Holocron history

This prop took forever. But there is reason for it. Basically, it isn't "a" prop. There wasn't a straight-forward design process from a base idea through a directed iterative exploration.

I was handed a kit to assemble and paint. I'd just been introduced to laser cutting and engraving, though, and I thought I could pimp it up a little.

The experiments worked. Well enough I ended up documenting the project for Instructables. And that's where the trouble started.

Enough people at Instructables showed an interest that I made my files available. Since some of the parts weren't originally mine, I had to come up with designs for those, as well.


It was through Instructables that I was contacted by the master of a Jedi Temple, wanting a custom design made for his students. I agreed to work on it. Many emails and iterations and a full free kit shipped out no charge and I stopped being able to shake the feeling that he wasn't actually going to be good for the cost of the final kits. So I parted ways with that customer.

Since I now had a new and tested shell design I tried for a while to generate a new holocron based around it. But I didn't like (and still don't like) and of the results.

The holocron does not yet appear in any movie. It appears in some games and animations; one appearance being the best documented appearance I've been able to find. This natural goal was blocked, however, by the seeming impossibility of achieving it with the materials at hand. So I continued tinkering with other alternate designs, trying to fold in various motifs from the Star Wars universe.

It was at that juncture that I opened an interest thread at the Replica Props Forum. I got strong interest there, but still couldn't satisfy myself with the design.

Took a break to work on other projects. Did the Retro Raygun, some other things. My Croft necklace was also a hit, and I gave it away on long-term loan, which led me to starting the Wraith Stone project, and that looked to require some advanced electronics, so I picked up the holocron project again just to be able to work out the charge circuit and load sharing and surface-mount issues on a simpler board than what I intended for the Wraith Stone.

And when I returned to the holocron, what I had seen as an unsolvable problem turned out to be trivial. The critical insight might have been a function introduced on the new lasers just installed at TechShop; vector engraving. In any case, I immediately moved to front position a design much more closely based on that one animation.

It is just different enough from my first holocron, though, that the lighting didn't look right anymore. So back to some very basic development to rethink how the lighting circuit interacts.

And, of course, late in the day I realized there were possible ways to get it to look even more like my selected source. The very first holocron was a three-layer model; painted shell, solid diffusion layer, then the vector-cut "circuit" layer. I finally broke through this paradigm -- first through having to add a diffusor cube, then through realizing an inner "hypercube" might be an even closer match to what was seen on screen.

And that's where I am right now; cutting out yet more test pieces to see if this idea works out, while my growing list of confirmed customers are demanding I let them give me money...

Which is of course the absolutely perfect time for a major change at my day job.

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.

Buffing Stats

I'm walking every day. Also went to the gym monday, and intend to return to going regularly.

Still listening to a lot of history and archaeology (and watching videos, historically-themed movies, reading blog posts and a few reports and papers, even). That's also consuming an hour or so every day.

Taking multi-vitamins and switched to fruits and grains for lunch and upped the veggies and fruits part of my diet. I don't have a lot of middle-age spread but I would like to see less of it anyhow.

(Also learning to drink beer again, after going a decade dry. If I'm going to be hanging out at a pub once a week, I would like to be able to be properly social.)

However, I've let my violin practice slip. I was getting 20-30 minutes a day in, and had reached the point where I could comfortably and productively practice for longer at a stretch. But between work, workout, and weather, and pushing on getting product out to customers who have been waiting far too long, there just aren't enough hours left.

Way Hot

The delightful image above is from a lightweight but not completely horrible 1993 version of the venerable Journey to the Center of the Earth; another failed series opener released as a stand-alone TV special. It is much, more more Pelucidar than it is anything from Verne, but anyhow.

Weather is starting to cool but I'm walking to work. I'll see how long I can take this. Come the first of October, my boss is going to talk to his bosses about trying to get me a raise to something a wee bit higher than the new minimum wage.

The holocircuit has passed all tests.

Even with a mere 150 mAh lithium polymer cell I got seven and a half hours at the nominal/bright setting. That's plenty long enough. Unfortunately I'm down to scraps of acrylic...and Tap Plastics is inconvenient to public transit.

(No inconvenient to get to, per se. But inconvenient to get back from while holding unwieldy sheets of material that is quite capable of giving you nasty cuts. Bad enough riding BART with the things. Walking a mile in the heat with them is an experience I'm not longing to repeat).

Upson Downs

I have orders (not yet confirmed) for over a thousand bucks worth of holocrons, and a microphone rental in the last stages of negotiation. But on the flip side, I ordered enough electronics parts for the first holocron run all at once, and paid a bunch of bills forward. So of course at the moment my account is at its lowest (barely enough to cover rent) -- the brakes blow out on my car.

I'm still pissed that I haven't gotten full time or a raise after what is now thirteen months. I'm waiting another week before I raise the subject yet again; that's when the new minimum wage goes into effect in this (rather expensive) town.

Well, the upside to not being able to afford the repair for several weeks is that I could use the exercise. Oddly enough, I finally risked my healing hand at the gym today. It seemed to pull through without getting any worse. (On the other hand, I was climbing worse than I have in a decade...could barely haul through V2's)

Yesterday was dangerously hot. I sat around with the lights out drinking Icelandic "Arctic" Pale Ale and writing quick software hacks to test the last components of the Holocron circuit. When I broke for early dinner (take out from the market) I found myself oddly tuned to conversation. Of course. Trying to put my mind in software space, and it wants to be in dialog-writing space. So took a break with...a Laundry-verse book. Dialog and programming!

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.

Holocron N

The new boards arrived early; I didn't expect them until Monday.

I did make one mistake with my parts orders; I got some 100 ohm resistors instead of the 100K I needed. Hopefully I can compensate. Just got done placing components one by one on the first assembly and it is in the T-962 right now.

And, so far, so good. Had a bad hour or so when the neopixel didn't respond, but after splicing it into a previous circuit board to test it, realized the problem might be with the fuse setting on the AVR. Which it proved -- and thank you, since version 1.0 of the Arduino IDE you can burn those fuses automagically from the console. But I'll get some sleep before I test the charge circuit.

Yesterday I lasered again, mostly re-designing the internal diffusion cube to work better with the circuit board. If it all works I should be able to finally assemble a complete prototype with proper lighting (diffusion cube test, with an ad-hoc light source propped inside, in the picture below):

The sales thread at the RPF is started now and I've had eight requests for a fully assembled model. I have promised to show how some of the alternates look before I take the orders, though. Last night I also lasered out a partial set of the new "Sentinel" diffusion pattern (that's a Jedi symbol surrounded by a "koan" in Aurabesh). I didn't have a chance to cut circuitry, though, nor have I finished either the "Steampunk" circuitry design or the final of three planned diffusion patterns (which I'm calling the "Guardian" pattern publicly, but it is mostly inspired by Doctor Who.)

I also have to tweak the programming. That will take a bit. One depressing thing I've discovered is after all that tweaking for best possible fit, the width of the cut (and the resulting tightness of fit) is largely dependent on how the laser is feeling that day.



I also have to fill a promise to a very patient lad in Germany for a couple Pulse Rifle grenades and some rounds to go with them. I have a half-dozen bodies from my last run, just awaiting the buttons to be installed. Which is a full four-hour slot on the lathe and precision work, which is why I haven't felt up to it yet. The rounds I'll make a try at doing on the M3d but I'm worried about the quality.

This is more fully-assembled holocrons than I had hoped to have to build. I need to clean up the work area and assembly-line them. But now that the holocron is mostly a solved problem, I can move on to the next props projects. My feeling is, the priority projects now are two; a Morrow Project laser for my friend;

And a Wraith Stone for me. The former may be a great excuse for traditional prop building -- to get away from the machining and CAD and so forth I've been doing lately, and get back for at least a little to balsa and paint.

The latter combines several technologies. I dived back into the Holocron as a "simpler" project to learn surface-mount electronics and Lithium Polymer charge circuits. The Wraith Stone is going to require both:

My intention is also to carve it in semi-traditional style -- MDF, Apoxie Sculpt, etc. -- but then to scan it, print it, then cast it in order to achieve the kind of detail level and materials qualities I want.

Pity no-one else expressed an interest in the Retro Raygun, though. I still need to take it back and swap out the speaker and LED for more powerful models, but otherwise any concern I may have had about keeping the working files is fast ebbing.

(And when I borrow it back, I'm also going to take some proper pictures!)