"Sword and magic heeeelmet!"

Yeah, I guess I got bored at work.

I've been working "Ride of the Valkyries" and the silly idea occurred to do a "learning the trombone" video that just cross-cut from first notes to simple scales to, well...  And add a helmet and some flames or something. Except that I hate wrestling with my green screen and it is too small for shooting a trombone performance.

So I made this an exercise in exploring all the "if you don't have casting resin, here's a hardware store substitute you can use" techniques. Substitute my little shop at work for hardware store, and I have several things that that are not really hardware store. Like a bolt of muslin cloth, like some industrial resin, like the white expanded foam. Even barge cement.

So I did this without a real plan, without mock-ups, and with a lot of "oops" moments as one of the materials didn't behave as intended. At least at the end of it, I'd managed to throw out all my Oomoo and Rebound and three cans of Bondo that had all gone bad. So it helped with the house-cleaning, too!

If you really need the whole list, I made a rambling post at the RPF. The shell is glue-muslin, the horns expanded foam reinforced with resin mixed 3:1 with Durham's Water Putty to thicken it, the studs are cast in Durham's using a mold made of white bathtub caulk on an original carved from the end of a dowel.

So, yeah, learning experience. It works fine for what it was intended to be (really, I would have been just as happy with something even sillier and cruder looking. Maybe I'll add a shredded-paper beard when I do the video). The main complaint I had is too much going back and fixing stuff that didn't work right.

Sutton Hoo

Sometime in the 7th century an Anglian King was buried in his ship on the banks of a river in Suffolk, England. Most people will remember the Sutton Hoo helmet (which is on display at the British Museum.)

There were also sufficient fragments to reconstruct a lyre. Unlike the Greek Kithara with the separate crossbar this is a compact rectangular instrument that gives the appearance of being made from a single plank.

The historical playing style, as reconstructed by Master Dofinn-Hallr Morrisson, is that it is strummed with the right hand (plectrum or backstroke with the nails) whilst the support hand mutes selected strings autoharp style. It can also be plucked from the right hand, and a modern master has demonstrated drone plucking with the left thumb as well as pinch harmonics.

Acoustically, it is a cigar-box guitar without a fretboard. Which I expect would make it relatively robust to changes in dimension and shape. Most people who have made a Sutton Hoo-style lyre have modified them in various ways for ease of play and ease of construction. I borrowed several elements from other lyre builders for this my first build, relying largely on instructions made freely available by David Friedman/Cariadoc.

And, yes, I dream about grain-matched sapele and torrefied sitka spruce but I decided to make this a budget build; fast and cheap.



MATERIALS:

White Pine: a short plank of 1 x 12. The most common (and cheapest) lumber at any store.
Basswood (linden): an eighth-inch thick hobby board (8" x 24") from Orchard Supply Store.
Red Cedar: another OSH hobby board, quarter inch thick and 2" wide.
Brass rod: one eight inch, also from OSH's hobby supplies.
A pack of cheap acoustic guitar strings from Starving Musician.

Total materials about fifteen bucks. (Staining and finishing adds a bit, but the instrument plays fine without all that).


BODY:

First step was drawing out. I scaled Cariadoc's outer dimensions (8" x 30") to the wood I had, then after drawing it checked to make sure I could still get a hand inside. In case you are wondering, I went for 6" x 17", with 3/4" side rails (cut back to 1/2" inside the soundbox). That gives it roughly the scale length of a ukulele.

There's two basic ways to make the soundbox on this; either cut out a hole and cover front and back with solid pieces of wood (quarter inch for the back...and I'll discuss the soundboard soon enough). Or you can carve out the cavity. I chose to do it the quick and dirty way. The two long boards in the picture here are guides to keep the router from flying through the side walls should I slip.

(Later in the rout I added a top board and adjusted the plunge; otherwise the unsupported router can tip into the gap you are carving and ruin the piece.)

Three passes with the router, and a tiny bit of clean-up with a wood rasp, and the soundbox is made.

Next was cutting out the hand hole. Typical jigsaw work. (I'm spoiled; I also have bandsaw and scrollsaw available.)

After all the holes were done I used table saw and chopsaw to take the original plank down to dimension, bandsaw to rough out the ends, then bench sander to round things off properly. The interior cut, alas, had to be approached with hand rasp.

White pine is strong enough in these dimensions, especially for "gut" (nylon) stringing. The go-to wood is ash, although spruce, maple, cedar, yew and others are all nice alternatives. Plywood will work as well; again, this structure is under small enough stresses that regular plywood will handle it. It won't sound as good, of course, but it can sound good enough.


SOUNDBOARD:

Rough-cut the soundboard to slightly over the dimensions of the body, and pre-cut a sound hole. The Sutton Hoo lyres did not use a sound hole but several modern versions do.

I made mine an arbitrary size and position -- I went for roughly a third, as the third has magical properties in musical instruments (directly center you risk amplifying the primary resonance node of the body. And, yes, you can calculate the resonance frequency of the cavity. There's a simple formulae many luthiers use for sound hole size but it is based on an ideal Helmholtz resonator. Later papers show the critical factor is actually the length of the edge, not the area of the hole (which is why rosettes work, and why a violin has f-holes).

Basically, soundboard is like the head of a drum, and is where much of the volume is coming from. Cutting a hole allows the air inside the sound cavity to communicate with the outside, raising the volume but also changing the timbre (favoring the lower frequencies).

This is why you want a nice wood for the soundboard. Basswood is technically a hardwood and has been used for tonewood, but the best vote for it is that it is better than plywood.

There's an extra bit here. Pine and basswood are softer woods and might not support a tuning pin. As with other builders, I reinforced the crossbar with another wood (the red cedar). Routed down the thickness of the plank, stuck it in, glued down everything. I could have used more clamps.


TAILPIECE:

There are a number of different ways you can fasten the dead end of the strings. I followed another Sutton Hoo builder in carving a simple tailpiece out of red cedar. For simplicity in build I drove a dowel (actually, a piece cut off the end of a cheap foam brush) into the heel (where I'd intentionally made the wall a little thicker just for this. The tailpiece is fastened to this heel peg with a loop of steel wire.

The original tailpiece had this decorative hole. For strength I replaced it with a solid tailpiece. I've seen a bunch of different ways of tying on the strings but I haven't found one I like yet. Also, the test fit used leather laces. Those snapped. I tried a braided cord and that creeped. So now it is steel wire.

TUNING PINS:

The go-to for amateur luthiers is the zither pin; cheap, easy to install, holds well and doesn't take up a lot of space. It is what harps use, even the harp inside a piano. I was in a hurry and wanted to see if this could be done on a budget so I went for hand-fabricated brass.

Simple; cut out lengths of rod, pounded one end flat on the anvil, drilled a hole, the chucked it in a drill and "lathed" a rough point on the other end. Drilled a size too small and pounded them in with a block of wood.

BRIDGE

The bridge is also carved from that same budget-stretching chunk of red cedar.

Actually, three bridges. Basically, all sound comes from the vibrating string. But a string has a small cross-section. It moves very little air. To get a performance-level sound you need an impedance matcher. It's the same thing that causes a trumpet to have a bell. The soundboard provides the large area to shove air. The bridge acoustically couples the string to the soundboard.

And it is a dance. The violin bridge is thin and flexible because it is designed to steal the maximum energy from the string. A violin string is continuously energized and has very little sustain. Volume is a trade-off for sustain.

So my first bridge was too low. The second used a nut-and-saddle arrangement like a guitar bridge; the hard contact point steals less energy from the string meaning longer sustain but less volume. But that didn't sound good. So the final bridge was raw red cedar, and I'm shaving it down to be thinner and more responsive today.

Position is also critical. Unlike a guitar, I chose a captive bridge arrangement; it is held in place only by the tension of the strings.


STRINGING:

Yes, this is out of order. You don't need to stain and varnish your instrument in order to try playing it. Period instruments weren't. Well, not really (a little linseed oil at least).

For this build I put a knot in the end of each string and passed them through a hole in the tailpiece. Next build I'll try a bridge knot. Then wrapped around the tuning pin and through the hole. Get them all on and then stand up the bridge under them.

A nice benefit to the short scale length is I could get two courses from each guitar string. So this is strung with the top three strings of a nylon acoustic set; the G, the B, and the E (Gather Before Elrond).

The lyre is tuned diatonically, often omitting the second scale degree (aka for C Major you'd tune C, D, E, F, G, A) Also often inverted, starting on the third or fourth degree. I tuned mine to A Major, included the second, and since like all my examples it only has six strings that means I have no seventh.

Seven strings is better. Seven strings means you can play many melodies (just transpose down the octave) and you can "fret" all the triads of the major scale (with the appropriate inversions).


FINISHING:

This is more a "lessons learned" for me. It is really hard to tell when you've got the scratches out on softwoods. I sanded like heck, stained, and only then discovered a bunch more scratches. Sanded out the scratches, tried a different stain, and it made a lovely ancient-wood look but in the end I went for a darker serious instrument look. 

And really, I hurried too much. And no -- polyurethane is fast but it deadens the sound a little. Shellac next time.

Next time. Hardwoods, perhaps tuning pegs. Seven strings or better (historical depictions show a break around seven strings; either they have fewer and are played strum-and-block, or they have more and are played plucked like a harp, front-and-back-hand style). 

Rosette because why not (when I have a laser, after all). 

But, really, I've learned what I need from a Sutton Hoo. It is time to build a different lyre, or perhaps a proper harp...

Talk to the thumb

Wood stain is drying on my Sutton Hoo. I will not be surprised if the tuning pegs don't hold or the tailpiece snaps when I put it under tension, but no biggie. I have proper zither pins arriving Monday. The only reason I went with the brass pins is I wanted to see if it made a sound before I wasted a lot of time doing the finish work.

So I guess it makes sense I've started a Reaper file for "Uncharted Worlds" (the music that plays in the galaxy map and planet probe screen of all the Mass Effect games). The process is a little different on this one; found a MIDI file that seems close enough. Spent the afternoon finding voicing for it that matched the capabilities of my available instruments. And tried the top one (the ukulele part). Not too bad.

(Toughest part is my violin-trained instinct is to fret each upcoming note as soon as possible. For a guitar or uke part you may want to stay fretted in order to let the note sustain.)

Yes, there's a link. I started thinking about baby harps and similar when I realized "Uncharted Worlds" would need more and distinct voices than I currently own. And that got me thinking about instrument kits and one thing led to another...and there will be a fully detailed post on my new instrument when it is done and functional and I've had a chance to record a sample off it.



Bass practice is ongoing for the Hellboy cover. My thumb finally listened to me (I think it was changing my position; took off the neck strap and propped the bass on a leg instead. That freed my plucking hand from a support role.) So anyhow the thumb slide method is working for me now. Still some issues damping the D string but it is much less problematic than that A.

Yeah; on listen through playback other than headphones the test bass part I recorded really wasn't working for me. I need that finger plucked sound and I need to control the excess resonance. And that means learning proper bass technique.



And speaking of a Link:

While I was looking at various people's DIY harps and lyres I ran across builds of the "Goddess Harp" from Zelda: Skyward Sword. It is a nice-looking piece but I'm not sure how to make a functional harp from it.

Here's the sitch. The definition of "harp" is strings running perpendicular to the soundboard: in fact, they terminate in the soundboard. The lyre family -- as well as lutes and zithers -- have strings that run parallel to the soundboard and they acoustically couple to it via the bridge. (Think of a lyre as a guitar without a fretboard, and a zither as a guitar without a fretboard or a neck).

All of these work -- aka, project with volume and a good tone -- because there is a resonant cavity under the soundboard. For a guitar, that's the body of the instrument; try playing an electric guitar unplugged and you'll see exactly what that body does.

So the shape of the upper part of the Zelda harp is like a Kithara, the early Greek lyre. The strings terminate on a crosspiece which is suspended between two horns. However, in a Kithara the horns project from a soundbox -- the lower body -- with a bridge and tailpiece.. The Zelda harp is basically a croissant shape and the strings terminate along the inner curve as if it were a harp.

This would have lousy acoustics. Best I can think of is hide a soundboard inside, and then provide an opening for the sound to get out. There's also the issue of the crosspiece but builders have flattened that and added traditional tuning pegs to it without seriously harming the aesthetics of the instrument.

One alternative would be to make it an electric harp. Trouble is, you have to stick a pickup on every single string, unless they terminate in a single resonating piece (like, say...a soundboard).

Or go completely out of physical acoustics and make a laser harp. You could even stick a laser smoke generator in the body and even 5mW lasers would become visible. I think green lasers would look nice with the gold finish. Of course once you've started adding lights...why not make the harp body glow (gold, of course) as well?

But that gets into a completely different kind of project. One I could do. It is rather annoying, really; I've spent several decades collecting an eclectic set of skills from sculpture to fabrication to electronics and I would be entirely comfortable in approaching such a project. But I'm really more interested in learning the basics of acoustic instruments right now.

(Which also leaves out the Vulcan Lyre; although you could build an archtop, both the body shape and the canonical sound produced argues for it to be heavily electronic. Also, it is even more popular than the Zelda harp and there are at least two really excellent ones made by professional luthiers already.)

Say, I wonder if there are other fictional instruments of the string family? (Yes, there's the Skyrim lute, but I've watched a build of it and it is basically a shallow guitar with a lot of extra gingerbread.) I might be tempted to do that one but only as an electric and with full CNC.

Which is also a direction I'm going of late. Sure, it is fun to putter around a woodshop hand-shaping little bits of hardwood, but these days I'd just as soon leverage every labor-saving, time-saving, technological enhancement available. That's the thing I'm proudest about my Mini-Hoo, at least so far; that it took two afternoons to build (and one of them was mostly the sanding).

A Flicker of Light

"Birds" is closed. Here's what I learned about remote lighting effects:

This is one of the effects modules. Off-the-shelf, no custom PCB, and all purchased at Adafruit:

Feather MO/RFM69 board: Arduino-compatible with an ARM Cortex processor, hosting a 900mHz packet radio (as well as power regulation, LiPo charge management, and native USB capability)

NeoPixel Jewel; seven 5050 RGBW LEDs with internal controllers so the whole thing can be run from a single data line.

And a 3xAAA battery pack with switch and "JST" connector.

These are two of the "lamps" -- rather, incense holders. After fumbling around with a couple different ideas for diffusion the final choice was surprisingly low-tech; I stuffed bubble wrap inside.

And this is the setting. A little neighborhood church, minimal lighting setup. The transmitter (all the RFM69 chips are transceivers) is wired to a matrixed keypad and, to get just a little more power, a proper antenna also sourced from Adafruit. That's one of our musicians down there; the actors were doing photos before the house opened.



Radio performance? Fine. This is the lower power version of the chip and I've verified free-air transmission of half a block. I did have problems with one of the units when it was inside a brass ball; on the final weekend I stuck the wire antenna outside the lamp and it worked flawlessly after that. I also found they dropped connection when the batteries got low.

Battery? I didn't try to program sleep mode on either CPU or radio. One unit I turned off between performances and it lasted part-way into the second weekend. Another I left on night and day and it made it through two performances. A self-test and battery monitoring (which is quite possible with the transceivers) would be a good idea moving forward.

Intensity? Not spectacular. I only had eight standard theatrical fixtures (500W range) in the show, and even with all of them on the illuminated diffusor was quite visible. But they were incapable of putting useful face light into the acting area, at least in this configuration. I'm coming around to 3-5W as the minimum for a practical lantern or flashlight prop.

Software? This was a thrown-together mess, using a combination of library examples and repurposed Holocron software.

The most successful "look" I had programmed was a flickering lamp (since these are warm-white RGBW's, green+red to get an amber and a little white to make it brighter). It is a surprisingly good flicker considering it's simplicity:

At the heart of the program is a little function that compares a target value with the old value (for each channel of the LEDs), then divides the result by a rate, giving a float value of the difference per program cycle.

Then it cycles through, again by the rate, adding or subtracting this float, arriving at a new float (aka a fractional value), and temporarily converting it to the nearing integer to send it to the LEDs.

This allows me to fade up, down, or cross-fade between static looks. It also allows animation; for that, at each completion it will fetch a new number. In the case of the lamp flicker, this number is a random(constrained) intensity and rate. So sometimes it will quickly make a small change, sometimes it will slowly make a large change, etc., etc. The result is surprisingly realistic.

    By the way. I gave the musician one of my old Arduinos to play around with.

TechShop RIP

I can't say I didn't see it coming. When I gave them a thousand bucks for the current year's membership I did so reluctantly aware they might not last the year.

What I didn't expect -- what no-one expected -- is that one Wednesday morning their loyal members would find the doors locked, no-one answering the phone...nothing but a (belated) email later that afternoon explaining that they had filed Chapter 7 and no longer existed as a company.

Yes, I understand why the members were kept in the dark. They were still hoping to find an investor or strike a bargain. But on sober reflection I don't sympathize. The above translates as, "We were in such dire financial shape we had to hide our books from the suckers we were trying to entice to give us more money, so of course we had to lie to our own members lest they give the truth away."

So, yeah. I feel betrayed.

It was a useless effort anyway. When I realized TechShop was in trouble I went web surfing and everywhere I found future investors hanging out, they all knew damn well (and in better depth and detail than I did) how bad off TechShop was.




It might have been smarter to be open and lay out exactly what they were dealing with. The kind of help they needed went beyond finding some random guy in Dubai to send them an infusion of cash. They needed a restructuring, they needed a better business model.

But I have to wonder if this wasn't almost implicit in shape of the very thing we were trying to preserve. TechShop was Maker. It ran on the philosophy of throwing it together. A sort of laissez-faire approach to building where doing it the right way or even the safe way was de-emphasized in favor of experiment and originality and the freedom to fail.

I loved the hands-off approach. TechShop gave you just enough instruction to get started and at least know the obvious ways to cut your own hands off, then let you alone to study, learn, and make your own mistakes. The alternatives I've looked at are much more about the "community," with a touchy-feely atmosphere so strong it makes you look around for the Kool-aid. If you wanted to come in at ten at night, speak to no-one, log into the machine and make a few cuts TechShop was the place to be.

The thing that I will miss most is the multitude of options. Sure, I can get access to many of the operations and some of the machines. I can send away to Ponoko to laser. I can get printing done at Shapeways. I can build my own mini vacuum-former and I can do some machining at the machines at work. But this isn't the same as having all those tools right there to hand.

When TechShop was open I could laser off a little bit bit of material or even a stencil or whatever. Now it is either wait two weeks for Ponoko or use hand-cut with X-acto knives and what-not or simply find some other (probably less efficient) way of achieving the desired effect. I was just that day contemplating using the Brother CNC embroidery machine for a possible project -- that's how I found out within a few hours of the closure.

It is a more flexible, nimble, exploratory way of working. Having daily access also better supports iteration; you can try out ideas knowing that you can run off an improved part the next day. Having to mail off a file and wait two weeks for delivery (plus paying the money for the service) seriously constrains that.

The part I regret most is all of the leveling up. I found all the collectables, I finished the side quests, and I unlocked so much. Which is to say, I took (and paid a lot of money for) a great many Safety and Basic Use classes. CNC mill, CNC router, 3d printer, laser scanner, laser engraver, metal lathe, wood lathe...  That is all waste. The classes are far too introductory to be considered worthwhile general instruction in that tool, and they are too site-specific to save me anything at somewhere like, say, Crucible -- meaning more time and more money to get back to having full access to the same tools.




What could they have done differently? Well, for one thing they were badly organized and badly managed. And their crisis response was to do more of the same. When they saw budget shortfalls they spent less on maintenance and salaries and started shorting their own instructors. Which is to say; they removed value from the thing they were trying to sell in the first place. They also ran endless promotions, which besides bringing in short-term cash at the cost of long-term income (membership specials that over the long run brought in less than the cost of maintaining that membership) raised a pervasive odor of desperation.

I would have gladly paid more. I'm not sure how many other members would agree, but perhaps if they had been open about their books we might have. I'm also not sure it would have been enough.

Let me attempt a back-of-the-envelop here. Assume capital investment in the actual machines on the order of 20K per "machine," a half-dozen machines in four generalized groupings -- call it 20 and apply another 20 worth of smaller tools and supplies. So that's 800K to be amortized over ten years of service life before you need to spend an equivalent amount in replacement or repair. Double that annual cost to 160K to cover staffing, utilities, etc. (And that's probably an understatement; even with the expense of these tools I could easily see their amortization working out to only a quarter of the total annual costs).

I'd say there were fifty people there most times I've visited, with capacity say a hundred. That allows a standing membership of 400-800. Being generous, the latter 800 members would have to pay...$2,000 annually. Which isn't that far off (their Makers Fair specials ran that number down to just below $1k, but to compensate monthly members pay about %140).

I suspect strongly my numbers are far too low both on ongoing maintenance costs for the equipment and staffing costs. So...would I have spent 4K for a membership? Perhaps.

I'm going to also assume that classes are a wash; they money they bring in should go into decent pay for the instructors, because you want quality instructors but the class prices are about as high as anyone wants to go. Also, quality instructors means you could expand past the SBU's and start offering proper in-depth instruction for those that wanted it.




But here's where the model that works for me stumbles into the question of the actual market. And I have some deeply pessimistic ideas about that. I've noticed at other corners of the generalized Maker sphere that the emphasis is on "getting your feet wet." Everyone is offering introductory classes, introductory kits, first-time user specials.

Which is great, and also links into STEAM and the focus on getting more young people started into actually building things again. Leaving aside the gripe that so many of these kits and classes seem more about the illusion of building things -- the Arduino equivalent of a Paint-By-Numbers kit -- I keep getting the sensation that the biggest problem the Make movement faces is retention.

By which I mean I suspect a great many more people are "getting their feet wet" than who actually end up swimming. So that model of yearly members bringing in a steady cash flow may be wrong. It may be that many of the people at TechShop come in for a month, a week, even a single class. Or send their kid there on a STEAM outreach program. And maybe print something or do a couple name tags on the laser printer but don't stay.

And, sure, the typical cycle for the serious user/entrepreneur is to go three to five years during development and growth: until they can afford their own machines and don't need to continue paying membership. I suspect particularly the generalist (like me) is very much the minority. I made "props." Most people coming in on a regular basis are making "product" and they rapidly narrow down to just one or two machines that they do most of the work on (and can as their business grows afford to own themselves).

There's also the impression among some that there are members thriving on the atmosphere. Like investment bankers soaking in the artsiness of live-work loft spaces, they come to park on a table with their laptops and the free wifi and coffee like a more tech-centric Starbucks. Like the Paint-By-Numbers above, I keep getting this impression of people doing the sizzle and not the steak. Of putting on the beret but never actually touching paint.

Because, honestly, if you are young and hungry what you want is investors. Looking like the next Steve Jobs is a lot more important than actually soldering anything. So TechShop functions in this way as a combination meeting ground, bullpen, source of inspiration and photogenic backdrop.




And myself? I don't know.  This is a music week -- I did complete my bass case and post up a new Instructable (which already got Editor's Pick) but basically I'm playing, not building. The only reason I even looked in on TechShop yesterday was about an idea I had for a Bodhran case.

Am I phasing back out of prop work? Am I going to go in different directions? I don't know. About the only thing I'm sure of is none of the other maker spaces in the Bay Area look that attractive. They almost all seem small and ingrown and very clubby, with a sort of shipping pallet and cinderblock earnestness that only really works for the young and hip and at least slightly delusional.

The only offering that exudes any kind of professionalism is the Crucible, and they take it to the other extreme; serious fees, serious classes, and the pervasive impression I get from them is you don't dare think about doing your own machining until you've done five years of apprenticeship under the eagle gaze of the senior members. Plus they are mostly about fire and glass and metal and although I've flirted with the idea of casting it isn't enough to draw me there.

Really, I miss my lasers. (And the vacuum-form machine, and a lathe I didn't have to fight over).

Grading on a curve

Dracula is open. The LEDs are calculated and now it is up to the theater company to actually get around to purchasing them in time to install them. And I took most of today off to work on my friend's costume (I was really sleepy after being in rehearsal until almost midnight two nights running anyhow).

Vinyl (that's the generic term; you can call the embossed stuff pleather if you like and I usually do), is a real pain to sew. It alternately grabs and slips in the machine, bunching up at the slightest excuse. I sprayed the presser foot with silicone lubricant and that helps a little. A trick I just read about is to smear vaseline on the fabric just in front of the foot.

It also doesn't heal. You need to use a wide stitch or risk weakening the fabric so much it tears like a page from a memo pad. And you really don't want to cut open a seam and re-do it. You also don't want to pin anywhere but the selvage, which makes pinning even that much more pleasant.

Flattening the seams is almost worse. Because you can't press it. Only way is to glue. The one nice part is that if you glue a hem first, you can actually topstitch it for strength and looks without it going crazy on you.

But I also found out close to the end of the day that because it doesn't rebound the stitches end up loose, and you can't backstitch for strength because you'll just make a hole. Which means my seams were weak. Because my friend needed it for pictures I temporarily protected the seams with a few drops of fabric tack, but when I get it back I'm going to back all of them up with seam tape. Or bias tape and more glue (top stitching would be even nicer but I think it would look cluttered at this stage.

Interestingly enough, the actual show-used costume this is based on did no hems and all of the seams were "open," instead of stitching leather to leather they topstitched the leather to a black jersey knit. That gave the seams a little give for movement.

If I do another personal project with this material, I'll either use a similar trick or I'll do lapped seams. Or if I am lucky enough to have garment weight instead of the current upholstery weight, something like a flat-felled seam.




In any case, that's one more fixed-date deliverable off the table. Aside from lingering tasks with this LED thing I'm able to relax again. Just in time. My recovery from the last bout with the unknown illness was in danger of hitting a relapse if I had to keep up this week's crazy schedule.

Future (theater) shock

The Control Booth forum has started emailing notifications again so I logged in to see what they were talking about.

At least two of the projects I'd been tinkering with over the years have been done by others. And done well.

The simpler is the QU-Box, which leverages a Teensy (Arduino compatible with native USB capability) and some arcade buttons to make a dedicated controller box for QLab. Honestly, though, I was an evening of soldering away from doing it for decades -- but my Korg nanokey worked so well for me I never saw the point in completing the project.

Still, kudos to Simon for making a solid, functional device and offering it in kit form for the extra budget-conscious.

The other product I spotted was the RC4 wireless dimmer system. These are quite pricey but I'd still recommend them without reservation. I have nothing against hacks but by the time you come up with a working system you will have spent almost as much, and a lot of time you usually can't afford on a theater tech schedule.

And the guy is smart. He's thought of all the things I thought of, and put most of them in the box. A lot of people would just rig a bunch of PWM outputs and call it done. He's recognized the nonlinearity of output and subsequent color rendering, and put in a much more sophisticated version of the gamut look-up table I have running on my Holocrons.

He's also added what he calls Digital Persistence (another thing I've had to do in many of my projects), which is modifying the output so instead of coming on and going off near-instantly, LEDs will behave more like incandescent bulbs. This is easy for him because he's implemented another thing I was using as a paradigm; although direct multi-channel control is the default, his devices can run a baked-in animation in stand-alone mode instead of having to receive a constant stream of instructions.




Okay, I'd still like to see my prop light thing. But skip the wireless stage -- I'm not doing that much theater anymore and it adds too much complexity. Free-running behavior, preferably set through a full-on GUI running on a host computer and uploaded via USB. Built-in LiPo management, because again, AA batteries make more sense in a theatrical context but LiPo makes more sense for cosplay and other replica prop use.

And, here's the thing. Theatrical props, especially, it makes sense from a budget and time standpoint to take something commercial (usually a toy) and throw it in there. Often it is enough that it lights up. But even something more color-critical like a storm lantern or an old radio it's easy enough for theatrical purposes to wrap some gel around it or otherwise get it "close enough."

For a replica prop, there's more of an onus on getting it to look exactly right, so flexibility and programmability are good. But here it makes sense to leverage the mostly-done-for-you end of the hacker spectrum; Arduinos, various lighting boards, neopixel strips, etc. You pay a little more but given how many hours and bucks went into the prop, that's not a real problem.

The exception I still see is when a specific prop places something at a premium. Cost (because you need dozens of duplicates), space, etc.

For instance, my Wraith Stone. What I want it to do requires a dedicated board. And I'm fine with that -- just as I'm fine with people hacking up a $4 LED charm bracelet if that's what works.

Under Pressure

Actually, according to my new Omron sphygmomanometer (uncalibrated)  I'm running at the high end of the normal range. (My Kaiser doc says bring it in and they'll calibrate it).

Dracula is going into tech next weekend and I'm in rehearsals this weekend. I bowed out of Enemy of the People and Pinocchio but I've offered to advise, train, mentor and loan equipment. So it would be wrong to say there's no strings on me.

The sewing is going...meh.

The first muslin was way off. My friend pinned it up, I transferred the markings to fresh pieces, then laid the Simplicity patterns I'd just purchased on top as a sanity check. Turns out our alterations had brought my original pattern very close to what was on the Simplicity. Did a little further adjustment, stitched up a fresh muslin and that one fit decently. So now I can start cutting the real fabric.

The first fit of the bass case went poorly as well. On the plus side, turns out I don't like the look of piping on this one so would have re-done it anyhow. And now I know how to do piping. In any case, I'm disheartened by how long it is taking for what I thought was a simple build.




I still have hopes of finishing a few things. Priority now is things that are in the way of straightening up my room (there's so many half-built projects I can't even move a broom around). Bass case is one of those. So is repairs on the bass itself.

And, yeah, there's a bit of a stack. And I can't help thinking (especially as I make stabs at organizing and prioritizing) how many other things I've started that are now taking up closet space or, at least, mental space.

Worst offender is Holocrons. The three "final" holos are spread out over my desk waiting for detail paint and final assembly. Cluttering the floor by the desk are Sterilyte bins of Holocron parts, and taking up the shelf over the Behringer is the reflow oven.



Over by the futon are many of my metal-working tools, as well as another bin of metal stock and parts-in-progress for work. Half of those tools used to be in a bin dedicated to M40 builds. I've had a few people ask about them over the years since the last run and it is tempting to log a few more hours on that lathe I spend so much membership money to ensure access to.

Somewhere in there are also the prints for caseless rounds I should really finish up so I can determine how the 3d file needs to be modified.

Of course I'd like to make a new tool roll for those metal working tools. And the sewing machine has a nice big table to itself at my workplace (it is a work mate I'm helping with the costume for his kid). So seems like a logical time to do a little more stitching. In a moment of ludicrous optimism I even purchased three yards of a cute ukulele print and a Hawaiian shirt pattern...

It is amazing how much closet space fabric can take up. Between that and the sewing machine and the box of associated tools (zipper foot, spare bobbins, seam gauge, Fiskers, etc.) I would really like them out of the way. There's no room here for laying and cutting anyhow.

And, yes, before I got my present full-time job I was having some serious cosplay thoughts. Even
purchased a frock coat pattern, although those are a huge pain to stitch up. Not that these thoughts have quite ended, although my main wearable goal at the moment is Bronze Age gear -- sandals at the least -- for research purposes on the new novel.

Every now and then get tempted towards something like the Dragon Priest mask from Skyrim (there's a nice PDO I have right now and that's supposed to be fast....) And of course my next big personal prop project continues to be the Wraith Stone. And of course, one day would love to revise the 3d files and try to make a more "screen accurate" version of Lara's 2013 necklace...*

Fixing the bass reminded me that I have back in the closet (and, yes, taking up space) a fretboard and neck and the start of a body for a solid-body electric ukulele. I've pretty much decided I'm too impatient these days (and too conscious of how much money I get if I actually show up to work instead of doing stuff at home) to do the hand-carved hard wood trilobite I was working on, but there was the simpler Vulcan-Lyre inspired teardrop design...

Fixing the bass and putting it in a case will take care of some clutter. The Pfetchner is getting a new bridge but that doesn't take up any more room (I've got it at work anyhow, where I have a nice quiet space to practice). The Behringer is however currently useless to me because I have no simple way of firing it up to try out musical ideas.

And part of the fill of the various parts boxes taking up floor space at the foot of the overstuffed bookshelves is drivers and amps and other stuff to make "some" sort of keyboard amp/tone box. Very possibly based around a Raspberry Pi -- which also cleans out another Sterilyte bin full of Pi parts and accessories.

Still, a bigger hole in the pile will come from just putting the old mics and mixers and speakers in storage. I gave away the e-drum stuff and sold off many of the rack modules and can dump old cable (especially the to-be-repaired XLR I simply don't have patience to deal with anymore). Not as much fun as building, though.

I am at the moment terribly tempted by a brass casting of what appears to be a Mycenean sword. Would be quite a few hours of shaping and polishing and fitting a hilt, of course. Possibly as time consuming as getting back to my flint-knapping kit (which also could use a cute roll to protect the tools -- but in that case, something quite far from machine-stitched).

My prop weaponry desires also include, however, revisiting the Retro Raygun. Besides revamping the speaker and power supply for more volume, I'd really like a more Diesel Punk; less spray chrome, more well-used metal. And productionize it while I'm at it; fix the 3d files and run off a new circuit board so the thing could be a kit that anyone could assemble in a few hours.

And you know, that's not that scary a list, not right there. I'm still logging off to finish a Red Trolley and play some Skyrim.



* I have a new head canon on that protean prop. Hyperdiffusionism is real in the Tomb Raider universe, and an Ainu jade-carver was exposed to Maori greenstone carvings, thus producing a weird hybrid of at least two different cultures; a little bit Koru, a little bit Magatama. Well, that's what I'll carve. Would be a good preparation for the Wraith Stone; carve this somewhere between 2-up and at scale in clay, then scan it for a new printable 3D file.

We'll make it your way

I work at a company that is essentially using Just-in-time manufacturing technique. Our product line is nimble and always changing, and our catalog is deep, so ww essentially build each order as it comes in. And as a necessary adjunct to this, we only keep enough stock on hand to fill known orders.

That's basically what I was doing. However, the lead time on acrylic, PCB boards, small parts, etc. is enough that I had to anticipate Holocron orders somewhat and purchase those materials ahead. Unfortunately, I guessed wrong. It looks like I'm going to be stuck with unused parts. Whilst, simultaneously, being short of what I need to finish the remaining orders.

The problem is largely one of changes.

Shipped!

The first holocron was accepted by the Post Office. Now as long as it clears customs in Italy (and isn't damaged in transit....)

I've been scribbling on graph paper for nearly two months now trying to improve on the connection to the sense plate. Well, of course: after I assembled two holocrons and made up a detailed instruction sheet, I finally got the bright idea I'd been hoping for.

I'm still not wonderfully happy with the whole thing, but I'm willing to put them in boxes now. I'd set up a nice assembly line but there's only four or so that get completed and painted by me. The rest are shipping out as kits.



(The one remaining thing I really want is to program  in a few basic functions on the User Buttons. But dunno when I'll have enough consecutive not-exhausted hours to wrangle code).

Cold

It's cold out. Rainy also.

Good day to spend inside prop-making. Where I'm chasing down cold solder joints. Perhaps I need to scrub my PCB's before I start soldering on them. Or on the revised board (which I thought was complete until I thought of adding pins for a "talking" version), increase the annular rings on some of the critical pads.

No failure yet on any surface-mount component. But the hand soldering has thrown up two USB jack errors and even a couple of loose joints on the LEDs.

Oh, yeah. Talking. There's an Adafruit board that will trigger 10 consecutive (or random) sound files when a single pin is held low. Unfortunately they discontinued the version with an on-board power amp, which means I need to find space on the Holocron for two additional circuit boards. This, and even more ribbon cable, is so aesthetically displeasing I don't really feel like making this a standard option. After all, this is why I went through all the effort to make a single stand-alone board that combines charge management, USB hosting, and LED controller:

Also aesthetically displeasing is the sound. I experimented with the drivers I had lying around, and I needed to pump up to three watts into a quality driver before it could push its way out of the acrylic box and sound half-way decent. I've gone and ordered another of the surface mount transducers that failed me on the raygun project --

-- because anywhere else would create at the least a nasty shadow and possibly require a hole in the box as well. Besides, sound coming from a hole sounds like sound coming from a hole. It is a better effect if it sounds like the box itself is making the sound.

Pity I happen to know a little acoustics (and cabinet design). Because what this really calls for is a ported enclosure:

But that totally changes the look of the Holocron. And this is not a time to think outside the box. I've spent way too long refining on this particular box. It is time to brave the rain, visit the lasers and cut enough pieces to start shipping complete Holocron kits. (I have just enough to make one complete kit now, and I might assemble it myself just as a final check of the latest round of adjustments).

Or solder up the last of the current run of circuit boards. I stopped dead when I ran into odd USB behavior, but now I know what was going wrong and can fix it. I should probably solder up a complete "talking" Holocron before I order the version 1.1 boards, though. There's just barely space to put a couple more terminals for that...



(Oh, yeah; there's alternates. Best is go with Teensy and the Adafruit audio adaptor daughterboard for it. Skip USB hosting and in-place recharge and just put a string of Neopixels in for lighting. The Teensy does the heavy lifting of not just sound playback but DSP to equalize it. But that's costlier, still messy, takes up even more space, and requires I spend time programming.)

Help me, Obi-Wan

I'm in the middle of filling those Holocron orders. I'm already sick of them...been sick of Holocrons for months now.

Oh, but while I was restocking parts at Adafruit (I'm dangerously low on some of the Holocron components already) I rediscovered a very cute little OGG-based sound board they have there. It's got flash built-in, is visible via USB as a standard mass storage device, and can be as easily triggered from a free microcomputer pin as it can be from buttons.

So I actually could make a Talking Holocron without that much more equipment. Since I've kind of overtasked the CPU of the current Holocircuit already, this would be a re-purpose of my previous Cree-based board (or the next generation Cree board...long discussion there about what is going to go on it, though.)

And it would also be a good excuse to test Cree lighting of a Holocron; now that I've incorporated the internal diffusor I previously thought was going to be too complicated to do...

HoloBOM

I finished the Stolen B prototype today and opened up the thread at the RPF to start taking orders.

(Top image is the completed "Stolen B," including a prototype assembly of the final lighting diffusor, support structure, and circuit with USB jack. Bottom image is a mock-up using borrowed "Temple" shell and the lighting module from the "Stolen B" to show off the combination of "Guardian" diffusion and "Gallifrey" circuit layers.)

The above is also why I spent a few minutes today developing a BOM with parts numbers just so I could keep track of all the pieces properly. Here's the BOM for the design I've been showing off in earlier posts:

20.1 “Stolen A," assembled

0.1.31 “Stolen” shell set

0.1.31.1 Top

0.1.31.2 Side (3 pieces)

0.1.31.3 USB Side

0.1.31.4 Bottom

0.1.41 “Counselor” diffusion set

0.1.41.1 Diffuse top

0.1.41.2 Diffuse side (3 pieces)

0.1.41.3 Diffuse side USB

0.1.41.4 Diffuse bottom

0.1.51 “Circuit 2” set (6 pieces)

0.1.61 “Standard” diffusion cube set

0.1.61.1 diffusion cube top

0.1.61.2 diffusion cube side (4 pieces)

0.1.62 Support set

0.1.62.1 support top

0.1.62.2 support side (4 pieces)

0.1.71 “Revision 3” electronics package

0.1.71.11 “Revision 2” neopixel board

0.1.71.21 USB jack

0.1.71.31 Standard LiPo

0.1.71.41 Capsense wire

0.1.81.1 Magnet (4 pieces)

Tomorrow I'll probably solder up another couple boards, and scrounge and adapt from my discards pile to complete the "Temple," "Stolen A," and "Imperial Archives" prototypes. I need two Holocron gifts so at least two of those are going away (I can't see those particular ones, as they don't quite meet my standards for shippable product.)

Yes...working at a company that makes precision audio equipment has tainted me. I think in terms of QA and Reliability Testing and BOMs and MAI's now. But I need to; despite my original intention of making the cheapest possible kit that was also as smooth and simple to assemble as I could make it, the realities of the core design elements of the "Stolen" fork has produced a design that has a lot of individual parts and requires a fair amount of finicky work to assemble.

Now all I need is to add a proper tracking system for revisions...

Out with the old, on with the new...

...soon.

Yesterday was productive. Checks have arrived, bounced back from sick (after getting even sicker, that is), I finally did the "Gallifrey" circuit design for the Holocron and drew up my big attempt at the "Guardian" diffusion layer. Old-school; worked with ink (and lots of opaque white) on a drafting board because working through a graphics program was constraining my choices in the wrong ways.

While I was shopping for a new technical pen to complete the above I got an idea how to make the Wraith Stone work.

I've been pondering for months various schemes of multiple castings or fills to get the green inclusions. Well, after seeing some "ebony" Rub n' buff at the art store, I finally made the paradigm shift to accept casting the whole thing in translucent green, painting out the rest of the model, and dealing with the less-than-perfect way paint will interact with the internal lighting.

And actually, if I go clear instead of translucent color (using the LEDs to provide the color) I may be able to omit a casting stage and use the printed model straight.

So, yeah, I'm all inspired on this one now. I also came around on the qualities of the raised edge; a hand-worked look and resulting variation of thickness is fine. So cut the basic form from MDF then build up the details in Apoxie Sculpt. It's going to be built at about 3-up, scanned, and then printed to the actual smaller scale so not that painful to get the details clean enough.

The Wierzbowski Aberration

Got back to the metal lathe yesterday. Took an hour just to find where they had the tooling this time and set up the lathe and dial caliper correctly. There's a lot of little steps even starting from a pre-made grenade body and it wiped out two days of shop time.

In a fit of optimism, though, I worked out how to harmonize the varied sources for the best approximation of what the alternate Pulse Rifle loads look like.


Here's the situation: in the James Cameron SF movie Aliens there appears an iconic weapon which is described on-screen as firing "10mm caseless armor-piercing" and "30mm grenades."

The latter is for all appearances used by Ellen Ripley near the climax, by Lieutenant Gorman in manual mode earlier, and is worn in bandoliers by many of the Colonial Marines. And it is a popular replica prop -- more specifically, it is a necessary prop for Colonial Marine cosplay. And I am one of very few people who have made a machined all-metal version available for sale.

James Cameron admits to Aliens being "his Vietnam movie." There are references in prop and costume design to the American equipment of that war. The grenade attachment itself has similarity to the army M203. Because of both this historical connection, assumed doctrinal/tactical considerations, and some scant evidence from the film, various third parties have assumed there are alternate loads to the red-capped round Ripley is seen loading in the elevator scene (and using against the Alien Queen).

These sources do not quite agree.



To harmonize, I've put the movie first. The only dialog mentions are "30mm grenade launcher" and "M40 grenades." The main leeway I have in the movie references is that the scenes are usually in dim, often colored, light (the Lieutenant Gorman/Private Vasquez scene is monotone red light), and the grenades are rarely in focus.

For instance, this image; the scene is not in white light but it is unlikely the safety cap on this particular grenade is red. Blue is just barely possible. It also appears to have only a single stripe but as the grenade is slightly out of focus there might be two. It also appears quite strongly to have a straight-sided, flat-topped cap, with no curve or taper.

This is a cropped and rotated screen-shot from the elevator scene; identified with high confidence as the standard M40 load.

Of course, it must be pointed out that there were a very small number of "hero" grenades carved from actual aluminium snap-caps by the movie's armorer, Simon Atherton. The majority of what appear in bandoliers on uniforms are likely to be wooden mock-ups painted silver. I have seen images of one such, but insufficient provenience to know if it is screen-used. In several screen-shots the grenades show visible wearing or flaking of the red paint.

In any case, the aggregate data from the film is that at least three cap colors appear, those grenades are otherwise identical, and no other shapes are seen. With the exception of Wierzbowski (I'll get to that).



Next comes organized third-party listings, such as graphics found from various sources (one is tentatively sourced as from the Aliens Legacy Forum. As an example of these secondary sources, The Aliens Technical Manual has sufficient errors right off the bat to remove it from any primacy against other aggregates of alternate designs. It also, perhaps fortunately, has few images and relies on verbal descriptions. There are, fortunately, no real disagreements in nomenclature between these, although no two sources give identical selections. It is in the shape and coloration that the major disagreements lie.

Below this are individual fan-made creations, as most of these lack identification labels and many are guided primarily by technological limitations, not by artistic considerations. They do, however, take primacy in clarifying the kinds of details that a physical prop shows off better than does a stylized graphic.

Lastly, there is reference to real-world analogs and presumptions about mechanism and doctrine. I would love, for instance, to argue from real-world human-machine interface that different loads should be different tactually; the soldier shouldn't have to guess in the dark, or in dim red light, which of several otherwise identically shaped loads she is reaching for. But there is a ready-made answer within the film itself; the film is about the hubris of technological fixes and the real-world failure of all that fancy gear when facing a less technologically sophisticated enemy who is smart, tough, and on their home ground.



So here's the harmonization:

M40: HEDP (high explosive dual purpose), this is an armor-piercing shaped charge with sufficient blast radius to be used in antipersonnel mode. It is dual-triggered, on firing, and manually by removing the safety cap and pressing on the button. It has a specific groove pattern, a "parting zone" that appears to be a crimp, an a red plastic safety cap with one white stripe. There is some argument that "HEDP" is meant to refer to the dual-role as a hand grenade and may have no specific armor-piercing qualities.

M38: HEAP. Presumed optimized towards armor penetration, this might actually be a sabot instead of a shaped charge. It is identical in body pattern; it may be a poor choice for load selection in the dark, but might be justified as interacting with the Pulse Rifle's internal mechanisms. Going by the Newt close-up, this has the same plastic safety cap in green.

Here's where things get interesting. The graphic I found at Aliens Legacy gives all the rounds as having tapered caps. This clearly disagrees with the film. The Aliens Technical Manual only shows the M40 cap, and gives it as tapered. The tendency in other secondary sources is that the M40 cap has straight sides, the M38 tapered, and the M51A has a rounded top to the cap. The tendency is also in secondary sources to show all rounds as having double stripes. Most of this is clearly contradicted by the film. However; almost all secondary sources agree that the first three of the grenade family have an identical groove pattern.

M51A: Bounding anti-personnel. This is a clear analogue of the real-world "Bounding Betty" mine. It seems odd to put in a grenade, but this is consistent enough across third-party sources and fits so well within the milieu of the film we just have to assume some kind of auto-righting mechanism. Same groove pattern, straight-sided blue cap with dome; of the third-party sources that give each of the top three a different safety cap shape, the consistency is that M40 is square, M38 is tapered, and M51A is straight-sided with a rounded top. It isn't required that under every safety cap is an identical button, but given the auto-righting justification above only a sabot round makes absolutely no sense in that kind of dual role. (There are other button inconsistencies later, so even this isn't beyond possibility; perhaps they simply used the same shell with different loads.)

(A different problem with real-world analogs has to do with the specific blue. They appear to be a light blue, far too similar to the distinct "training round" blue standardized in the US Army. I guess we must assume that semiotic standard has changed by the period of the film).

There's a last interesting possibility; the clearly, tactilely distinct caps could be a late innovation. Given the murk of the film I don't think there is any scene showing blue-caps that can't be justified as having domed tops that just aren't properly visible in that shot. The same justification could be used to assume tapered green caps; this would make the "Newt" grenade an aberration explained as old stock from before the change-over (since they were pulling every bit of salvage and hidden-in-pockets ammo for their defense). It is also plausible they were all tapered at some point and the manuals are using outdated images.

For Aliens cosplay, however, straight-side caps is consistent. They are also easy to make. So this is why I say my props above are almost correct; the only change I would make it to add a slight dome to the blue cap.

M108: Canister. Presumably the Sulaco crowd didn't pack any, because they'd certainly have come in handy. The third-party sources are remarkably consistent in showing an identical groove pattern to the "big three," no safety cap, and a broad flat nose with some sort of black plastic disk. This is clearly explainable as some sort of disintegrating cover over the payload. A manual fire button also does not seem to make sense. There is some argument that what gets ejected would be different; does the body of the round fly downrange then a secondary charge kicks out the shot? In any case, this is a straight-forward build. (But also superfluous for straight-up Sulaco marines cosplay).

M60: WP/incendiary. The sources are a little unclear as to the exact weapons action here but white phosphorus is very, very Vietnam. The manual states white markings, all other sources give yellow. The sources (all sources are third-party, with one possible exception to be discussed) seem to converge on it having no safety cap, and a domed top with a wide, flat button. This is quite consistent with secondary employment as a hand grenade. The major disagreement in the sources is whether it shares a groove pattern with the "big three," or whether it has a unique groove pattern and a yellow paint band on the lower third.

And here's the Wierzbowski problem. In some scenes this one character appears to have a grenade with a yellow cap. And it appears to be the same square safety cap as the M40. So here's my explanation; Wierzbowski made a field modification. As issued, the M60 has a yellow plastic ring around a metal button (similar to that of the M40 but wider and less tall). Either Wierzbowski didn't trust this, or the ring functions as a safety and is considered difficult to wrestle with in the field; either way, he has replaced it with a discarded M40 safety cap and dipped it in the same yellow paint other marines have been using to paint slogans on their armor and helmets.

The other issue with the M60 is harder to reconcile. I'd argue against having paint on the sides as that could foul the weapon, but the only third-party depictions of the smoke grenade also show color bands on the grenade body. The tie-breaker has to be the movie; a yellow band should probably have been as visible as the yellow cap, thus, we have to assume this has the same standard body as the M40.

M61A: Smoke. This is the only smoke listed in any of the secondary sources, and in that source is shares a groove and banding pattern with the CS grenade. Doctrinal similarities seem to call for a variety of colors, and those would you would think have different nomenclatures as well, but none of that is provided. It has no safety cap, and a similar rounded top and broad flat button as the M60, lacking the color ring on the top (what I am assuming is a plastic ring that may function as a safety clip). The groove pattern is definitely different from the M40 standard, consisting of two wider grooves creating a defined band which is colored with (one presumes) the color of the smoke. The button may also share the same color.

M67A: CS. This is an odd one; it either shares a banding pattern with the M61A or has the same basic groove pattern as the M40, however, the majority of sources are consistent in giving it two narrow red stripes which may or may not be in shallow grooves. It has a gently domed top, no safety cap, and also lacks a button. For this, I simply have to wave hands in the direction of assumed Colonial Marines doctrine. Since they aren't visibly carrying protective masks, perhaps it was determined that this payload was unsafe to deploy at throwing-arm range.

M72A1: Starshell. The depictions are consistent; this lacks most of the standard groove pattern but has longitudinal grooves running down the length of the body. It like many of the alternate rounds has a domed top and no safety cap. It also has a button. The conservative answer here is that this is a self-righting shell, like the M51A, and thus can be hand activated as well as fired horizontally (instead of requiring the operator to point their weapon at the sky). Other possible answers are that the button is non-functional, or only looks like a button. Lastly, the technical manual claims it is marked with an embossed "S." This is not entirely inconsistent with the nature of the graphic depictions.

M230: Baton round. I didn't notice any depictions on my earlier searches. This has certain practical difficulties, depending on exactly what parts of the round can be and are extracted from the shotgun-like action of the weapon (hurling a metal case down-range would rather contradict the intent of a baton round).



Conclusions:

Oddly enough, the general answer to the question of making alternate loads available for cosplay is a simple one; paint the caps different colors. This even applies to the Wierzbowski; cosplayers are more likely to want to mimic his documented field modification than the hypothesized standard-issue version.

The majority of the alternates lack safety caps, which is mostly to the good, but they also tend towards gently domed tops -- which are hard to machine. They also tend to buttons, which are a known labor issue (as a reminder, my last machining trip took over four hours just to set three buttons). About half of them also involve body colors, which could be an issue (especially if chambering is intended).

Lastly, they just aren't that interesting. Only the star shell is significantly different-looking and requires enough new machining tricks to be really tempting.

The light went out!

Alternative title (for those who don't remember Ralph Bashki's Wizards); "Hey! Who turned out the lights!" (One of the freakiest Doctor Who monsters ever!)

I tested the load sharing and charge circuit on my new board. The battery I had been using for testing was pretty badly drained and after waiting two hours it was a relief to see the "charge" light finally go out. Means the schotkey and MOSFET are doing their jobs correctly. Next up is install it in a holocron for a lighting test. Then write some quick-and-dirty code to test the user option buttons.

Taking a step back, this is a big change in how I do electronics. I was just window-shopping at Adafruit and I realized I don't see myself needing any protoboard soon. Or even a lot of hookup wire. I've pretty much moved over to PCBs.

This is actually the previous version, plus my first-ever surface mount PCB

To recap, this is the process of the Holocron circuit I'm testing now;

1) Drew up the schematic in EAGLE

2) Ordered parts, mostly from Digikey

3) Drafted the board in EAGLE

4) Sent the EAGLE files out to OSHpark, a board making company.

5) When all the mail had arrived, stuck the smaller parts on the board with a syringe of paste and then put the board into my T-962 to solder them all at one go.

6) After the board cooled, hand-soldered larger components like the USB jacks.

7) Attached my Adafruit USBtinyISP to the new board's header, and flashed the on-board CPU with the software I'd written in the Arduino IDE.

8) Test and install


The first disjunct from how I did things as a teen is although I still have a big parts box, I don't use it unless I've made a mistake or need to test something or are too impatient. For the most part, I spec out the exact components I need and find them through the parametric sorting system at Digikey.

Digikey is very friendly towards small orders, and has a huge catalog. What makes it navigable is their parametric system; the usual method is to drill down, specifying the most important values first and winnowing down the choices.

The next big change is going to printed circuit boards. There are a number of fab houses now that will do small prototype runs for cheap. So I do a lot less of assembling components on protoboard (although that still has its place). PCBs allow me to make a denser, more compact board, they offer much higher reliability, they are faster, and lastly, they are the only practical way to include surface-mount components.

Perfboard construction. Even protoboard is neater (and faster) than this!

EAGLE is the key tool here. There are other programs to draft PCBs. EAGLE has a hobby version that is essentially full-function (just restricted in board size and layer count). It also has a schematic editor, and the nifty thing is, board and schematic are automatically linked. So the software will ensure you route your copper traces to make exactly the same connections as are shown in the schematic.

There are software tools out there to simulate the circuit itself. I haven't used those yet. Schematic is helpful enough. The big trick with EAGLE is parts libraries. There are many libraries contributed by users (the big hobby vendors like Spark Fun and Adafruit have libraries for most of the parts they sell) but I'm afraid not all the footprints are trustworthy. So the trick with EAGLE is to slowly build up your own unique library of trusted parts, parts you have personally verified on a PCB you have made. Fortunately, the EAGLE editor is odd, but useable; I've several personally created parts that have now been tested in production.

Again this is the previous version. This is most of the layers turned on in the EAGLE display; top copper, bottom copper, silkscreen...

It is quite possible to hand-solder surface mount (some crazy people even hand-solder the seemingly impossible, like BGA components). Faster, neater, and more electrically sound results come from reflow soldering. Basically you put a specially formulated paste of microspheres of solder in a flux base on the board, plop the components on top, and then carefully bring it to a calculated temperature over a carefully timed interval so the solder melts, flows, and then hardens correctly.

The software-controlled infrared heat lamp of my T-962 reflow oven does this quite nicely (many people have improved their T-962's, many others have made their own out of toaster ovens and microcontrollers).

The hat is not essential to operation. A couple of fire bricks from my brazing days, however, are; it blows some pretty hot air out the bottom when in use.

And then I'm in the Arduino infrastructure. Arduino is basically a wrapper (you could even think of it as training wheels) around the AVR series of microcontrollers. I spent a while learning how to write straight C code and shove it into a "naked" AVR chip using avrdude, but the main thing that experimenting has left me with is an alternative to a working USB connection on my boards.

All I need is a six-pin header and I can plug in a USB adaptor I have. And after that, with some exceptions, I write Arduino-style code. The Arduino IDE is another piece of freeware. It is a bare-bones coding program, with essentially no advanced tools. But for the 8 KB of software I'm putting into a Holocron brain, it is enough. It's rather like the good old days of writing HTML pages in a text editor...

The main window of the Arduino code editor -- showing some very un-Arduino like code; these are direct register calls basically written in bog-standard C.

It took a few years to get all the pieces of this toolchain into place, but now I have it, doing electronics has largely moved for me from squinting at poorly-labeled parts, tacking them in place with random bits of colored wire and hoping, to a largely computer-aided process executed on the laptop.

Which is a lot like much of my props-making now. I'm making still-increasing use of laser cutting, which translates 2D CAD (actually, Illustrator -- and actually, I use the freeware Inkscape despite some ongoing file conversion woes) into precise cuts in the material. And 3d printing, naturellement.