Monday, June 29, 2015


I'm really starting to like Fusion360. At least, for parametric models. I have no idea what it looks like in mesh and whether the output would be useable in the Poserverse. One big one; unlike my usual mesh modeler (Carrara), booleans work great in Fusion. In fact, booleans are emphasized by the software.

So I'm making pretty good progress figuring out all the internal bits and pieces that hold the raygun together and put the electronic parts where they need to be:

As a little recap; this is a commission prop, with a firm due-date (now less than seven weeks away). The spec was a retro-looking raygun; "Jetsons, but as if it were real." Thus metal-body construction and exposed hardware.

After several weeks of sketches we hit on the right look:

The first thing I made was a paper mock-up, extrapolating from various gun-like objects I had around the house to scale the grip and body. That mock-up showed the dimensions needed a little more tweaking:

Next, to help visualize the thing, I made a second scale drawing, cut that drawing out of foam-core, and when the dimensions seemed decent, padded up the foam-core with expanded polystyrene:

Sanded down, smoothed out, painted silver, it gave me a good sanity check on the shape and I could let the client hold it and see how it looked on her. I made a few notations at this point for adjustment to some of the dimensions:

After that the project moved into CAD. More problems had to be solved within CAD, and I made several changes -- some of them accidental, such as the new direction of the grip texture. More emails back and forth. I also went to Urban Ore to look at old drills and similar tools to brush up on appropriate assembly details. But at last, the outer shape was set. This is a quick render from inside Fusion360:

And now the internals are getting finished up in the CAD -- this week I'll finally be able to start cutting metal:

And since the mock-up had been useful getting to this point, I spent a little time modifying it to reflect the new shape:

Don't mourn -- it will get all smoothed out again. (And next time I do something like this, it will be done with MDF and Bondo so it can take details properly and hold up to the rigors of casting or forming). The mock-up is better already; it is pink now:

Oh, yes. And I shipped the latest grenade order, bringing the total number of Aliens M40's I've made and sold to....44. Which would look something like this, if I still had any of them here:

Sunday, June 28, 2015

TechShop: Tool Data

TechShop does not believe in having a lot of information online. But neither do class handouts, or even Front Desk, make a good resource for when you want to know what kind of machine it is, what size materials it will handle, what tools fit, etc.

I'll likely come back and re-visit this entry frequently as I find out more. All data is for the San Francisco TechShop, and is current with my posting dates.

Vacuum Former: It is a Formech FM660, with a street price of $8,000 or so. It can handle sheets up to 26" x 26", with a forming window of 24.5" x 24.5", and up to 1/4" in thickness (thicknesses over 4 mm, however, are not recommended). Styrene (available at craft stores and in the form of "For Sale" signs at larger hardware stores), ABS (available at Tap Plastics), polycarbonate, extruded acrylic and PETG all work. TechShop carries pre-cut PETG (forms extremely well, food-safe, clear) at the front desk. I have only used PETG on this machine.

3D Printer: TechShop SF is currently down to ONE functional printer, a Type A Series 1, 2014 model with the metal frame (currently selling from Type A for $2,700). It can handle PLA, High Carbon PLA and PET filament and has a print volume of one cubic foot (12 x 12 x 12 dimensionally). It includes the CURA software that already has the printer's profiles built in. PLA filament in several colors is sold at the front desk at as low as $34 a roll.

Metal Lathe: TechShop SF currently has two Jet GH-1440W3 lathes (about $12,000 new), of which one is currently broken. The universal tool post appears to be a BXA, and the tool holders in shop can handle 3/8" tools. The lathe has a swing of 14" over the bed, 8.5" over the cross-slide, with 40" between centers. The gearbox can (apparently) handle metric and inch threads. It is an engine lathe with gear-driven horizontal and cross travel, with a manual compound rest on top of that. There is a Acu-Rite DRO (Wizard 411) that reads down to ten thousandths for horizontal and cross travel only.

Mill: There are two "Bridgeport" type mills from Jet, capable of handling steel. Model number appears to be JTM-4VS. A basic selection of well-used end mills are available at the check-out desk, as well as some smaller end mills (mostly suitable for the Tomach, below) sold at the front desk.

Laser Engraver: There are 4 Epilog lasers in the 60 watt range available, as well as two other lasers reserved for the really serious users. These appear to be the discontinued Epilog Helix (price around $24,000 with filtration system included). Bed is 24" x 18", a size that is also sold downstairs in 1/8" and 1/4" acrylic as well as laser-compatible (?) MDF. They can cut or engrave acrylic, most woods, rubber, delrin, styrene, paper, cardboard, and engrave some ceramic, stone, glass, and coated metals. They can not engrave raw metals or cut them at all, nor should they be used with foam-core, PVC, vinyl, expanded polystyrene, ABS, and several other materials. The shop does not recommend cutting anything thicker than 3/8". I have used acrylic and sheet styrene with good result.

CNC Mill: this is a Tormach PCNC 1100 (base price $8,400). It has a 1.5 HP motor, and the table is 34" x 9.5". The shop is strongly disinclined against cutting anything harder than aluminium, but it can (supposedly) handle a 1/2" end mill easily. Takes Mach 2/3 Arcs (inch) G-code, as well as G-code Arcs (inch) with the *.tap suffix. Cut3d, which includes a compiler for the above formats, is on the machines upstairs (as are several CAD and 3d programs, notably the complete suite from Autodesk). The front desk has ball nose and straight end mills for a very reasonable price, but the only aluminum are blanks suitable for carving injection molds.

Shopbot: The SF shop has three. First is a PRSalpha that can handle stock up to 4' x 8' x 6", with collets for 1/8", 1/4", 3/8" and 1/2" shank. They may be getting a better supply of bits to be sold from the counter. Soon.  They also have a "Buddy" (24" x 48", I think), and a desktop model with a 24" x 18" bed. The Alpha goes for over $17K new, and it whizzes through birch ply, cutting out a coaster in a minute or two. It can handle most woods and many plastics and composites.

Friday, June 26, 2015

The Amazon Effect spreads my "local" hardware store.

OSH has revamped their branch to be tighter organized by project, instead of the former organization by general category. This makes a certain sense in their desire to serve more DIY traffic; the hope is that someone will walk in saying "I want to put a new sink in the bathroom" and they will be directed to a part of the store that has everything to put a sink in, but only what it takes to put a sink in; no confusing options or related tools or parts.

This is of course entirely bogus for any project that can't be so easily categorized. And I don't just mean prop creation. What about if you are trying to repair an existing sink? What about if you are trying to put a sink into a non-standard room? What if you are trying to hook up one of the small on-demand water heaters that are getting increasingly popular? Or what if you are putting in a shower, but several of the parts are shared and usually found closer to the sink section?

Even my second favorite online electronics source -- Adafruit -- has succumbed to this. Their site is now primarily organized to require you to drill down by application. So are the LED driver chips in Cosplay, or in Arduino?

Not saying the reverse can't be an excess. Digikey offers everything, period. You drill down using consecutive booleans, and hope you didn't over-specify too early in the search (as in, limiting your parameters to switches in the 500ma range as you try to find smaller and smaller switches, without realizing the keyboard type switches you are looking for actually have a higher rating and thus are not showing up in your selection).

But you can do a two-tier system. Generalized search, paralleled by helpers. Amazon and Adafruit both do this...the problem is the lead-you-by-the-nose search is prioritized to the detriment of even basic functionality of the more open search. In Amazon's case, boolean search terms are largely broken and the filters are too open. And there are excessive pop-ups taking bandwidth from your computer and, more importantly, your own attention, each desperately hoping they've found the One True Box that you will then make lots of purchases from. Adafruit, unfortunately, takes the latter to an excess mostly due to the huge graphics and code load of their current pages. It is all but impossible to navigate their site with DSL now -- I need to go into the shop to use the ultra-fast connection there!

Philosophically... well, that is part of the process of learning anything. That is, learning the envelope, the parameters. How are things called? How are they categorized by the majority of users? You learn, over time, that a handsaw does wood, a hacksaw does metal, but both are hand tools. So if you want the latter, you look for hand tools but steer away from the obvious wood-working tools. In everything you attempt you find yourself needing to learn the names, the concepts, the implicit groupings; the territory.

You learn how the slag hammer is used when you learn to weld (stick, that is), and thus you know the name and shape of it and know it will probably be found with the wire brush and the sparkers, not with the mallets and the claw hammers. And this is true whether you are in a workshop or at a hardware store. Or in the Grainger catalog.

Sorting things by "Here is all you ever need to know in order to do one specific task" short-circuits this entire learning process. And to me, it is as bad -- as well as being all-too-similar -- to the Amazon urge to "Find me another book that is as identical as possible to the one I just finished reading, and don't open my mind to the wealth of other choices that are out there."

Thursday, June 25, 2015


I've been musing a little on POV in fiction. An important note; Orson Scott-Card has an excellent book called "Characters and Viewpoint" that covers this subject in more depth than I possibly can.

I did writing all backwards, of course. Wrote short stories. Wrote a novel. Shopped the novel. Then sat down and spent another ten years writing fanfic and, well, actually learning something.


I forked the CAD file, tried out several variations, emailed the client...and I think I've boiled down a little to a tweaked version that maintains things I liked about the prototype while still walking that line between maintaining that recognizable "Jetsons" ancestry but looking solid and practical:

I just can't get the insulator "donuts" any bigger without it feeling unbalanced. But the less busy fin and the longer "swoosh" and smaller dish are helping a lot, I think. I'm trying to keep some hints of 1950's propmaster here, but the "jewels" (marking intensity settings) were just a little too much in that direction. Besides...the unmarked dial means I can put any arbitrary number of behaviors into the software.

I keep wandering off into elaborate sidetracks, like the idea of a remove-able energy cell. As of the moment, I'm reserving the option but the access plate in the pistol butt is just going to be there to get at the USB charge cable. I'm also having a lot of trouble thinking in 2.5d.

Here's the thing; the majority of this is going to be run off on a CNC mill. I'm flipping parts once to do the back sides, but that means every cut I make has to be possible to reach from one side or the other. Took me forever to wrap my mind around how the catch for the butt plate works, until I finally saw that from the viewpoint of the mill, where the catch needs to go looks like a slot.

I have forty pages of sketches brainstorming the various mechanical details. But of course how they actually work out gets revealed in the CAD. The assembly details of the front don't look right in the CAD, for instance; the sketches had a more generous space for tapped holes. So I'm wobbling right now on a range all the way from woodruff keys to threading down to just throwing JB Weld in there and doing a friction fit.

The electromechanical components are all here now; medium surface transducer, lever (limit) switch, potentiometer with integral twist switch, 3W pink Cree. The metal (and acrylic) is here as well. Sigh. Always something -- a 3/8" acrylic rod would fit right in with minimal lathing necessary. But the acrylic I want isn't available in that diameter. So I need to lathe the length of the rod, which is again unexplored territory.

Doesn't help that I had a grenade order that got delayed by the unexpected dance show. I finally finished lathing them today. I'm ambivalent there as well. I have learned so much since the first orders, and on average the quality of the work continued to improve. But at the same time my patience for achieving that possible quality is slipping. I'm skipping more steps and going "good enough" more often than I should. Doesn't help that it took 10 hours over three different trips to the shop to make just four grenades -- for merely $160, as I was doing a bulk savings offer as long as the leftover metal from the last big order lasted.

Which is why I'm seriously considering another lighting hang in Mountain View, despite it being a three hour commute each way. I'm saving a big chunk now on my TechShop membership -- got a year membership at one go. But that means my cash is dropping down towards critical again.

But with seven weeks to go until drop-dead delivery date, I simply have to push aside my financial woes and move the raygun forward. At least the CAD is finally moving properly. With luck I'll be ready to start cutting metal by this weekend.

Wednesday, June 24, 2015

Raygun VII.II

The CAD has been fighting me. I always love tutorials from the people bankrolling the software; it is extremely rare when they openly admit they are only doing the kinds of shapes the software wants, and letting it make their design choices for them. A luxury I mostly do not have, as this project has proceeded through a careful series of pre-production sketches, concept models, and so on -- with client approval at each step.

In any case, the surface detailing is basically done. I've also been struggling -- pretty much, throughout the design process -- with balancing the sleek menace of a "real" looking weapon, with the kind of playful, puffed-up cartoony look we are after. I may have been looking at this model too long, but right now frankly I prefer the mock-up:

It has a sleeker feel to it. Some appears unavoidable consequences of the tooling up; the client requested the "donuts" be larger and more prominent, for instance (which felt like it required a larger dish as well). The setting knob has to be bigger in order to get fingers inside it (although I suppose I could use a knob with a knurled outer edge instead -- or even go with a chicken-head instead of the 1970's television dial style recessed disk). And the new direction of the cuts in the grip was an accident, but I think it looks better. It does, however, pull away from the strong horizontal flow of the prop.

Even the fin almost looks better as a flat slab, instead of the sculpted airplane tailfin I had originally envisioned.

But there's only seven weeks until delivery. That's already far short of my original target of having a month for the client to show it off and maybe inspire some friends to purchase their own. So I can no longer afford to do a lot of second-guessing. Including with the software; I have to accept the ways it is forcing the shapes to go and live with that.

Monday, June 22, 2015

Raygun VII.I

This project is scaring me. I'm tempted to bail on the all-metal version and switch to making a nice sculpt. CAD is going depressingly slow, and I am filled with concern about the extent of the unknowns in the process. 

Plus even though the CNC step is the big one, there is a good week of work in electronics and in the plastic parts, each.

So finally got the details cut into the pistol grip. On the surface, simple enough; create a spline, turn it into a pipe and use that as a tool to make a boolean cut. Except not, of course. I haven't found any shrink-wrap or surface following in Fusion3D yet -- only the ability to snap a point to an existing point or plane (which half the time ends up adding the point to the previous sketch or body or whatever.)

And the way that operations are supposed to stack in history...meaning you could edit the spline curve to correct the look of the cut...well, that didn't work. So I had to do the cuts by trial and error. And that was after sort of figuring out how the spline tools work (apparently there are at least two different edit modes. In one, constraints show up as icons that can be deleted. In the other, constraints do not display and the only way you can figure out if they are there is by toggling them on then toggling them off again. For every single selectable point.

The other mild success is I hooked up the 2.5 watt mono amp to the surface transducer, and taped it down to a nice solid chunk of machinery (a nautical clock I happen to own). And it was pleasingly loud, especially when I hit some natural resonances. Probably not loud enough to be impressive at a convention, but with luck this will work for the prop. I'm starting to get concerned about interior space, though. The transducer takes up a big chunk of space and there's not a large hole between where the trigger mechanism has to go and where the potentiometer is mounted for the knob.

Oh, yes. I also ordered pot, trigger switch, a rotary switch in case I change my mind...and the metal. Hopefully the CAD won't suddenly call for stock dimensions larger than I estimated.

Saturday, June 20, 2015

Followed by slightly less

I'm really liking the new Holocron shell design. I think I have a nice combination of box-corners and central gear that captures several recurring motifs and gives a proper Star Warsy sense. The "Sith" texture -- which I want to use subtly to break up the diffusion layer -- is going less well. Perhaps I should re-try my "Moorish circuitry" pattern, only much smaller in scale.

Oh, yes. And the Jedi Temple seems to have flaked on me. Haven't heard anything since I gave him a full kit to try out.

Tinkering with the fanfic but don't have a good idea how to approach the next chapter. I mean; I know the purpose of it and some of the business, but just walking into it bold doesn't feel right. I think I need to either back off with another vignette, or set it up with a bunch of atmospheric description. Or start in media res with them solving the next puzzle...I don't know.

As part of that, I'm reading up on Parsifal, Lazarus, of course Fisher King and Longinus, not to mention keeping an eye out for famous paintings or sculptures of any of the above that would have been known in Emperor Rudolph II's time. With sidelines into Jewish Esotericism, medieval alchemy, meteoric iron, First Dynasty Egypt, Red Mercury, Barringer Crater, etc., etc.

I have no scheduled work upcoming. Several companies that will probably hire me again, and a standing offer to come repair some cable at a rental house, but having no clear source of income in my future is making me all hermit-crab -- wanting to stay inside, not eat very much, and very much not spend any money. It is a hard emotional state to crawl out of.

Slightly productive day

Had a brief burst of productivity. Went to the bank, did laundry, mended clothes, took out the garbage, repaired my hand truck, paid bills, ordered materials, worked a bit on the fanfiction, and cleaned up my "clacker" mesh to make it printable.

On the latter, I smoothed the curves and closed off all the volumes. It is probably printable now. But there's more work to go to make it a hollow object with holes for bolts and functional handle and so forth.

The hand truck was simpler; the bearing on one wheel failed under load and the stuck wheel got hot enough to tear a hole in the plastic supports. So I drilled out a 3/8" hole in the supports, and seated a bronze bushing in a cylinder of aluminium I lathed down to make a replacement hub, and secured a bolt through the new bearing. Was the first time I used a boring bit on the lathe, too.

I've ordered most of the material and parts for the Raygun now. The CAD file still has a lot of work to go, though. Holocron is even further...finishing the Inkscape files won't take quite as long, but I need to drive across town for more acrylic stock. Pity. There's interest in a cheap holocron kit at the RPF. Unfortunately I'm also shooting for a unit price that is barely greater than cost.

And both projects look to need me to spend more time at my DuckNode. Which isn't just PCB layout time -- I need to pull out the breadboard and experiment to see how to enhance the stability of the circuit under full load.

Thursday, June 18, 2015

Dead Space : The Man Haunted By a Sharpie

Actually, the Black Marker (and Red Marker, and so on) are alien (?) artifacts, not drawing implements. But anyhow!

First off, like anyone who keeps an eye out for the $1.99 sales, I have a nice little Steam directory now. On a virtual drive, on my MacBook, accessed via Wine. As of the moment, the only non-Steam PC game I've played on this Mac is the free "Times" version of Tomb Raider.

So what works? My entirely unscientific, practically non-technical compilation of what ran pretty much out-of-the-box and what stalls or crashes on the loading screen, is:

Tomb Raider Anniversary: runs pretty much normally, controls can be a little twitchy but that's just the game. Sometimes have to toggle v-synch in order to stop the screen flicker.

Tomb Raider Legend: same as above. Did have a recurring glitch at the start of Kazakstan but finally cleared that up.

Tomb Raider Underworld: real-time water reflections slow things down a bit much and had to be turned off, but basically handles the graphics with good frame rate; also completed.

Tomb Raider 2013: have to take the graphics down several notches in some of the big set-pieces (pretty much anything around the shanty town) and some patches of texture render black. But then, there is a Mac version avail anyhow, which I'll even play one day.

Skyrim: game loads, and with a little tweaking the graphics look good and frame rate is quite playable. But no sounds play, and worse, the dialog box never pops up in play; meaning I'm stalled at the start of the adventure just before character creation.

Dead Space 2: fails to start, dropping back to Steam with a cryptic Windows warning pop-up (one of the ones that gives nothing but a hex code).

Bioshock: everything works fine, although the bloom+blur is so distracting I played a lot of it with the effects turned down or off.

Space Engineers: crashes back to the Steam browser when loading.

Fallout 3: locks up on the new game loading screen.

Black Mesa: frequent crashing but otherwise looks fabulous -- played through to the Xen portal.

Dead Space: everything plays flawlessly. More review below the fold:

The Magic Goes Awry

Just a random thought here: a term used of many modern fantasy stories is "Magic as technology." Aka, treating magic as a semi-rigorous science that leads to applied engineering. Among the most visible early permutations were those written by computer-literate people who played with the idea of magical spells as computer language.

(That said, the most clever and effective variation on this was Rich Cook's "Wiz" books, which explicitly took head-on the conceit that magic can never be made into an orderly technology by having his hero concentrate on very minor, simplistic spells which could be repeated successfully -- and then used computational tools to apply these minor effects over and over very, very fast and in large arrays. His hero could thus achieve the power of the large, complicated spells that took a lifetime of study to master, but achieve them with a script that any Script Kiddie could run.)

Anyhow...what I'd like to see tried is magic as real-world technology.  Too often it seems magical technology achieves all the conveniences of the developed world, but with fewer costs. Steampunk makes a similar mistake; steam technology in too many stories is cheap, clean, and efficient, capable of powered flight and the functional equivalent of television, and the environmental and social costs are downplayed to the extent that they have no real functional effect.

Well, there are writers who have flirted with it. "The Case of the Toxic Spell Dump" stands out, at least in title. And even old Bob Heinlein's "Magic, Inc." took a hard look at the potential costs of magic technology (making, it seems to me now, loose analogies to what at the time of writing was only a nascent nuclear power industry). And PTerry blazoned the way into the annoyance of consumer electronics and other modern inconveniences, achieved with appallingly simplistic magical tools (imps with paint brushes instead of digital cameras).

What I'm thinking, if my inchoate musings can be called that, is magic with all the costs and inconveniences of actual modern technology. Of a lack of standardized parts, of late-night service calls, of unexplained crashes, of fly-by-night third-world manufacturers, of DCMA.

It is easy to miss the solid functional and mature technology that underlies our daily lives; buildings that stand up and roofs that don't leak, electric lighting, indoor plumbing. And miss the way that, generally speaking, cars and lights and bridges and refrigeration work pretty durn well. It is perhaps too easy to concentrate on the leading edge; of consumer electronics, for instance, which delivers largely meaningless content wrapped in tedious confusion with a frosting of lies and failure.

Perhaps, indeed, it would be better to achieve the transport of people, goods, and services which so transform modern society, as well as the plumbing and lighting and so forth that made modern life in the developed world so different from that of most past societies, with some older technology, and reserve magic for an analog of the computer revolution. Because the Information Age and all its detritus is still new and experimental and not a little problematic, and the fruits of it are still fresh to many of us.

Thing of it is (something I tried to talk about in my Tomb Raider/SG1 fanfic, of all things!) it is very hard to rationalize a seriously schizo science and technology. If you understand metallurgy well enough to produce the bridges and railways and ships and cars that forever changed global society by making movement across the globe essentially trivial (whereas in a medieval village rare was the person who didn't live and die within a handful of miles of where they were born), then you by implication understand associated science, such as Maxwell's laws, and the technologies for long-range communication are within easy grasp.

I simply can't see achieving the quality of life of modern suburban living, from fresh fruit to off-the-rack clothing, without there being almost all of modern technology behind it, as well as modern society (if nothing else, you need the middle class of technical workers and artists and financial people to make it possible).

So, no, I don't know where to go with it. Just stuck down at the point where a character in a story is trying to repair a flying carpet, but the spell kit they have is all Latin and the carpet is all woven in Aramaic and the user's manual was apparently translated from French into Farsi, badly. And they could re-purpose the weft module from a pair of Seven-League Socks, except the Socks are under a EULA and all the physical spell components are potted, anyhow. And the service desk is trying to sell the new triple-decker carpets and First Tier support is a Golem physically unable to deviate from the script to give any useful advice.

Friday, June 12, 2015

Another Improvised Setup

Seems like a lot of theaters are asking for "A Sound Tech." I had one recently who asked for "A Light Board Operator," which was even more specific but just as wrong.

In the latter case, I got there only to find out I'd be setting the looks. Which is to say; I was the Lighting Designer on that show. Of course not getting the pay -- or the respect -- for designing the show, even if "designing" was constrained due to having to work within a Rep Plot.

Board Op is a trained monkey job. Literally; Ham the Space Chimp could handle sitting in a room with a headset on, pressing a single button over and over when told to.

Designing a show requires not just the expectations of being worth more or the mental preparation of having to do more than sit around doing crossword puzzles between cues, it requires being prepared. Packing a gear bag with such things as gel books and note paper, but also having the mental gear bag packed with the theater's inventory, manuals of the equipment, and oh yes, you probably should have read the script. Several times.

This is also true for sound.

Thing is, most of these groups just don't get it. They really think they can walk in, "plug a mic in" (because there must be a place to "plug mics in," right?) and then tell the tech (over headset!) how far to turn it up. Half the time, in these budget spaces, the gear is incomplete or broken anyway, and almost all the time it is so non-standard you are having to play archaeologist to figure out how it works.

Indeed. This latest gig, half the equipment was in storage and almost nothing was documented. With help from someone who did sound there last year I got it all set up and working. It sounded horrible. And fortunately I'd packed as Sound Engineer. Pack just full of cable testers, spare cable, adaptors, etc., etc. Even an RTA microphone. And, pretty much, everything else I could spare that wasn't being rented that same week to a graduation exercise across town.

So I got the system basically up, minimally acceptable, and hooked up the show needs as described. And with thirty minutes to go to rehearsal...the client finally found time to come back and tell me what they needed. Which was of course not what was on the paperwork, nor what the gear was set up for, or even what the gear supported.

For instance, they demanded an FOH position. I agreed, in principle...but the building wouldn't let us move the board. Fortunately (!) I just so happened to have anticipated something like this and had a Behringer baby board in my bags, along with an audio snake and a handful of turn-arounds.

Two shotguns. Four hand-helds. CD playback. And I had a Xenyx1002 with two mic preamps and 4 stereo ins. So right. Barely enough; use the stereo ins in mono mode -- fortunately the handhelds are Shure UR2's that can output at line level. Run the "CD" (rather, QLab on my laptop) direct, bypassing the board completely. The one single Aux bus sent up as monitor feed.

Ten minutes to go, and the client ambles back again and says, "So we need a lot of reverb for these dream moments we have." Err, right. The baby Behringer has internal FX but plugging into the Aux bypasses it. So...split the feed, with Left Main being "dry" and Right Main adding an arbitrary amount of monitor to the signal. So now I can control monitor level by panning my now mono output, and the FX bus is free. And the computer bypasses the Behringer so the backing tracks are still in stereo.

And, yes -- instead of the nice Allen&Heath I'm stuck with the ludicrous EQ options of the Xenyx, with no EQ at all on the handhelds. And no compression options either. Which could have been death. Fortunately, when we got into tech, it turned out the kind of vocal performance was okay with that. If they had been doing American Idol vocal stylings it would be impossible. But for relatively controlled spoken word it is working okay without any of the usual vocal conditioning tools.

So of course after rehearsal they drop a mention in a passing email that I need to come up with another stereo feed for the videographer.

Because all of these is nothing. You don't need any skill, you don't need to spend hours studying the manuals of weird vintage gear, and you certainly don't need to hump a pack of $2,000 of personal audio gear around on BART.

All you have to do is "plug in a mic" and then press a button when ordered to over headset. Ham the Space Chimp could do it easily. And you'd pay him in bananas.

Thursday, June 11, 2015

Fusion Cooking

So I'm officially behind on the Raygun. My target was to start cutting metal this week. Work showed up instead, good work -- did one morning gig hanging lights (actually, spent most of the time driving the scissor lift around) for a clean $100 in cash.

From the money from the most recent grenade order I dropped fifty on a new tool holder from Grizzly. It looks good, all solid (and very oily!) metal, but I've experienced some unusually soft steel before. Such as the bench vise I got from OSH that has disabused me from ever buying a vise from that store again.

But even taking all this into account the CAD is going terribly slow. Part of that is learning the software. The greater part is having to solve so many design issues. Metal is a bit unforgiving. I can make a few adjustments for poor fit-up or other errors, but it is slow work correcting mistakes made in metal. Metal is hard, slow to shape and requiring power tools to do so. And expensive. I really need to anticipate as many issues as possible and solve them before I start cutting metal.

It is engineering. It is a balancing act. Trying to balance aesthetics, strength, and manufacturability. Out of the many things you have to do to engineer something properly is to compensate for various sources of error. You design in steps that will catch and correct (such as my current M40 lathing scheme, which holds 4/1000 in reserve for a finishing pass; this picks up and corrects various places where tools like the knurl or the parting tool deform the grenade, throwing up ridges of excess metal behind them).

A subtler one is how I run a de-burr tool around the edge of the hole before inserting the button; this produces an expansion space for the metal to flow into when I crush the plug in with the press. In previous grenades, this edge was forced into the button pin, pinching it.

The other major tool in dealing with the inevitable errors in measurement, tool wobble, manufacturing variance, etc., is to not design around perfection in the first place. I really had this demonstrated for me during discussions of the Apollo Program and the absurd suggestion that "the landings" were faked in a film studio. One of the claims the believers in a hoax make is that the necessary positional accuracy of the original launch is impossible to achieve. The slightest fraction of a degree off at launch, they argue, and the spacecraft would be multiple kilometers off target by the time it reaches the Moon.

Which is why the NASA engineers -- like any engineers -- did no such thing. They simply pointed the spacecraft "good enough" to get within the circle of error of the next designed-in correction stage. One equivalent in design for assembly is you use a slot or an over-sized hole on the upper piece, so the bolt will still go in and hold everything properly even if there is some slop in machining or alignment. You don't design so the holes must be perfectly aligned...unless there are other design goals requiring it.

But this has to be of course designed in. Even at the simplest level, design for manufacture means you have to solve endless "duck, wolf, bag of grain" problems, where part C is bolted over the bolt holding part A to part B -- fixing the assembly order and making it impossible to place bolt holes for C on the inside of A.

My raygun nozzle is currently there. The reflector dish is CNC'd out of plate stock, top and bottom pass (which themselves brings up the question of how good my alignment will be). On the final pass I'll machine a hole all the way through, and push a lathed spindle through that. The acrylic nozzle goes inside that spindle and all the way into the gun to reach the Cree that illuminates it, and ends up supporting the front assembly.

After working on it off and on for over a week, and covering several pages of graph paper with mechanical sketches, I've figured out the connections and assembly order. The spindle is one-way (it has a lip) and will have a tapped hole in the side behind the dish which holds a screw pressing into the acrylic. The dish is pushed against the spindle from the other side by the pressure of the 3d-printed insulator rings -- which also are floating freely on the rod -- and the whole Dagwood Sandwich is pinned together by a second screw at the gun end. Which, since the front end of the gun tapers, is on the outside of the shell, and since the insulator rings are there, is accessed for tightening by a hole in the insulator rings that you can fit an allen key through.

There are a lot of alternatives I had to reject, and a lot of secondary considerations. Could machine the spindle as part of the dish but it would look better lathed. And take a lot more metal to machine from a single block of material. The dish can't be lathed (wrong kind of curves) but it can be lathe-polished. Which means the assembly is designed so I can put both parts together and chuck that in the lathe before removing a metal central rod and putting the acrylic in. In addition, any error in the length of any of these parts is adjusted for at the gun end, where the final retainer is.

And, yes, the acrylic is a failure point. But if I added metal -- well, extending the spindle to the gun is possible but the thickness is determined by the aesthetics at the nozzle end, and still creates a potential weak point. Inserting a stainless steel tube strengthens it, but requires the acrylic nozzle have a step to cover the diameter change, and that becomes the point of failure. This way, replacing the nozzle in case of breakage is less onerous, and I'll simply have to put up with the fact that the reflector dish provides a good lever to put stress on it.

(And, yes, I could switch to polycarb, but it is tougher to machine and although stronger, more likely to leave dangerous edges when it fails under stress.)

I've more-or-less solved the front assembly, how the handle fits together, the fin assembly, the trigger guard. But I still have to finish designing the trigger assembly, the access plate/removeable power cell that will allow uncoiling the USB cable to recharge the internal LiPo, how to get the LED wired into the fin...and I haven't even touched the side panels with their switch, indicator lights, and swoosh.

And very few of these assembly details are reflected in the CAD as of yet -- which I fully expect is going to reveal other potential problems in fit-up and assembly, as well as mechanical weaknesses and structures which are un-machinable as they stand. (I'm not about to get into 4-axis CNC at this point, so I basically have to make shapes that can be attacked from two sides at a maximum, plus traditional machining -- milling and drilling -- at off-axis to these. And, yes; every threaded hole I add is a manual operation; hand-tapping.)

Oh and yeah. My cheap eats these days is a three-day curry; 1 "can" Coconut Milk (I like the "school-lunch milk" boxes from Kara; very rich and fatty), red curry paste (May Ploy brand; comes in a tub like miso paste), tofu and veggies to suit (I get locally-made extra-firm tofu sold bulk-style at Berkeley Bowl). Often Dynasty sliced water chestnuts, cut baby corn -- but I've also used carrots, broccoli florets, canned bamboo shoots, and fresh snow peas. Plus a can of Albacore tuna if I can afford it. Makes three servings...I brew up 1-2 cups of jasmine rice in the rice cooker and re-heat the curry for a meal. Goes nice with a rooibos chai (also bought in the bulk produce section).

Friday, June 5, 2015

Purchasing Wireless?

I've been telling people to wait if they can until the dust settles. Well, the dust is pretty much settled. The FCC will be selling off the 600 band; even though the impact may not drift down to us until as late as 2018.

And the digital systems are starting to appear from name manufacturers, and we're almost over the hump of high prices and teething problems of new technologies. Within a few more years I expect digital will drop down in price to similar to what analog systems had been (they are cheaper to make, but the manufacturer can -- for at least the next few decades -- charge more for them because of the enhanced options.)

For the longest time I've been praising the Sennheiser packs. They are built like bricks (metal construction), you can cram 16 units into a frequency band, and they are fairly immune to anything but, well, Shure mics operated in their vicinity (not even on similar frequencies -- mid-range Shures seem to overmodulate and take a larger footprint than you would think).

The worst weakness of the Senny's is the connector to the element, but this is a weak point in all mics -- for me it is a toss-up between the locking mini of the Sennys and the TA4 of the Shures. One caveat; you need sound techs who pay attention and will screw the Senny's back down every now and then. If they do, the screw-on will outperform the TA4. If they don't -- the TA4 wins by default. Both can be aided greatly by added strain relief, done variously with tape and moleskin.

If you simply must go analog, the G3 series is still a no-brainer at the mid-range. If you have the bucks, then Shure UHF or one of the really high-end systems. If you are looking at 500-800 a channel, then the G3 at 600 bucks a channel outperforms the SLX and is (according to a rough weighting of the commentary threads at Control Booth) a bit ahead of the ULX.

For my mind, the Senny wins hand down for stage musicals; not because the ULX has a plastic case, but because it runs on (shudder) 9v. Those have less juice and cost more than AA, and are less common in rechargeables.

(As an aside, there's a chorus of people who crow constantly that rechargeables can never be used for stage musicals. Their reasons are three; that they can't be sure the battery got back in the charger every night, that there's no spare available if you do forget, and that the "gas gauge" gives a misleading reading. All of these are trivially wrong. For the last -- flip the internal switch to rechargeable and the meter will be accurate. For the other two...the critics are imagining a situation in which each mic has its own pair of batteries and there are exactly as many as there are mics. Yes; if you did this it would be a recipe for problems. So you don't. You treat the batteries in bulk and you have double the number, plus a margin. During a matinee, the evening's batteries are already in the charger, and between shows you swap them out.)

(And beside...if your crew is so lame they might forget the batteries, then why are you trusting them to check elements, mute switches, condoms, and otherwise make sure the mics are ready to go? This doesn't speak, to me, of problems with rechargeables. It speaks to a poor approach to prepping mics that is going to give you endless problems with broken elements and other technical issues. Popping in fresh batteries is mandatory no matter what you use, and it is only one of the checks each and every mic must see each and every performance).

Anyhow, the paradigm has changed. My recommendation if you must purchase microphones now is Shure ULX-D. These are 1.5 to 2x what you'd pay per channel for G3s, but they will get you 30 channels to a frequency band and will see you through the coming FCC sell-out.

Plus ethernet access is becoming more and more an essential tool. The G3 series 300 added this, and the 500s make it better, and the UHFs have it in spades. And of course the ULX-D; making full use of the digital channels comes with networked coordination and control.

I'll probably change my mind when I've had a chance to look over a Sennheiser digital, but right now the ULX looks to break the "if it has an X in the name, don't purchase it" rule for Shure mics.

Thursday, June 4, 2015

Project Analysis

The Space Helmet project is done.

The helmet is modded in entirely non-marring manner using variously hot glue and magnets. And just in case the explorers need to go somewhere that isn't a hard vacuum, they have a simple oxygen mask...

...that also fits the period pack and the new hose:

So why did it take longer than I expected -- or intended?

Well, one thing is the mask. Which turns out not have been particularly necessary, as fun as I thought it might be to do. The mask was my introduction to using vacuum forming as a regular part of my process, and as such entailed a bit of a learning curve.

The worthiness of this should perhaps be demonstrated by the way I easily included vacuum formed parts as the plan for the new oxygen canister (shown in previous post). I can now add that to the laser cutter and the lathe as useful time-saving tools that can be part of future build processes. Next up -- 3d printer (I've had the check-out class already), and Shop-Bot.

As another example of a mature technology, laser-cutting the insignia then hot-forming them in place went near flawlessly. I did spend a few days in thought before I realized that was the appropriate method, though...

The eyepieces were also a learning experience, as I'd never really done clear casting before. So time spent there in various attempts at carving and grinding raw acrylic stock, sculpting and casting various attempts in clear acrylic, sanding and polishing in an attempt to get optical clear.

There was also time spent during the project cycle working on the Holocron and ongoing M40 grenade orders, and the Raygun (which is now behind schedule). And working on fixing my hand truck so I can continue to cart rental audio equipment around and make enough money to afford to keep building props!

This week seems particularly rich with multiple research topics to chase down. I'm still reading up trying to find a good finish coat, holocron shapes, trigger design, spring design and how to temper spring steel, etc....

Wednesday, June 3, 2015

Space Helmet: almost complete

Does seem like a lot of work for so little to show:

That's all the parts (minus a few minor bits like d-rings for the pack, the previous version of the straps, etc.)

This is the thing they are all fitting into:

That is, as a reminder, a period supplementary oxygen system (the canisters shown are chemical gas generators) and a reproduction trench helmet. The intent is to turn it into a pulp-era "what we thought space suits would look like" helmet and life support pack.

The simplest tasks are often the hardest. The trench helmet has vision slits. We wanted to make it look at least sort of air-tight and that meant fitting acrylic lenses into the roughly-fabricated eye slits. Three attempts later I have a "good enough."

Greased the helmet up with vaseline as a release agent and pressed Apoxie Sculpt into the eye slit. When that was hardened, trimmed and sanded for a nice shape. Molded in the last of my silicone, using modeling clay as a mold box, and cast in "Easy-Cast" clear resin. 

Then realized the curvature was making them impossible to see through...used a Dremel sanding drum to curve the backs to match the fronts, then wet-sanded up through the grades; 220, 400, 800, 2000. Finished off by dipping in Future floor wax when Novus #2 failed to restore a good clear finish.

On the other hand, sometimes what looks complex is actually (relatively) easy:

The decorative emblems were laser-cut from 1/16" acrylic and some scrap styrene sheet, and supermagnets glued into a hole laser-cut for that purpose. A little spot putty and some texture paint (for the "well worn" versions) and they are ready for detail painting. Even the pattern was no headache; I took the Black Sun image off the Wikipedia page, did a "convert to vector" in Illustrator, and with just a few minutes of clean-up it was ready to laser.

The inlet there was mostly nasty due to having to grind a helmet-fitting curve into the original plumbing hardware I started with:

I found a selection of parts that had a nice look and fit the hose I was using. Used the Dremel to shape them, glued them together with JB Weld, filled in some remaining details with Apoxie Sculpt:

The original intent was to use a separate oxygen mask. As a reminder; the mask started with a duct-tape dummy of my own face, went through plaster positive mold, Sculpey sculpt, pull in PETG, added details in laser-cut acrylic, cast "beads" in acrylic, and plumbing fittings, with the rubber edge achieved by stripping a length of audio cable and slitting the cover to fit it over the edge of the vacuum-formed shell.

But the mask doesn't fit well under the helmet, so we're adding an inlet (that fits the same oxygen hose). The hose itself, by the way, is "universal" washing machine drainage hose spray-painted black then back-painted with grey primer to pick up the details. The coupling at the tank end was hand-fabricated out of ABS plumbing fittings, with tiny strips of styrene glued on to make the finger grips.

Of course, this being actual period Navy gear, we didn't want to take a chance on whatever chemistry was inside the original canisters. So fabricate a new one. Off to the grocery store with a pair of calipers.

Trimmed the can to the right height, fitted an MDF disk to keep it round and make the "top" lid, and filled with a mixture of plaster and crumpled expanded polystyrene (to keep the weight down). Then worked on the distinctive conical ends:

Marked out 1/8" MDF disks;

Cut them out on the scroll saw and glued the stack together. Fitted a short length of ABS pipe in the center and skinned the thing in Bondo. Then the usual round of primer, spot putty, final paint coat to make a vacuum former "buck." I need to find a different paint, though, plus something to use as a proper mold release.

(I would have lasered these out, but it wasn't convenient to run out to TechShop that day).

As usual, the buck didn't survive. But I got two good pulls from it which is all I needed.

Trimmed with metal shears then filled the vacuum formed shells with Bondo and put them on the top and bottom of the can.

When they had hardened, cut a narrow strip of scrap PETG (styrene would work just as well) and used a heat gun to convince it to curve nicely to simulate the metal fold at the top of the can. If I had been smart, I would have sanded it first. As it was, I wrapped tape around the can to protect it while I sanded the PETG down to make it look more like the rolled metal edge at the other end of the can.

And primed, it doesn't look too bad.

The rubber grommets started as a chunk of EVA foam from an old equipment case I had lying around; cut down to 6mm with a razor saw, then carefully cut out into the proper donuts.

All in all, the can is a little too heavy, but it is a decent match for the original, and is sturdy enough to stand being cranked into the pack:

(The insert canister doesn't need the protective end caps...or for the caps to project quite so far into the strong springs of the pack. It won't be getting weathered as these basically come out of the box and get discharged in a couple of hours. The green, however...John Deere green is not a perfect match for the yellow-green of the original equipment, but I'm not going to mix something and try to get a good brush finish so good enough).

Tuesday, June 2, 2015

The Wheel Came Off

...which added a little more grunt factor, but still hasn't slowed me down.

I've been doing great for several weeks now. I wake up before my computer does. My internal clock is pretty faithfully getting me up even when I set an alarm to some unusual (and early) time to get to one of the varied gigs of late.

Worked a shift down in Mountain View, which took about three hours to get to by Caltrain. Did my crazy budget show. Then a lighting hang for the ballet. Started with 12 hour days, went into fourteens; in four days I'd collected twenty hours in overtime alone. Which are not actually particularly long hours, not by theater or my standards, even without lunch or dinner breaks (although I did get up to fifteen minutes to quickly eat something). But over half of it was lighting, dragging heavy gear around and crawling up tall scary ladders and it was quite physically taxing.

Just finished a gig in The City, which while figuring out the buses I managed to get an average of two miles a day hiking up and down those famous San Francisco hills humping a bag full of laptop, audio adaptors, video adaptors, script, MIDI keyboard, test and repair tools, etc.

But that wasn't as bad as dragging two floor wedges and three wireless microphone sets (plus the usual cable and test gear and power supplies and so forth) on BART. Which is when I used a cheap dolly from Orchard Supply, which inevitably threw a wheel just as I got to the station.

I have no idea what cause and effect is, but I feel good at the same time I'm doing lots of physical work. And I'm also conscious that on those days I'm doing well, I'm eating less than I'd like, sleeping less than I'd like, and often being rather colder than I'd like (standing around near Fort Mason at night waiting for a bus....brrr!)

It is also possible my sense of physical well-being is tied pretty directly to my sense of financial...well, "slightly betterness." In a total reversal of the last decade or so, the last half dozen or more jobs have paid me more than was agreed to. This goes back to Nutcracker, who slipped me a cash bonus, a gift card, a bag of coffee and a bottle of wine in thanks for my work. Even the gig I'm on right now (a wee nothing of a children's theater at a really lovely masonic center in The City) is talking about adding a couple more bucks...if for nothing more than the loaner gear I humped out there on my broken dolly.

Now all I need is the time and concentration to build some of the props I'm contracted for!