How to Build a Halo Master Chef Costume

No, that’s not a typo. This year I built my son a Halo Master Chef costume for Halloween. I love making Halloween costumes. They’re usually a wonderful excuse to do some sewing and pattern design. When my son asked to be “A Halo Spartan,” I knew I was in for a different kind of build. People who build Halo armor (There are more than you think!) often use a program called Pepakura to decompose 3-D models into paper cutouts. There’s a free viewer, and the full program is only $40. A few years ago, I built my son a Boba Fett helmet using Pepakura, and I’d already developed a system for outputting the designs and cutting them out of card stock using a laser cutter. There was still a lot of tedious gluing, but I could cut all the pieces out and perforate the fold lines, which makes it quite a bit quicker to assemble. I started building this set of armor mostly because the author had done a good job of providing the files and a spreadsheet to help you scale the costume parts.

Pioneer Ready for Night PatrolOne of the big issues with Pepakura builds is that you really want the scale to be correct. After gluing 200 pieces together is not the best time to figure out that your scale is off. I think if I were doing a Pepakura deconstruction, I’d provide two versions of the model. A super simple rough draft with only about 10 pieces that would have the basic shape and let you adjust the size, and then a fully detailed version for the complete build. I didn’t really have time to do that. Lots of folks spend a year building their armor, and I was only going to have a couple of weeks. So I downloaded the files, fiddled with the scales, laid out the parts for 24″x14″ card stock that could fit in the laser, and exported the vectors into Illustrator. The vectors already have styles to show mountain VS valley folds, but you have to adjust the spacing to work better on the laser. You don’t want the card stock to get too weak at the fold lines, so no long dashes. I used .4pt dots and 2.5pt spaces for valley folds and 1/2.83/.25/2.83 pt for mountain folds. You can use Select -> Same -> Appearance to select all the mountain/valley/cut lines and adjust them all at once.

Card stock in the laserWhen I laser cut the parts, I used 2′ x 2′ card stock purchased from Michael’s for $.75 a sheet. I cut each big sheet in half to make two. Because I’m not printing on the paper, I can’t include any of the edge alignment numbers. I had to keep all the parts organized in some way, so I used blue masking tape to hold the parts in their original cut positions, and just kept all the pages in a folder made from one of the card stock sheets. Then I had to use Pepakura to look up where each piece was in the cut sheets. It was a bit like doing a puzzle.  The torso has 200 parts on 6 sheets, and it was important that none of them went wandering off. Blue masking tape is very forgiving and can be pulled off without damaging the card stock. Don’t use normal masking tape, or you’ll be tearing your parts and then your hair out along with some gnashing of teeth.

Glueing SetupI used Elmer’s white glue for the gluing. It’s great for this task because it has a long enough working time to let you get things into position and holds well. The one down side is you sometimes have to hold things in position for 30 seconds or so in order to have it start to hold. I modified a few clothes pins by sawing off the tips, making them into more nimble paper-pinching helpers.

 

Modified Cloaths PinsThe clothes pins were super useful for holding paper edges together long enough for the glue to set. Because I was using pre-perforated folds, I mostly didn’t have to crease the fold lines, and the few that I did crease I could do freehand with a bone folder following the connect-the-dots style along the fold lines. I only did this on a handful of folds. All the others could just be done freehand thanks to the perforations.

 

bicep Back LitBicep On White CounterArm On White CounterThe laser cutting took about 2 minutes for cut lines and 6 minutes for the dotted lines. The cutter is stupid about the short segments in those perforated lines, so it actually cuts them significantly more slowly than the normal cut lines. Laser time was maybe 10 mins per page, including setup and taping after cutting. The torso was 6 sheets, so it took almost a full hour to cut, but I can only imagine the amount of time saved. How long did the gluing take? I spent a weekend gluing up two biceps and a forearm. I had started a new audio book and listened to it while I was working, so I unintentionally timed my gluing. It took 13 hours 45 minutes for those three pieces. They have about 45 segments each.

Bicep Fully PaintedWhen I started, I told my son I wasn’t making any leg pieces or the helmet. I didn’t have enough time to build a full suit and the helmet and legs seemed like the pieces he wouldn’t be able to wear for trick-or-treating anyway. Partway though the build, he told me he actually wanted to be not just any Halo Spartan, but the Master Chief. I told him I couldn’t swap armor types at that late date, but I could paint it in the Master Chief color scheme. We were joking that maybe instead of a Master Chief he could go as a Halo Master Chef, and he could have a chef’s hat and apron instead of a helmet and leggings. Pioneer loved the idea, and that’s how the Halo Master Chef project was born. After rejecting ideas like the “Gravity Ladle,” we finally decided that the rolling pin was the funniest of the weapon options.

Torso All Glued Just PaperOnce the paper shell was done, I decided to back the paper with hot glue. Many people use fiberglass for strength, but that seemed way too slow, messy, and toxic for something he was going to outgrow in a few months. Hot glue is deeply wonderful for doing this sort of thing. Just squirt it in with the gun and let gravity pull it into an even coating. Keep drizzling more hot glue at the front of the downward sliding wave of glue, and it just works.

Torso Inside

Torso Filled With Hot GlueWhen you have thick glue, it can take several minutes to fully cool and set. This long setting time along with the need to re-enforce all sides of various openings forces you to glue it in stages. You need to let each stage cool before working on the next side. Tilt things so the glue moves the right way and dams up in the places you want. You can also use things like a straight piece of wood to position edges so they cool flat instead of bulging, etc. It’s very quick, especially compared to fiberglass. I was able to hot glue all the arm pieces in a single evening. After that, the parts are quite tough. There was one casualty of this process. After pushing several pounds of glue though my trusty (but cheap) hot glue gun, my impatient squeezing finally drove the heating element right out of the front of the gun. I guess it’s time to try a slightly more upscale gun.

Customized Neck OpeningThe torso is kind of a strange shape, and it was really hard to tell if it was going to be the right scale. I knew I’d have to modify the neck hole because it simply was too narrow for my son’s neck. I did some freehand paper design with card stock to make the neck hole bigger. After that had been re-enforced with hot glue, I had to hold my breath and cut open the entire torso with a hobby knife. I still didn’t know if my son would really be able to get into the torso. I even bought a longer chef’s apron in case he couldn’t get the torso piece on. I was worried I’d have to hack some bigger arm holes or perform other violence to make it work. Thankfully, we were able to get it on him. *phew*

Getting the torso armor off and on was a bit of a squeeze, but it worked. The only down side was that part of the front panel has to flex a bit to be able to open the back, which puts some wrinkle marks on the most visible part of the suit. I hot glued a magnet in the upper corner of the suit to hold that in alignment, and I also added two Velcro straps. I think it would have been nicer to have pairs of rare earth magnets all along the seam, so it all would get held in perfect alignment, but those magnets would need to have some sort of holding ring to give them enough surface area for the glue. I didn’t have time to figure that out or order special magnets, so Velcro was an easy on-hand solution.

I painted all the parts with primer then applied coats of army green. I masked the neck and arm areas of the torso and painted them black. After that, it was time to hand paint a bunch of dirt and grunge and a dry brush silver paint on various high points and projections to make it look as if the original paint had scraped off to show the metal underneath.

laserCutBlueMaskingTapeTorso Masked For NumberstorsoDoneExceptForDetailPaint

I laser cut some blue masking tape so I could spray paint the identifying numbers on the torso. I used 051 which is a nod to my namesake Kurt (Ambrose). I also put a black laser cut UNSC Eagle on. I finished Pioneer’s torso detailing the night before Halloween, and it was all ready to wear to school. I was surprised how well the suit held up. Paint was scraped off all the way down to the paper on some of the joints where the arm pieces rubbed against the torso, but in general it still looked good after a day and a night of candy-fueled revelry. We added a black sock as padding around the neck, but that was pretty much the only game-day alteration. Thankfully, the whole rig is still pretty light. I thought he would be less mobile with that rig on, but it wasn’t that bad. He could even ride in the car and use the seat belt without any problem.

masterChef1masterChef3

masterChef2

masterChef4

masterChefInCockpit

I’m going to mark this one down as a success.  I have a video of the Master Chef looking tough on Halloween Morning.

 

 

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Make Time Lapse Candle Videos

Timing a Birthday CandleWhile waiting for my project’s Printed Circuit Boards to arrive, I decided I should try shooting some more time lapses.  I won’t be able to design the iPhone software until I get some more experience.  I wanted to figure out some sort of time lapse that wasn’t crazy long.  That way I wouldn’t have to worry as much about ambient light changes, and I could try out different things quickly. I picked up a pack of birthday candles at the super market.  How long does it take one of those puppies to burn down?

I timed one, and it came in around 15 minutes.  Perfect.  Now all I needed was a better background.  As nice as peg board and cobwebs are, they weren’t the best back drop for my first time lapse, so this time I went that extra mile. I put a rusty steel plate behind the scene, but I still had to cover the base of a lamp. I decided to use a lovely wooden cutting board that my uncle had made for us. Alright, the stage is set. I completed my first candle time lapse.  That one went ok.  I was pleased by how the spirals on the candle sides make them look a bit like the tops are spinning down.

Blue Candle Lost SequenceThe one downside to shooting time lapses involving fire is that you must have a fire extinguisher handy and keep an eye on them the whole time.  None of this “set it off and go to bed” crystal growing luxury. One mistake I made was that I lit the candle with a match and accidentally clonked the candle while I was doing it.  For my next shot, I wanted to set up a bunch of candles and light them incrementally.  I rushed to the corner store and bought one of those butane BBQ lighters.  Now I was ready.  My first shot had been a bit short because the candle didn’t burn all the way down before the preprogrammed time lapse ended.  I guess my 15 minute test included a little bit of me blowing on the candle, which really shortens the burning time because it melts extra wax.  Also, this time I was going to be lighting them incrementally.  Best not to have it run too short, so I switched to a 28-minute duration.  I used the stopwatch on my phone so I could light the candles in 30-second increments.

I really like the idea of performance time lapse.  It’s kind of fun dodging in and out of scene between camera shots.  After 28 minutes of watching the candles burn, I rushed inside to squeeze all those stills into a movie.  OH NO!  This time there were no frames on the SD card. I’d wasted the entire shoot. What happened?  I still don’t really know. I’m using CHDK so my camera now has about 8 zillion tiny menu options, and eventually I just reset everything and re-enabled the USB remote feature.  Then it worked again.  It was so weird because during the entire shoot it was acting as if it were taking pictures.  Now I know to really watch the “remaining frames” number and make sure it’s actually going down.

Red Candle Disaster Waiting to UnfoldI did two more shots: a green one and a red one.   For the last shot, I  propped the camera rig up with some clothes pins on top of an empty cardboard box so I could have a shot looking down on the candles.

The Mystical Garden Poltergeist Wreaks Havoc

I sat with the camera until all the candles were out, and then I left.  When I came back, I found that the camera had flopped forward and done a face plant on the rocks!  In a panic, I tested the camera, but it seemed to be working.  While looking at the time lapse frames, I noticed that at the frame where everything went wrong the words “Mystical Garden” were eerily smeared across the rock.  Was the ghost of my previous time lapse jealously haunting the set?  No, but almost as miraculously, the camera shutter had been open during the exact moment of  collapse and had taken a smeary photo of the nearby box my crystal growing set had come in!

fallingCameraPhoto

 

I hear by swear off the Cardboard Box and Clothes Pin Mounting System.  Time to build a tripod mount and lay this Mystical Garden to rest. You can see all the candle time lapses here.

Building an Arduino based Motorized Camera Rig

I’ve always wanted to make a time lapse video. It’s like building a machine to catapult forward in time.  What could be more fun?  I really feel like the best time lapse videos integrate camera motion to give the scene an additional compelling dimension. I spent a couple of evenings building a quick and dirty motorized camera slide from a dead inkjet printer. It was a failure.  It was unable to produce the slow steady motion needed for video, much less the kind of control needed for time lapse.  I started to think about what a serious system with substantial time investment would have.  It could be bigger and have at least two-axis camera motion.  It would need a bunch of software with some way of key-framing the camera motion, maybe an LCD display, maybe a pendant control for stepping/snapping frames without jiggling the camera.  What else?  A way to power and auto-trigger the camera for time lapse.  All in all a much, MUCH bigger project.  OK, if that’s the end goal, what’s a good first step? I’m always wary of  physically big projects. As the size goes up, costs go up. Big projects are harder to get into/out of the car, take up more workbench space, and ultimately collect dust in a bigger way.   If I can fit a project into a single project box, life is simpler.

Bigger Motor ControllerSo instead of embarking on a large two- or three-axis rig, I decided to build a very small one-axis rig.  Heck, I already had a small one-axis slide.  This way I could get my feet wet with the software, LCD, motor controllers, and all the other fun stuff, but without as much schlepping. A friend of mine pointed out that a little motorized stage like that could also be used for focus stacking, and he’d been wanting to build a focus stacking rig.   He sent me little linear slide with a stepper motor drive and a tiny ball screw.  I’d never seen a ball screw that small!   It was sweet!  I poked around on Amazon and ordered a A4988-based stepper motor driver the size of a postage stamp.  They were cheap, small, and the data sheet made them sound like they were doing a decent job with the microstepping, which might be useful for very precise focus stacking.  I used to build stepper motor drivers out of discrete components, but it’s unbelievable what you can get these days for not much money. I’ve been itching to try some of the pre-made ones out, so I ordered the stepper motor and a much bigger driver board based on the TB6560, mostly because I was having trouble convincing myself that a driver without a heat sink was really going to be able to do the job. And even the big one was cheap.  It was less than $17,  including two-day shipping to my door. I’d also been wanting to play with some of these cheap LCD displays I see around, so I ordered a 4-line 20-character blue one that Amazon Primed its way to my house for $16. I ordered the blue one because a green-and-black LCD was going to make the project look like it was from the early 90’s.  I ordered one that had an I2C daughter board because I wasn’t sure how many IO pins this project was going to need, and I didn’t really want to burn half of them driving the display. When the display came, I was bummed that they’d shipped me the green and black version, not the blue one!   I set my time machine for the early 90’s and kept moving.  I wired up the display to an Arduino Uno.  I downloaded the Arduino IDE and a library to drive the display.  I wired it up like this:

Screen Shot 2014-04-23 at 8.44.48 PM

Then I ran this exciting bit of code.

#include <Wire.h> 
#include <LiquidCrystal_I2C.h>

//Addr: 0x3F, 20 chars & 4 lines
LiquidCrystal_I2C lcd(0x3F,20,4);

void setup()
{
 lcd.init(); 
 lcd.backlight();
 lcd.setCursor(0, 0);
 lcd.print("Hello World");
}

void loop()
{
}

Two DisplaysThankfully, it just worked.  The text was super crisp and readable.

I was still a bit bummed about the color, so I decided to roll the dice and try ordering the blue display again.  I’d be able to compare the two colors side-by-side and see which one I liked best. This time I did get the blue one. It worked and was crisp and clear.  Our eyes don’t like focusing on dark blue things though, and if I had to be brutally honest I’d have to say that the green display was more readable.  I decided to switch to the blue one anyway.

Special CharactersI wrote a little program to page through all 256 characters that could be sent to the display to see what sorts of special characters might be available.  There were a few useful ones like left and right arrows, the deg symbol, and a solid block character which I might actually use in my interface.

The next step was to put the various parts I was thinking about using together to visualize how things were going to fit.

Component Layout And Sizing

I was originally going to mount everything to the side of the motorized stage so I could cut down on external wiring.  I could even put the end-of-travel sensors inside the project box.  But it was starting to look 10 pounds of project in a 5-lb bag.

The project box was big, and it was going to have to be right under the camera or using it would be uncomfortable and trying to manipulating it would jiggle the camera.  Those issues seemed like deal breakers.  The next plan was to put the control box at some distance from the motor and make a separate control pendant that could plug in.  I’d need OK and Cancel buttons and some sort of spring-loaded pot for jog control.

Remote Jog WheelI went poking around at the local surplus store and scored a VCR remote with a nice spring-loaded jog wheel.  It even had two buttons inside the wheel, so I thought my control pendant problems where over.  I’d wire up the jog wheel/buttons through a phone connector to the main control box, and I’d be all set.  However, when I dissected the remote, I found that the jog wheel was not a pot.  It had 3 digital pins providing gray code position info.  That meant only a few jog speeds in each direction, and it meant I’d need more lines than a standard phone cord.  Back to square one.

Spring Return PotI decided to take a stab at adding my own spring to a pot to make a “return to center” jog controller.  I drilled a hole through the pot’s shaft and bent up a spring.  It worked. After some fiddling, I was able to make it control the motion of the slide.  It had a really sloppy feel to it. The center was always just kind of approximate, and it was harder to turn in one direction than the other.  Kind of a cruddy experience compared to the feel of the remote’s nice jog wheel.  I decided to punt for a while and work on other parts of the project.

End of Travel SensorsI wired up the end-of-travel sensors.  I was using IR gap sensors for a no-contact way of measuring the travel.  Now that the sensors couldn’t be mounted inside the project box, I decided to make them fit inside a bit of metal wiremold that I had lying around.  I used some Bondo to hold the sensors at the correct height and support a phone jack at the end so the sensors could be easily connected up.

This was by far the most annoying part of the entire build.  The phone jacks turned out to be back-stabbing fiends.  Fitting everything in the wiremold was annoying, and I had a wire tear out when I was closing it up.  Then the sensors weren’t working, so I ripped everything apart trying to figure out why. I had accidentally grabbed a two-conductor phone cord even though I’d  purchased a 4-conductor one. Then when I finally figured that out, I failed to realize that when using phone connectors, the wires get flipped from left to right so red on one end becomes green on the other, and black becomes yellow.  *Smack Forehead*  After I figured that out, I thought I was home free, but it still didn’t work.  I finally traced the problem to a poorly designed jack where the connector could clip in, but was still not fully seated and wasn’t making contact.  After that got resolved, everything was fine. But I’d burned an entire afternoon trying to run 4 wires a few feet.

Quick Release Plate MountedI got a super cheap quick-release plate.  When I was taking it out of the packaging, a spring and pin fell right out of the bottom.  I deemed them to be unnecessary and threw them out.  Then I noticed that  the cam lock tends to slowly unscrew and the screw can’t actually be tightened properly without making the cam hard to turn.   A dab of Loctite could solve that.  Hey, it was cheap!  My only regret is that I wasn’t able to mount it so the cam stuck out the same side as the wiremold.  This would have made the whole thing more compact left to right, but that might have required tapping some blind holes, and this way around it was simple to mount.  Just a 1/4-20 though an already existing hole in the carriage.

LCD Rig Wire MessI had all this wired up to an Arduino Nano.  It could jog the motor when I twisted the pot, and it could read the end-of-travel sensors.  Next was to start designing some UI for the LCD.  I played around with being able to highlight various menu options by quickly toggling the solid block character behind them, etc.  It all seemed doable, but it was kind of tedious Arduino development. I kept thinking “How is this going to scale up for multi-axis key frame animation craziness?”

 Massive Feature Creep Occurs

It was then that I noticed Bluetooth LE boards for the Arduino.  Could I control my whole rig from an iPhone app? I could ditch the LCD, buttons, pendants, and all the associated wires and connectors.  I could make the project box smaller.  I could write an iPhone app to do the interface heavy lifting, and I’d only have to do a moderate amount of stuff on the Arduino end of things.  No more planning out of awkward LCD interfaces.  Plus, it just sounded fun!

Blue Tooth ConnectedSo I ordered one of the boards, and I was off to the races. Adafruit’s page about wiring up the board is very clear, and I hooked up an Arduino UNO just to try it out.  I was able to get their UART echo communication going right away.  Simple, Pimple.

The next test would be to write my own program to establish the Bluetooth communications and see if I could use a slider to jog the motor.  I wanted to test the latency and to see if stepper motor switching noise would affect the communications.

The great thing about Bluetooth LE is that you don’t need any special licensing.  I spent one of my precious Wednesday nights ripping the com parts out of the Adafruit example and sticking them into my own simple app.  The app just had a connect/disconnect button, a connection status indicator, and two end-of-travel indicators. The communication is only 9600 baud, so I made a special jog loop the Arduino could go into where the phone would keep sending single bytes of  jog slider info, and a 0 would indicate that the jog portion was done and go back to the main loop.

The very first version wasn’t wired to anything. It would just indicate end-of-travel limits having been reached if you slid the slider close to the end of its travel path.  After tracking down an issue with a rough signed char, I got it working. The latency was quite low.

Jog Actually WorkingNext up: rewire the Nano to remove the LCD/knob and wire in the Bluetooth LE board.  Then I’d be able to jog an actual motor. I powered it up and could hear the motor making some ticking sounds, but jogging wasn’t working.  I went to hook up the scope and bumped the alligator clip that was providing motor power.  It touched something on the board, and the Arduino’s LED’s went out.  Yup, I’d fried the Nano.  Ouch. Oh dear. Had I fried the USB port on my computer?  Apparently not. *phew* No need to panic.   I did not, however, have a spare Nano on hand.  Trying out the jogging was going to have to wait until next week.

Jog On OscilloscopeIn the mean time, I rewired some parts of the protoboard to make it a bit less hairy.  I don’t want accidental short circuits killing things, but I also don’t like clipping the leads on resistors and caps.  When the replacement Nano came, I decided to only connect motor power after I was reasonably sure the other things were working.  I  used the oscilloscope to see if the Nano was producing the expected step pulse trains.

Yup, that seemed to be working.  With some trepidation, I decided to try and hook up motor power again.   Nothing burned out, and it worked!  Next I needed to see if the limit switches worked. I jogged the stage all the way down to the end, and one of my limit indicators on the iPhone started flickering like crazy. But it was the wrong indicator. I swapped near/far sensors and added some software switch debouncing.  The slow linear ramp of the limit sensor was producing a lot of noise when it got close to the logic level boundary.  I’d love to run it into a nice Schmitt Triggered gate.  That would keep the software nice and clean, but if I was going to have PCBs made, it would add area and expense.

I could have made them go-to-analog inputs and just used two thresholds.  That’s probably what I should have done, but  stepping at 1/16 of a step was putting me at 54400 steps per inch, which was really taxing the powers of the accellStepper library and I didn’t want to add much to my inner loop.  That’s probably silly of me and adding two analog reads to my loop wouldn’t matter. Instead, I did digital reads and required a large number of matching consecutive answers before alerting the iPhone. Probably over complicating the code since the real bottleneck in accellStepper is probably its use of millis() not a couple of  analog reads.
Camera On RigNext up was to install CHDK on my camera and see if I could manage to use a USB cable to act as a remote shutter switch.  CHDK runs on various Canon cameras and lets them do things they normally couldn’t.  My camera (a Canon S100) didn’t have a way of remote triggering, so I had to hack it with CHDK  to do that.  You have to make a special bootable SD card.  I used a tool called STICK to analyze a photo taken by my camera, determine the exact firmware in the camera, and download and format a bootable SD card.   This made setting it up simple.  Then I went through a maze of  menus to turn on remote shuttering. I wired one of the Nano’s output pins to my camera’s USB port and wrote a snippet of code to take a picture. It worked! Right now I hold a line high for 1 second, and then it takes a photo when the line goes low. I haven’t tried running a shorter cycle.  Maybe with manual focus/metering it could take photos more quickly.  I haven’t tried.

timeLapseStagetimeLapseSetup

I had motion, I had photo taking. It was time to try and do a time lapse with this rig. I took it over to my son’s Lego studio area and set up a magic crystal garden I’d purchased online.  I used fun-tack and clothespins to aim the rig, plunked an old calendar photo of clouds in the background, and we were almost ready to go.  I set all the camera settings to manual. Then I set the code to move though the system’s full range of motion over 10 hours, taking one frame every 2 minutes for a total film length of 10 seconds.

I waited until it was dark, and I fired off the time lapse.  It felt like Christmas Eve,  and I didn’t know if Santa was going to leave me a time-travel movie or a lump of coal. I told the kids we couldn’t go into the garage for 10 hours. In the morning, I went out to see what had happened.   The first thing I noticed was that one of the big chunks of foam I’d taped up over the garage windows had fallen down during the night.   Oh, oh.  Still, the crystals were fully grown and there were 300 photos on the camera, so it was time to try and play them as a movie.   Unfortunately, iMovie only lets you specify still frames down to 0.1 seconds in length, so you can’t really make a 1/30 of a second one-frame-per-image movie.  Argh!  Photoshop can do it, but that requires loading all the frames into layers. On my machine, loading in 300 big 3000×4000 pixel images was taking for-ev-er.   Finally, I just downloaded some freeware frame encoding tool and used that to build my time lapse.  Then I could use iMovie to add title, fiddle with the sound, etc.  By 11am, I’d finally managed to unwrap My First Time Lapse.  It was over-exposed and didn’t have great focus, but the kids thought it was cool.  Success!

 

crystalsFinalState

 

Angels and Devils: Making A Smoking Man Candle Holder

Second Sketch of Angel and DevilEvery year is build a big Christmas project.   Usually I get started on those projects right after Halloween, but this year I started way late.  At Thanksgiving, I was sitting out on my sister’s porch and  finally managed to sketch something that I liked enough to build.  The problem with such a late start was that I kept thinking, “I need to keep it simple, and depend more on excellent design rather than absurd complexity.”   This would have been great if I hadn’t eventually let the “keep it simple” part fall to the floor.

Devil SketchIn Germany, they have Räuchermänner (smoking men), which are little wooden figurines that have a small compartment to hold an incense cone. The burning incense smoke comes out of figure’s mouth.  I’ve always wanted to make one.   I considered traditional figures like a hunter, and wackier ones like a dragon, but eventually I decided it might be fun to make a devil with smoke coming out of his mouth.  A lot of German Christmas decorations have angels on them, so I thought a candle-holding angel and a smoking devil would make a nice contrasting pair.  I started some sketches and paper cut-outs, and I finally started designing the thing in earnest on Dec.  5th.   That was an epically late start.


I still had some 1/4″ mahogany plywood left over from the Egyptian labyrinth project, so I decided to use that for the devil.  This turned out to be a big mistake.   The devil wing design had very thin spars that would have been trivial to cut out of 1/8″ plywood.  If I had used 1/8″, the laser could’ve been cutting quickly enough that I wouldn’t have problems with the wood heating and catching fire.   Since I had committed to 1/4″,  I had to develop an entirely new technique where I cut the devils in three passes, using a syringe to put water into the cuts at each wing tip and pointy corners that would otherwise smolder during the subsequent laser passes.

Devil Parts On Laser Tail PitchforkThis worked, and it gave the devil an interesting burned look, but having to develop this technique burned a lot of my laser time. Christmas was fast approaching, and every minute on the laser was precious. I found myself sprinting back and forth to the bathroom with syringes of water.  Not good.  I also discovered that if you’re cutting multiple passes in wood, it’s best to orient the cuts so they are perpendicular to the direction of the compressed air blast at the cutting head.  Otherwise the compressed air can blow along the cut and fan any sort of smoldering wood you may have left in your wake.

Laser Cut Oak BaseI really do not like multi-pass cutting.  The wooden bases for the project were thicker than the devil wood, and I was able to cut them very, very cleanly in a single pass.  It’s oak, and the tiny holes you see are vessels that form in the spring.  You can see how they’re not blocked by sawdust and the radial rays are clearly visible radiating out from the center of the tree like spokes on a wheel.  I cut this at 300 pulses per second, and you can see the tiny grooves left by the pulses.  There is no charring or need to sand the edges.  It’s lovely, but I was careful not to have any thin sections or sharp points in the outline of the base.

Devil Smoke Hole MiterThe devil was hard to cut, and he turned out to be somewhat tricky to assemble as well.  I had to hand miter the top edge of the curved side pieces.  I also had to glue a paper smoke dam into his neck since the top of the devil’s body had to be airtight to prevent leakage of incense smoke from his neck.  The first two devils that I assembled still leaked a thin stream of smoke from that seam. In later versions, I suspended the assembled devils upside down and dabbed white glue down into the peak with a long stick to make sure the seam was sealed.

Devil Body Assembly Another way that the devil was much harder to assemble than the angel was the slanted back. The angle forced me to hand sand a bevel on the base. The curved sides made it tricky to attach the front since I needed to push the sides out to get them into the curved groove on the front face, but without disturbing the anchor pieces, and without knocking the bottom plate out of whack. So it was an exercise in white glue octopus wrestling.  If I applied too much clamping force, the slanted back would cause the base to come squirting out and whole process would begin again.


Devil Heads
By the sixth devil, I was quite adept at this, but the first few had some unenviable gaps, which thankfully were not visible from the outside.  I like the way the devil’s beards came out.  They’re the hidden shape of a swooshing bat.  I did some hand wood burning on the horn segments to make them a bit more interesting.  The biggest disappointment with the devils was that when I finally applied the clear coat, the contrast between their faces and the facial hair dropped unexpectedly, and by then it was far too late to switch to black walnut or something else.   

Devil Hands To GlueI like the way their gnarled little fists came out.  Complete with thumbs! They’re made from three stacked segments glued together and then glued to the devil’s front.  Here you can see the pieces ready for some dabs of glue.

The first two devils I cut had some burning on the inside corners of the belly door.   This was because I hadn’t realized those corners also needed some water injection.  Later devils didn’t have that problem, but to cover the first two I hastily designed some little feet  I could glue on over that area.  This design change is why you don’t see any feet in my original sketches.

Devil DoorPartsI also had to punt on having a tiny flame theme around the incense holder because there simply wasn’t enough room, so I switched to a simple ring.  The copper pan that the incense sits in was cut from a 1/2″ copper tube cap.  I used these both for the incense cup and the candle holder.

I chucked a piece of 1/2″ copper pipe in the lathe and used that to hold the end caps so I could cut them off at two different depths with a parting tool.  The only annoyance was that removing the remaining ring of metal from the 1/2″ was hard to do.   The parting operation squeezed the copper rings so they were hanging onto that pipe for dear life, and I had to pry them loose with a giant flat-head screwdriver and a lot of elbow grease.  Good thing I only had to  do that twelve times.

Devil Door In PositionOnce the feet were on and the door was done, the only thing left to glue on the devil was the head of the pitchfork.  I always glued that on last because it’s cut from thin sheet, and there’s no way to orient the grain of the wood to make them strong along their whole length, so they’re quite fragile between the tines where the grain cuts directly across those narrow sections.

Angel Going TogetherThe angels were comparatively simple to assemble. I carefully positioned them on the maple board so the maple’s figure would form the folds of her skirt and sleeves.  I used different wood for her face, neck, and hands.  I used a layering effect with  the hair to try and keep her head from looking too much like 2D extrusion.  I was going to try layering the area with her ear back one layer to make it even more 3D, but that would have required some more hair fragments, and a bit of iterating on the laser to get the ear size just right. Eventually I punted on that plan. So her head is a bit more of an extrusion than I would have liked.  Oh, well.

Angel Wing Mount ClampI did have to have a slightly tricky clamping rig to glue on the top wing mounting bracket.  I used a laser-cut scrap to match the shape of the bracket and make the clamping possible. Then I used some clothes pins to keep the scrap aligned while I tightened up the other clamps.

The only materials disaster I had with the angels was that the 1/8″ plywood I used to make the wing spars was defective, and some of the spars had their topmost layer of wood just fall off. I had to re-cut a bunch of them.  I’d never had that happen before.  I used clothes pins to provide even clamping force when gluing the spar to the feather veneer.

Wing Parts Test Assebly   Wing With Clothes Pins

Glued Angel WingI had originally thought about using white paper angel wing feathers and black paper wing membranes for the devils, but when I was shopping for the figured maple board I used for the angels, I found some lovely dark figured veneer.  I realized it would look SO much better than black paper on the devil.  I already had the veneer I needed for the  angels, so after I’d sprung for the devil veneer, I switched the angel over and never looked back.  I’m glad I did.

One Winged AngelI did end up having to sand a slight bevel onto the very bottom point of the wings to keep them from clonking into the angels bustle, but other than that they were really easy to put together.  The wings are glued to the top bracket, but they are just slid into the bottom bracket.  That keeps them from getting pried off by differential wood expansion of the body and wings.


The only serious annoyance I had with the angels were their faces. A face is so important, and I’d really sweated the design. I ended up trying to keep it super simple. Just a few lines.  However, as I was assembling the angels, I realized that from a lot of angles the laser-etched faces were very hard to see.

Angel With Halo On Graphite Bleed face.Faceless angels are a bit creepy, so I knew I had to do something. For the first two, I used black acrylic and a fine paint brush to darken the lines after the clear coat had been applied.  That was a pretty ticklish operation to do on otherwise finished pieces. It was no fun at all. After that, I simply highlighted the face details with a mechanical pencil. That was nice and easy, but when I used a brushed on clear coat the graphite ran and gave their expressions a somewhat haunted look. I spray coated the last two angels, and their faces came out the best. Nice clear details from any angle.

Angel Face DownOne of the design details I’m proud of is that I wanted a little cleavage V in the front aligned with her hands, but I knew that would look weird on the back. So I positioned the wing mounting bracket so it neatly trims that off, making it look more like a normal dress back.

I wanted to make halos for the angels.  I went wandering through the hardware store to see what kind of rings or loops I could find.  I purchased a few different kinds, but eventually settled on some straight knurled brass lock nuts.  As the giant monolith of Christmas rolled inexorably toward me across my calendar, I decided to punt on the halos.  No one would miss them.

Boring Halo On the LatheHowever, during the Christmas break, I had a change of heart (and a  bit more time), so I decided to make the halos even though that meant giving out a few “halo retrofit” kits.  The alignment holes for the halos were in the original design, so adding them was just an insertion and a dab of E6000.   Simple pimple.  To make the halos, I used a boring bar on the lathe to machine the threads out.  No self-respecting angel goes out in public with a halo that looks like it screws on.  I then had to drill a tiny hole part way through the halo to mount a piece of piano wire.

Drilling A Halo HoleLuckily, I already had the tiny center drill for the job, and I set up a depth stop on the drill press.  Then it was just a matter of clamping and drilling the six golden rings. Four calling birds, Three french hens, Two turtle doves…  Wait where was I?

Halos DrilledHalos With Wires Glued

I used a bit of JB weld to glue lengths of piano wire into the holes.  I glued each wire to the halo at a jaunty angle so the angel would not look like she was balancing a book on her head at Angel Finishing School.

Outdoor AngleThe piano wire feeds down through holes in both the upper and lower brackets on the back of the angel, and a dab of E6000 cements  the wire to the bottom bracket in a slightly springy but tenacious way.  Then it was just a matter of mounting each angel on a base, and adding a candle cup made from another 1/2″ copper pipe cap.

The devil is mounted using T-shaped pins that pass through his floor plate and into matching holes in the base.  The angel is simpler.  She just has two pins on her bustle that align with slots in the board.

I managed to have two sets completely done by Christmas Day, and I finished up the other four sets a bit into the new year.  Overall I’m very happy with the way this year’s Big Christmas Project turned out, especially considering the late start.   I’m marking it down as a success.

Devil With Pitchfork

Devil Incense   Devil With Black Card Smoke

Angel Devil With Narrow Depth Of Field Angel Devil Two Shot With SmokeAngel And Devil Outside angelAndDevilWithSmokeSmall

Making the Gandalf Costume


Pioneer wanted to be Gandalf The White for Halloween.  I had made Gandalf’s sword, but I still needed to make his cloak and hat. In the run-up to Halloween, I’d spent most of my time working on Simon’s King Cobra costume, and then I got sick. In the end, I had to design and sew together Pioneer’s Gandalf hat and cloak in 4 hours on Halloween Eve. I couldn’t even work late into the night because I was still recovering. Thankfully, I’d already purchased the fabric to make the costume. So it was strictly an evening of Design & Build. I set up a folding table in the guest bedroom to act as my sewing room so I wouldn’t have to commute over the hill to TechShop. TechShop is awesome for sewing projects because I can spread out on three tables and there’s good lighting and an ironing board and iron. I still use my own sewing machine because that’s what I’m used to. So working upstairs wouldn’t be that much of a step down, and hopefully I wouldn’t have to iron.

Gandalf Costume PatternI decided to go very simple. I only made two paper patterns. One was for half of the arm and another for the back, which doubled as the front sides. Only two pieces of paper! Simple Pimple. Ok, there were also two piece of paper for the hat. The advantage of working at home was I could actually size the thing to Pioneer’s body instead of snagging a shirt/pants and sizing from that.

Gandalf Costume PinnedI cut, pinned, sewed, and hemmed like crazy. The only things I put on the cloak above the bare minimum were some belt loops, a sword loop, and an extra layer across the back in the shoulder blades area. I’m not even sure what that’s called on a cloak. I should have double-checked the sword loop height because that ended up being a bit low, and the sword was going to be dragging its tip. Thankfully, the belt loop was big enough to double as the sword loop and the dragging sword crisis was averted.

Gandalf HatI had designed the hat with two intersecting cones of paper. Making the inner cone was trivial, but attaching the brim cone piece at just the right position so it wouldn’t kink the inner cone ended up taking three attempts. This was complicated by the fact that I was also pinning in a hat band, so the actual pinning was stupidly time consuming. Finally I got it just right. Before I sewed the hat together, I took one last look and realized that I had pinned the inner cone in inside out! Horror! I was going to have to pin it again, or the seam allowance would be on the outside of the hat. Not …. enough ….. time. I made an executive decision. I sewed it up the way it was, trimmed the seam allowance very close to the seam, re-inverted the hat and did another seam. That way it looked nice both on the inside and the outside, and the only evidence of my mistake was a little bit of cloth sticking out in the hat band area. Later someone told me this was called a “French Seam.” Funny that I made that up as a time-saving measure.  I really should take some kind of sewing class.

Pioneer looked good in his costume.  Perhaps the hat could have been a bit bigger and stiffer, and the sword loop should have been higher, but basically it came out fine.  Mission accomplished.

PioneerAsGandalf  gandalfDrawsHisSword

GandalfShowsOffGlamdring  GandalfNoHat

Pioneer insisted that I take a photo of him falling into the pit with the Balrog.   Here is the photo after massive amounts of photoshop fiddling to make it really look like he is falling.   Maybe I should have tried a bit harder…  I also avoided mentioning that Gandalf the Gray was the one who actually said “You cannot pass!”  It’s best not to contradict the  wielder of the flame of Anor.

GandalfFallingIntoThePit

Building a Motorized Camera Slide from a Dead Inkjet Printer

PhotoJoJo sent me an ad for a small camera slide.  It was kind of a lot of money, and wasn’t even motorized.   I’ve been taking videos of projects and thought that a little motorized camera slide might be a nice way to spice up those kinds of videos.  I  remembered we still had a dead inkjet printer left over from the kids’ “Take  Stuff Apart Day” that we’d done a few months ago.  Inkjets have a linear motion slide inside.  I thought, “Wouldn’t it be cool if you could make a camera slide with basically just the parts from a printer?”

Motor ControllerI didn’t want to have complex control software, and I wanted it to be mostly made from the printer. In the end, I spent about 4 evenings hacking up something.   There are lots of cheap motor controllers out there, so I squashed my initial instinct to hack up a speed controller out of bits from my junk drawer.  I instead decided to act like an adult and order one of these.   With free amazon prime shipping I could have it in two days for under $10.  I’d probably end up spending more on perfboard and components building a  home-brew driver. Plus, if this project was  a bust, there would be plenty of other uses for the driver board since it could drive a much bigger motor than the one in the printer.


Micro SwitchesI scrounged up some micro-switches and a wall wart to power the rig.  I also ended up buying a switch and a project box from RadioShack.  So the total bill for this project was about $20.  I even (mostly) used wire that was taken from the printer.  I really wanted this project to be simple to do in the hopes that other folks could build one.   The interface was fun to design because it’s entirely electro-mechanical except for the speed controller.

Schematic It was fun to design an interface that didn’t have any software but was still nice to use.  I had a direction switch that you could push in the direction you wanted the slide to move, a launch button that would start the stage moving, and two end-of-travel microswitches.  It was fairly complex behavior from a minimal amount of wiring. I was really satisfied with how that turned out.


End Of Travel SwitchI laser-cut some mounts for the end-of-travel switches so they could be mounted right on the rod that the carriage travels along.  The mounts allow the switches to slide along the rod to position where the camera motion should stop.

Probably the single most time-consuming thing was hacking down the carriage.  I used a cutting disc on my mototool to hack the carriage down to a roughly flat area and then used some Bondo/black spray paint to make it look like a nice, flat surface.  I also stuck a short 1/4-20 screw up though the center to mount the camera on.

I was planning on mounting my Cannon S100 to the slide.  It’s light, so the whole rig didn’t have to be super strong.  Luckily, I happened to have a ball-and-socket camera mount sitting around from an old project, so I hooked that up to the screw on the carriage.

Camera Slide Top View  Camera Slide Bottom View

At this point I realized that for a camera slide this small, most of the usable camera motion is VERY slow motion, and the printer’s motor was just not up to the task when running open loop.  If I salvaged the position encoder and hooked up an Arduino as a controller, I probably could have managed to get very nice motion of of the rig, but since the goal was a one-evening super easy/cheap hack, it was a fail.  Putting a gear-head motor in there would also have worked, but also violated the cheap and easy premise of the build.  Here’s a video of the final result.

cameraSlideDone

I wouldn’t be surprised if there’s another camera slider project in my future.  This time with more motors and software.   This was a great learning experience, and as the Lego Guy said, it’s time to “Keep Tinkering!”