production, and a friend of a friend of the director worked for one of the big suppliers for Hollywood.  They would loan the guns needed to the production for a nominal charge, but....they didn't want to drive all the way up to the Bay Area.

So arrangement was made that each would drive half-way.  The meeting was to be in Barstow, a fairly small town in a rather barren stretch of near-desert.  And the convenient spot was outside of a Denny's on the outskirts of town.  And the convenient time was slightly before midnight.  And the guy from the prop house, and my prop master friend, both showed up at this darkened parking lot in the middle of nowhere driving black windowless vans, and as they were transferring lots of shiny (but completely non-functional) rifles and machine guns, the thought went through my friend's head that this would be a really bad time for the local police or sheriff's department to drive by.

I'm actually surprised no techie of the geekier bent (like myself) has gotten grabbed at an airport or somewhere else where bags filled with mysterious bits of wire and electronics and blinking lights raise the red flags for security.  Okay..at least it hasn't happened to anyone I know yet.  There are certainly stories around the Maker community of such things.



 Well, I'm not designing any other shows at this very second, and none of them have elements that are particularly charged.  My last show I was researching chocolate and the manufacture of confectioneries, and the show before that I was interested in pirates, Gilbert and Sullivan, and sleepy little English seaside resort towns.  And Atom Punk and Teddy Boys.  It was a strange production!

On the other hand, my current history is a lot of CBW stuff; readings on strontium 40, weaponized anthrax, the pan-atropine auto-injector, Castle Bravo and the Tsar Bomba...  But then, the friend I'm building this prop for is looking even more like some sort of crazed survivalist in his Morrow Project research.

Theater is a strange duck.  Although in an ordinary life it is easy to walk backwards into what will become a life-long fascination with something completely esoteric, theater is more distinctly imposed.  You may have no particular interest in the birds of Austria or Change Ringing or the Luytens bell or how to blow a boatswain's whistle, but the show of the moment demands you learn enough to allow the audience to suspend their disbelief. 

And maybe a little more...I haven't worked a production "The Wizard of Oz" yet in which we didn't trade a few bits of trivia about The Movie (or about the books, which are truly weird.)


Thursday, October 18, 2012

The (Slow) Morrow Progress

This week has been installing the electronics.



I learned a bit about casting on the first go-around, and as I install I'm learning how well the previous method works.  Which is...good enough.  But I want better.  The next pull, I want to try out a thin-shell casting method demonstrated by one of the amazing modelers at the Replica Props Forum.  What he did was, within a two-piece shell mold (backed up by a carefully squared mother mold), lay tiny scraps of glass fiber and build up a controlled thickness by brushing resin into the mold and the fiberglass reinforcement.

This box would be easier to wire up if I had a thin but strong wall with a controlled thickness.  And even better if I could split it apart, and fix the circuit board inside.  Instead I'm basically dangling a loose circuit board into the cavity, with a whole mess of wires going back and forth.


Here's the speaker, "injector" LED, and so forth being secured with hot-glue and epoxy and Zap-a-gap.  Fortunately, I can pull all the positive leads together (all the control channels I'll be using sink loads).

I would have used the two screw terminals at the bottom as a battery cut-off, but the biggest lumps of my first attempt at a rotocast are down there, and none of my drill bits are long enough to reach through them!



So I had several of the circuits working on breadboard.  It was too messy to keep going with alligator clips, though, so next step is really to solder up the final harness and then work on programming from there.  Nice thing about digital domain; although I might have tested everything off the same I/O pin, one I/O is just like another...none of the circuitry should care when I put them on different pins and then start addressing them individually in software.

I'm not using the milspec Dialights as they were designed.  I don't have the height above or below the panel.  Plus, I don't feel like setting up a 12V source for running incandescents.  So instead they are modified for LEDs.

The high-power LEDs were prepped with the appropriate ballast resistor.

Then I took the adapter coupling (a screw that goes between the lamp base and lamp cap, suspended the LED assembly inside with my third-hand jig, and filled it with hot glue.


I just so happened to have a bottle of Smooth-on Mold Release Spray, and that worked excellently to keep the hot glue from sticking to the tinfoil I was protecting my work table with.

Then the adapter was set into the hole and, because it needs to be secure in order for the light head to rotate, epoxied in place.

Here's the lighting test on the first one.  That trefoil shape is the natural result of the inner shutters of the Dialight panel light.


The VFD is hot-glued in place, and the backs of all the lights hit with a quick touch of black spray paint.  The rotary switch -- unfortunately it is only a single-decker, so I can't actually use it for a power switch -- has a resistor ladder attached to it now, making it basically a potentiometer with click stops.  That will go to an analog port on the Arduino, thus saving me a few I/O pins.

I still have one rotary switch and one LED to go.  Then I'll start collecting positive leads and otherwise tighten up this harness.


And on to version 0.2 of the circuit board.  It isn't a whole version number, because I never breadboarded the entire thing.  In fact, because of all those little dangly wires, I'm not breadboarding the VFD at all.  I know it lights.  Now the trick is going to be if I can get my high voltage supply and switch to work right.

My first "naked" Arduino; this is a pre-programmed ATmega168 chip stuck on a strip board.

Or, actually, an Adafruit "Perma-Proto" board.

This is a wonderful variation of a standard strip-board that exactly mimics a standard solderless breadboard.  If you have done a nice neat breadboard, you can transfer it exactly wire by wire to this thing.  And it is built to the usual Adafruit standards; plated through holes, complete silk screen, solder mask, etc.

Of course I didn't have a neat breadboard.  So I made this cludge instead.  And I also reversed a connection on the ICSP header.  But at least it lights...not just the power light, but the Arduino.

Unfortunately, THIS is the Supertex HV5812.  Big one, eh?  And it isn't going to fit on my little board.

So v. 0.2 is retired from this project.  I'm sure I'll have a use for an Arduino with 8 channels of Power Darlington (the ULN2803 you see on the right) soon enough.

So the only way to get everything to fit into my little box is to turn the circuit board sideways.  Which I did by hacking a chunk of a Radio Shack strip board.

 And it is typical Rat Shack quality.  The copper traces peel, the holes are oversized and unplated, and it is frustratingly difficult to get the solder to flow cleanly on the pads.

Plus of course I don't exactly have double-wide sockets lying around.  So a little more time with the razor saw, creating my own.

So here is v. 0.4 of the CBR controller.  On the top right is 7805-based voltage regulator, with the customary blinkenight to show the power supply is working.  ATMega168 on the top left, with resonator in the middle of the board (the ATtinys I like running from internal oscillator, but for this it is easier to wire it just like an Arduino).  The ICSP is crammed into a corner.  On the bottom right, the socket for the HV5812, and to the right, a RECOM RY-0924S DC-DC converter which is supposed to be able to supply up to 1 amp of 24 volts off of a 9v supply.  I chickened out on building my own boost converter just yet!

So far, nothing is completed but power and basic Arduino.  That LED in the middle there is a temporary addition while I tracked down an issue that was keeping the Arduino from booting.  Since it is an out-of-the-box with bootloader and all, it already has a "blink an LED on pin13" program loaded on it.  Makes it very simple to get to "Hello World."  Also a trifle wasteful, since my Adafruit USB Tiny ISP doesn't require the bootloader!

But, then, an ATMega is overkill for this project anyhow.  The current I/O needs are three LEDs (two of which could be PWM'd for extra realism), one PWM output for tone generation to the speaker (which could be done as readily with a digital pin -- I'm only doing square waves here, not waveform generation!), up to four pins to talk to the Supertex (clock, data, strobe, blanking), one analog pin to read the selector switch, one digital to read the button, and two pins taken up by doing the capacitance sensing (which can be done on a single pin in many of the AT series by using ATmel's own capacitance sensing library -- but that's more work!)

I figure another full work session to finish this board, and maybe a bit more to straighten up the wiring inside the box itself, before I am ready to start programming.  Then, since the whole point of this circuitry was to do full alpha-numerics on the Vacuum Fluorescent Display, I'm going to need a week to create some kind of robust display handler that I can then program with all sorts of activity; self-diagnostic routines, threat analysis, user alerts, etc.