Where's Waldo-the-Datasheet?

Howdy gang,

Once in a while, an interesting, random project shows up at 23b's doorstep.  This week's project-du-jour is a rotary encoder / stepper motor drive.  Without getting too bogged down in the details, what we need to do here is read the position from an encoder, and then drive a stepper motor at 110% the speed of the encoder.  This is meant for pulling extruded vinyl out of a larger machine, while keeping an appropriate tension on the extrusion. 

The focus of this post isn't the extrusion puller itself, this is more about the quest I took to find out where the Mil Spec callouts were for this particular connector, so we can hook up test leads while we develop the rest of the project.

The first step was checking the product data sheet.  A "Sick Stegman DGS25 rotary encoder" yielded ample Google results, with the proper data sheet.  Cool, that was easy. 

Another bit of googling for the connector type lead me to the Digikey and Mouser website where it has the proper connector listed (I think), and it's nearly $20.  Screw that, I'll make something here at the shop (why else do we have all these tools?)  After the 3D printer was down for most of the summer due to my dumb ass putting ancient support material through the extruder, I find myself champing at the bit for every opportunity to make a customized, one off piece for any project in the general vicinity.  The printer is an incredibly useful tool, when it works. 

After examining the case a little better, there is confirmation on the physical connector that it is nearly the same part number, calling out CR3102E18-1P-1.  The numbering convention is essentially the same, but why the CR spec instead of MS? 

After a bit more smashing my face on the keyboard, I learn that the CR and MS specifications are essentially the same scheme.  CR spec came from Cannon Electronics in the 50's, and it looks like the Mil Spec connectors were developed a decade prior.  Perhaps there's some overlap?  Perhaps it's similar to the 7400 / 5400 families of ICs.

Checking Digikey for the part number, I find myself puzzled, as the part number only seems to be for the male receptacle of the plug.  What the hell is the mating part called?   After some more face-smashing and context-grokking, I find "Oh, it's a MS/CR3106-18-1, of course that was easy to figure out".  NOT!

Different Mil Spec, different connector callout.  I guess that makes sense. Now where the hell is the blueprint? 

Just looking for the -3102 or -3106 part number didn't yield anything incredibly fruitful at first.  I did find a few diagrams showing pin location, but nothing with dimensional values.  Should be no big deal, perhaps I can figure this out.  Time to break out the calipers and Solidworks. 

After getting to know my Stratasys 3D printer over the last few months, I know that it's for the most part dimensionally accurate (maybe a hair on the small side)  Sure, I could run calibrations until I'm blue in the face, but that won't help too much.  The printer operates in open loop mode, meaning that it doesn't get any positional feedback to make on-the-fly adjustments to the print head location.  Translation - even if I program something at 1.000" exactly, it may come out a tiny bit bigger (1.003") or smaller (.997"), depending on a few factors, mostly the positional tolerance of the machine itself.  I'm satisfied I can program this part to a tolerance that will be acceptable to fit.  Usually, I give loose-fitting portions a +/- .005" tolerance (depending on direction of interference).  Tight fits usually have a single sided tolerance of .002", and we have even successfully produced accurate interference fit parts. 

There's a neat feature in Solidworks where you can superimpose an image on top of your model, so you can draft features based on an imported image.  "Sketch Picture" is the command you'd use, and here's what I did.  I opened up a sketch on the back face of the nearly-finished connector plug, resized the image, and simply drafted new lines on top of the image until they matched.  Mostly.




One thing I've learned while using Solidworks over the last few years, combined on top of my experience fabricating and machining parts, is that if something doesn't look right, it probably isn't right.  With ample training, your brain can become a finely-tuned difference engine, instantly recognizing small changes in familiar objects, without needing to intellectualize what the change is.  The warning alarm becomes a subconscious manifestation screaming into your Neocortex.

These Mil Specifications are quite good about part fitment and mating.  Something immediately struck me as odd while drafting this using my image file.  According to the superimposed image, the holes aren't precisely centered on the face, nor are they parallel, or even exactly aligned with one another.  I didn't think of this as a huge problem, hoping that the generous amount of space around the pins would more than make up for any dimensional inaccuracies of my part.  Take a close look at the centerlines of the part, versus the centerlines of the circles.  It's all wonky and offset, which is what I should have expected using a JPG as a reference. 

 

I printed the part, eagerly burning a little bit of time for the print to complete.  After realizing I am surrounded by assholes, I returned to Mr. Printer, lovingly nestled in between Mr. Coffee and Mr. Compressor.  An excited, anticipatory removal from the machine only led to my disappointment.  In this case, close enough wasn't going to cut it.  The pins were offset too far, something was wrong with my design. 

Shit, it doesn't fit all the way

Dammit.  

you can see a few of the pins barely peeking out

Back to the good ol' drawing board.

So what went wrong?  A quick glance down the holes, and you can see that the pin spacing wasn't quite accurate enough to get us a decent fitment: the plug is jamming on the pin diameter.  Since I gave up on finding the exact dimensions early on, looks like I'll have to dig around on the internet to find the exact specifications for this particular connector.  More Googling. 

As it turns out, there isn't any one specific drawing on the 3106 connector.  Rather, it lives as a subset of the byzantine MIL-STD-1651,where there's a breakdown of all variety of round connectors.  266 pages of connectors, not ordered in any specific way.  Even when searching for the term "18-1", I got close, but not close enough.  Turns out, the X in 18-X gives a variation on the part, usually a rotational value for the pins, and there's umpteen different varieties of rotation, and not even with the same pin population!  

DAMMIT, this last one is close, but rotated 90* off. 

FINALLY, after manually scanning each page of the document (really only about 20 minutes of work), I found the correct specification. 

Strange, even though the pin population is the same as the last spec (18-24), the spacing is just off enough where it wouldn't match, even with a rotation.  Time to update the model with the correct information. 

how about a googly eyed connector?

Close wasn't close enough.  The change in hole location seems to reflect the skew in my first part.  My brain processed the resulting linear offset accurately without needing a measurement.  Now if only my brain could be calibrated for more useful things, like where I leave my keys every day...

A quick revision to the hole locations, and off to the printer.  But wait, things can't be that easy, can they?  Of course not. 

One of the complications I've run across with the 3D printer is incomplete layer slicing. 

Just like reading toolpaths for CNC machines, when slicing a 3D model in Catalyst, it gives a preview of the toolpath before the print, which provides a quick and robust method to diagnose the print quality before finding out the hard way.  Look for erratic motions in the toolpath, or strange insertions of support material.  In this case, we saw both. 

STL file imported into Catalyst

The red lines indicate model material, and the white lines indicate soluble support, typically inserted if there are any overhangs to the model, building up a support network from the bottom up.  Since there weren't any programmed overhangs, why is there support here?

After slicing.  Notice the support material in the middle of the part.  This is bad, something is wrong.

Top view of the same part.  What's with the hole contours? 

Checking out the top view of the toolpath, you can see how some of the holes are artifacted and incongruous with the contours we programmed in Solidworks.  What happened? 

My first clue is the hole size, and the spacing that requires.  These features are getting pretty small, and the spacing between the holes is getting thinner and thinner.  Even though the finest level of print is .010" layers, that doesn't mean that the plastic extrusion is exactly that size.  The extrusion head prints layers that are substantially thicker than they are tall, nearly .020" wide.  This can cause problems for interpreting smaller dimensions, as well as the fill pattern between thin walls.  In this case, Catalyst changed the programmed contours of the circles to now have a bit of cutaway, probably to accommodate for the XY size of the extruded plastic.  While these changes would be minute, since we're dealing with small parts and tight tolerances in the first place, allowing these changes to be made by Catalyst would at best produce a part that doesn't fit correctly.  At worst, it may have messed up the entire print by inserting support material where none is intended - I've even seen whole layers of support inserted in the middle of a print, effectively ruining the model half-way through.

After a few revisions to the part (making the hole size slightly smaller, so the wall thickness can be larger), I was able to find some dimensional values that would happily process in Catalyst.

Much better, Aziz

Notice the holes look right, now?

 So how did the part turn out, after all this trouble?  Perfectly. 

This is a much more satisfying result.  The printed parts fit precisely, as long as they were designed precisely.  Not everything works on the first shot, but success the second time around isn't a bad consolation prize.   

LOSING FOCUS: Practical experiments in visual perception

I made a presentation at B-Sides OC on October 4th.

My topic was visual perception hacking, and how to manipulate your cognitive filters to help you use more visual data. I included several experiments and a handout.

Here are the slides and handout from the presentation.

Losing Focus Presentation Slides
Losing Focus Presentation Handout
Speaking Notes

Waterproof storage for small stuff

Spare AAA batteries kept safe until needed 

Boba straws are available in black, clear, and neon colors, up to a foot long and 1/2 inch in diameter.

They are useful to package any number of small items, including things like the following:

matchestoothpicks
sewing kit
salt or pepper
chili powder
SD cards (red=full cards, blue=blank)
ibuprofen, vitamins, or meds
AAA batteries
watch batteries
lockpicks
escape plans, one-time pads, maps, a hundred dollar bill
a tiny USB drive
a pinch of dirt from a magical castle
a small transmitter or zigbee radioan RFID tag or tiny geocache
Throwies -- UV LEDs, a battery, and a magnet inside a neon straw
spare pencil leads
jeweler's saw blades
X-acto or craft knife blades
baking soda -- used with super glue to fill gaps
hard drive screws, cable tied to the inside of the case 
sharp tools or drill bits
 
HOW TO DO IT:

- Go out for boba and swipe some extra straws , or pay $2 for dozens at your local asian market or online.

- Put aluminum foil over and under the straw to prevent it from sticking.

- Press the straw end with your heating tool, soldering iron, or whatever, moving around until the plastic fuses completely shut.

- You only need to seal once straight across, but more is better.

Improvise if no soldering iron is handy:

  - Fold the end over and insert it into a short piece of straw or a pen cap
  - Close it with the smallest size of binder clip
  - Iron it shut with a light bulb, hot butterknife, or the lid of a Zippo lighter 
  - Melt it with a clothes iron or hair curling iron
  - Heat (or burn) the end with a lighter and squash it flat under a water glass
  - When melting the end, use foil or wax paper to avoid sticking or burning.

You could get all fancy-pants with it too:

  - Make the melted tab longer, and punch a hole for an eyelet, rope, cable tie, keyring, or carabiner to pass through
  - Add a rare earth magnet and stick it to a fridge or toolbox
  - Make a laminated nametag or cable label by ironing in a strip of paper

RFID Blocking Wallet

I whipped this little project up today as a 

proof of concept for an RFID blocking wallet. 

It's simple but effective at preventing RFID reading of your valued card.

Modifying a folding lock pick set

[TLDR] I made a modification to my RCS Tools folding lock pick set to help retain the tension wrench, which could easily pop free without warning. [/TLDR]

The tension wrench can pop out of its storage slot with very little squeezing force. This is further facilitated by the extra-large nail nick, which provides an easy spot for the wrench to be squeezed while on your keys, or inside a pocket or bag. The wrench might also be released by a key or other object levering it out from inside the nail nick.   This modification provides extremely secure retention for the tension wrench, while still allowing easy removal.

 

The edge of the tension wrench is visible along the bottom of the tool.  

A small rivet (visible along the leftmost edge of the tool) was added. A desktop drill press with a #62 (.036) drill bit was used to make the hole.

(This hi-speed rotary tool was too fast by far for drilling such a tiny hole in plastic, but our floor drill press would pretzel such a tiny bit, except that carbide bits would actually shrapnel and fly across the shop, as opposed to actually pretzeling.)

I created the pin from a piece of aluminum wire by cutting it to rough length.  I used short nosed, smooth-jawed pliers to hold the wire so it was perpendicular to the edge of the plier jaw -- this helps me to not sand my pliers. I shortened the wire to just a hair too long, and squared the ends off. 

I rolled the wire between iron plates to straighten it out -- next time I'll do this step before sanding the wire down, since the wire was so short it kept going sideways. 

I used a digital micrometer to get the diameter of the wire, and selected the right bit for the Dremel press. This was maybe .001 under the diameter of the pin for a snug fit.

The pin is visible at the left end of the tension wrench, 

right inside the channel and next to the red handle.

I added the pin where it won't interfere with pick rotation or use, and it seems to have enough plastic around it to avoid breaking out.  The wire bent slightly when i tapped it down flush with a steel hammer because i didn't give it enough support in the middle, but it didn't crack or damage the case and it retains the wrench properly, so I won't rework it just for a blemish defect.

(EDIT: I ended up finding a dowel pin in my junk box and re-drilled, inserting the nice steel pin in place of the nasty old aluminum one. Happily ever after.)

The wrench is definitely retained securely and will only come out when it's needed.

Welding experiment success!

A few weeks ago, I posted to the mailing list for a Welding / Fabrication class, and we had a few people show up to try their hand in making a new addition to the shop, a custom-built shelf for our welding bench.  The old shelf is pretty sad, if you've ever had a chance to meet it. 

It's falling out of the wall

I mean, just look at the thing.  While it served its purpose without complaint for many years, it's Ikea roots definitely show through.  The shelf has perpetually had a 5° slant as long as I've known it, so it was certainly never confidence inspiring enough to do pullups on. 

We're always in a state of flux at the shop, making small improvements here and there as we see necessary.  It all adds up after a while, and people who haven't visited the shop in six months are usually stunned to see how much things have de-Seussified in the interim (in fact, that happened just now when RJ walked in, haha).  Little upgrades like this make all the difference in the world, when you were used to staring at the eyesores like this one.

Looking into the Tested videos shown on the prior posts, there is a neat video on Youtube of Jamie Hyneman's (of Mythbusters fame) workshop, specifically on the custom racks they have holding their boxes of equipment in M5 Industries.  He says, "We buy tubing by the ton".  Well, we just so happened to have a bunch of tubing scraps at the shop just begging to be put to use.  Off to Solidworks!

I quickly drew a few 3d sketches, and then used the Weldments tool to turn my sketch into a solid model.  After a grand total of maybe five minutes from concept to finished model,  then I could use to generate engineering prints, Bill of Materials, mass information like weight and volume, even simulations for deformation and drop testing if we really needed that.  While having all that strength is useful if you want it, what is most important to me is ease-of-use, and how intuitively I can learn new concepts in software.  I went through the weldments tutorial once, beyond that, this is actually my first real-life Solidworks weldments project.  

This was entirely modeled up in a virtual environment before I needed to make a single cut, so when I made a few revisions to the size of the tubes in the sketch, the rest of the model updates instantaneously (along with any other associated information, like the prints and BOM).  Not having massive experience with welding, ANSI-complete prints, nor manufacturing management, what I found this tool was most useful for, was the ability it gave me to convey the important information about this structure to my students taking the welding class.  I simply handed them a set of blueprints with a cut list, and told them "All the relevant information is on this paper." 

They delivered.  I made the first two cuts and welds, the rest was up to the new guys. 

The Noobs followed what few instructions there were, the hardest part being getting a "feel" for welding.  It's something that can't be taught out of a book, rather, it's an art that needs to be practiced.  The biggest problem we encountered was heat management, understanding what's changing in the system when you start welding, and how the molten puddle of steel needs to be manipulated through the welding process. 

Welding steel is not much different than a hot glue gun and popsicle sticks, except it's much much hotter, and it'll melt the popsicle sticks away beneath the glue. With a few basic concepts like that in mind, as long as you're considering what's happening to the heat in the weld, then your results will show a little bit of insight to the process.  Mild steel is a moderate heat conductor, it uses a mid-range heat value (between stainless and aluminum), so it's relatively simple to work with.  Stainless, while it conducts heat much less than mild steel (requiring less heat overall), also has a higher coefficient of thermal expansion, so if you don't carefully tack down your weld in several spots, a whole piece of stainless will bend and bow as you weld it along the entire length, ending up distorted and warped.  Aluminum is another beast altogether, and not recommended for beginners to fabricate with.

 

Tack welds holding everything together

This whole project was built from scrap and leftovers laying around the shop.  If you had to go to the metal supply store and source all of this material on your own, I'd be surprised if you'd be $20 deep into it.  The worst part of this whole project is dealing with that expanded metal grating.  While it's wonderful for filling in open areas like the tops and bottoms of this shelf, it's pretty nasty stuff to handle.  Even the "flattened" grades of expanded metal are covered in lots of tiny sharp edges that will cut the shit out of you the second you turn your attention away from it.  I have to find out these things the hard way.  That's why I order $100 of material at a time, so Benner Metals will deliver the order to me instead. Twenty foot lengths of steel aren't too easy to negotiate, let the flatbed deal with it. 

The mounts had to be reoriented 90° from my initial drawing, mostly due to my lack of considering how much space the grating was going to take up.  Since this part is being mounted to a block wall, I had to get some 3" sleeve anchors and a carbide tipped masonry bit to drill the pilot holes.  The mounts started life as a small leftover piece of rectangular tube from Flea's jeep bumper project, which I quartered into nice flanges and drilled a .400" hole through them.  Once tacked on, I laid a weld bead on the butt joint between the mount and the frame.  I could have filled it in better, but I think a weld of that size would probably exceed the design limits of this part.

Dykem is also known as layout fluid.  I use this all the time to mark parts based on a measurement, to see where I need to make my cuts or holes.  After measuring the parts using calipers, then I gently scribed the intersections of the horizontal and vertical midlines to find a rough center for the mount holes.  Dykem is easily washed away once you're done, using acetone.  In a pinch, Sharpie marker works fairly well, just remember that Sharpies are ruined once you put some oil on the tip, and you can pretty much count on these steel parts being slathered in a light coat of oil to prevent oxidation.  Acetone, you'll come to learn, will be your best friend when working with metal, except when you have even the slightest cut in your skin, which the acetone will seep into and light up any exposed nerve ending with a nice bright searing pain, not much different than squeezing lemon juice all over your broken cuticles. 

The end result - total amateurs (including myself) successfully made a beautiful, custom shelf for the shop.  It's way overbuilt (the way I like it), cheap, and user-servicable.  Want to add some hooks?  Weld them on.  Want more shelves?  Weld them on.  Speaking of hooks, remind me sometime to tell you the story about why this wall is red... 

The top crate weighs +60 lbs.  I'd say this is pretty solid.

My fourth attempt at 3G (vertical up) welds

the finished result - pullup tested. 

Building the LED Pixel Box Part 2: LED Selection

Because the original Tested video had no details of what was built besides what was shown/talked about in the video, I had a few questions about what exactly was used. 

One of the first questions I had when I saw the video was what size box was that and what LED strips did they use.  There are tons of different types of RGB LED strips out there of varying densities and control types, and I have played with a few of them.  So I went about figuring out what strips they used for the box 

The first step is to determine how big to make the box. Taking a look at the finished box in the video I can see the box is square, and it goes from about the armpit to mid/lower belly of the hosts.

Judging by this dimension, and estimating based on the humans I have available. I would say this about 12 inches. This sounds good to me if I am going to apply some DFM principles in this build- lots of raw materials come in multiples of 12 inches (wood, acrylic sheets, lighting diffusion paper etc) so making this box 12" square should make acquiring materials easier, and with less wasted scrap in the end.

Now, to determine what RGB LED strips to use. Adafruit sells many different options available, and sells LED strips at a decent price products are shipped from the US. They also provide very nice product pages with good information and links to good sample code. This isn't about recommending one vendor vs. another, but they are a good starting point with a good reputation, so they are worth consideration. 

The 60 LEDs per pixel and 30 LEDs per pixel "neopixel" strips look nice, but they are not something Ican use. I want to use a RaspberryPi to control these strips, and according to Adafruit's product page:

The controller chip ... protocol used is very very timing-specific and can only be controlled by microcontrollers with highly repeatable 100nS timing precision ... t it will not work with the Raspberry Pi

Well, there goes that option, so now I move on to LED strips which are controlled by external (not on LED) controllers, such as the HL1606/LPD8806/WS2801  as I see on the 32 LEDs per pixel strips. I used a strip like this on the Mobile Club tabletop and strips like these are very common and easy to find on hobbyist sites such as Sparkfun  and Adafruit, as well as ebay and alibaba/aliexpress. There are many different types of strips, but the main variations are number of LEDs per meter, and the level of addressablilty for the LEDs on the strip (each LED can be a different color, a certain amount of LEDs have to the same color, or all LEDs have to be the same color).  For this project, I will need to make sure I can address each single pixel and make it a different color.  You will see LEDs that are "3528" and "5050" The 5050's are brighter. Look for those.

I need to determine the proper LED density.  I know I want the Pixel box to be 12 inches square and be 16 LEDs by 16 LEDs. So 12 inches per 16 LEDs leads us to 12/16 = 0.75, so I know I will want a LED every 0.75 inches.

A strip with 32 LEDs per meter would be an LED every 0.03125 meters, this translates to every 1.23" this is too far apart.


A strip with 60 LEDs per meterwould be an LED every 0.01667 meters, this translates to every 0.65" this is close, but not perfect, and I would need to find a source for individually addressable

But, in looking around online I found LED strips at 52 LEDs per meter- that is an LED ever 0.0192 meters, which is about 0.75" - Perfect! These strips use the LPD8806 controller which will allow us to address each LED individually. I found these strips by search for LPD8806 LED strip and found good sources for these on both alibaba/aliexpress and ebay. In the end, I chose to purchase from an ebay seller based in the US, so I could get my LEDs delivered fast and get a start on the project by the weekend.

In comparing the ebay product shot with the strips shown in the video, they look identical (note the shot in the video is missing the silicone jacket used for waterproofing.

So, it looks like I found the strips they used in the video, and the numbers/sizing adds up, so I feel confident going forward with these parts.

The pixel box will have 256 pixels (16x16) so at 52 LEDs per meter, so we need 5 meters of this strip.

The RaspberryPi and LED strips have been ordered and I am waiting for them to be deliveryed. The next steps are to look into how deep the box should be and how to best diffuse the light.

Building the LED Pixel Box Part 1: Inspiration

Recently, tested.com posted a video of a LED Pixel box to their web page

This seemed pretty neat and up my alley in terms of skills. It uses RGB LED strips diffused trough a translucent layer of film much like we did for the glowing LED tabletop of the Mobile Club.

It also is similar to a project that uses of RGB LEDs as individual pixels - the Rave Rover:

I know there have been many different projects like this, but I think the time has come to make our own, and seeing the Tested video was the inspiration to start to build.

So, my goal over the next couple weeks is to build a Pixel Box like the one seen in the tested video.

Stay tuned for more posts as I document the build process!

First step.. I'm not sure if I like the name "Pixel Box" for this.... Does anyone have a suggestion for a better name?

Shop tip for the day - threading hard to reach bolts

Howdy y'all,

Playing around at the shop today, I had to utilize a trick which has come handy many times, but it took me many years to even come across this trick.  This may be elementary for some of us, but I still think it's pretty nifty.

 Mounting the new control box for the CNC mill today, I had a few hard-to-reach bolts on the case which needed a nut on the other side.  I didn't have room to hold it with my fingertips, and the nut would fall out of the bottom of the wrench if I couldn't get my hand in there.

A simple piece of electrical tape can help retain the nut on the wrench just enough to position it, and then let go once it's started to thread.  Take a small piece of tape and place it STICKY SIDE DOWN on the wrench.  The tape is the perfect size to take up the gaps in the flats on the wrench and gently grab hold onto the nut.

Press the nut into the tape, down into the hex flats, and your nut will be retained nicely without falling out.

And our team of talented artists (i.e. Danozano) produced this exciting combination artist's conception and circus poster:

 

23b Shop Redbull Creation 2013

Redbull Challenge 2013 - sneak preview

Our qualifier entry for the 2013 Redbull Creation contest is due in a few days! We've been soldering, machining, welding, and coding all week.

Check out these pics:

Hint: it flies, and the whole thing weighs about 50lbs.


Arclight

Custom burger tools and putting the pieces together

Here's another interesting project from this week.  We had a small business owner approach us for help building a custom burger tool for his gourmet food truck, Burger Monster.

He drew the design up in Google Sketchup, had the main piece 3D printed, and then needed to make the stainless steel parts.

We sent him over to Schorr Metals for the some scrap, food-grade stainless steel, and McFadden-Dale Industrial Hardware for the rest. After cutting out the 6" diameter burger press, TIG welding a stainless, 3/8" bolt to it, and lathe turning a 12mm-to-3/8" nylon bushing, we have this:

 

 

The Burger Monster Press, version 1.0

For reference, 1/8" stainless is easy to cut out on a horizontal band saw, then smooth out with files and grinder. This is also easy to TIG weld.

The 3D print you see here is easily within our capability range at the shop. A better model would have had less polygon artifacts, but this one works fine.


Arclight

Holy ABS plastic, Batman!

Look what showed up in the mail this morning...

I think this means we need to do more 3d printing.
Come on by May 5th at Noon, and we'll have a class on how to use this fine tool.

-C

Pot Luck 4/20/2013

For those who missed the pot luck last Saturday, here are some of the highlights:

Walter Clark brought in his Wimshurst Machine and did a very interesting demonstration of static electricity and electric fields. Most of the things we think of as electrical use magnetic and electromagnetic effects. Static electricity only shows up in a few modern devices, such as the electrometer dosimeter.

Here's Tayopa cranking the machine.


Also included in the demo was a simple foil electrometer that could either acquire a charge (when touched to the non-grounded terminal of the machine) or detect the charge when brought near.

The sparks from this thing are also impressive. The breakdown voltage of air is 10-30,000V per cm. So the machine is generating over 25KV in potential.




Next, we had the usual potluck stuff, including an awesome dinner and clown bike rodeo.

And we fixed Tim's early 1980s Roland Piano 70 synth keyboard. This one was kind of tricky - we checked the DC power system, used a scope and signal generator to check out the amp stages, and finally figured out that the oscillator boards weren't working.

Going over these again with a multimeter, we discovered that the 3 virtually identical boards did not have identical voltages on the 2 power rails. A close look revealed a corroded trace and a couple of bad solder joints on the +15V rail.  Fixed!

One other thing: One of our mysterious neighborhood characters left a baggie in the parking lot with a bit of crystalline residue. We put it under the microscope at about 25X before disposing. Can you ID this mystery substance? Is it sugar? Is it crack?

A couple of notes on taking pictures through a microscope: If you don't have a scope with a camera port (we don't) then your best bet is to use a longer lens or zoom setting and manually focus at infinity.

When you have that done, disable the flash, set a high ISO and put the camera right up to the objective. This one was done with a 90mm equivalent lens, ISO 1000. Was very easy.






Arclight

HABEX2 - High Altitude Balloon Recovered!

Two weeks ago, 23b and Nullspace Labs collaborated on a high-altitude balloon launch, HABEX2.
Nullspace ran the launch and built the main payload, while 23b supplied a backup RDF tracker and managed the recovery effort.

It was launched from Iron age Road, in the Mojave Desert, CA.   We received digital telemetry during the flight, and our team took periodic direction-finding shots from multiple locations, using a 70cm beacon and Yagi antennas.

After reaching an altitude of approximately 77,000', it burst a bit early and landed right in the middle of the Turtle Mountains Wilderness Area.

Unfortunately, there are no motorized vehicles allowed in this area, and recovery was complicated by the fact that: 1. The area is comprised of extremely rugged volcanic mountains and 2. The last known position from APRS broadcasts and RDF hits occurred about 5 minutes before touchdown, meaning that we would only have an approximate location to work with.

Here are some pictures of the launch:

The recovery trip ended up comprising around 500 miles of driving, an off-road trip down an old mine road, and a 16 mile total hike.

Success! Arko was able to recover all of the pictures and data from the flight:

Check out:
Flight Pictures (full set)

Arclight

Red Bull Creation qualifier

We got the box of parts from Red Bull, here are some pics.  We have to make something awesome and interactive with light.  They sent us a custom board with arduino hardware on it, some screw header terminals, 2 RGB LED ropes, and a lightbox.   Any ideas about what you would like to see made with these ingredients?

23b Shop Psychic Defense Briefing
Mid Q2, 2013

 

 

PHOTO: One advanced hybrid component of the 23b Shop Automated Defensive System Project, wielding one of the numerous razor-sharp implements available at all times for ready brandishing.  (Note his unusual inward-facing stance, which indicates that he is currently protecting the outside world from the release of shop inhabitants.)
 

(Ed. note: Apologies if the tech level is a little higher than we normally present in our "recent shop events" postings, but this was an in-depth investigation and we have a lot of useful research findings. -Dano)
 
1.  Primary research

The stylish headgear in this photo is much more than it appears at first glance.  Made by hand from proprietary .003" NASA FOIL in 304 stainless steel, this imposing piece of modern psychic armor is folded from a single, geometrically perfect, seamless square using a fusion of ancient Origami techniques and sculptural pinch folding.  No cutting or other modifications to the original square except for folding were allowed, to prevent potential gaps in cerebral coverage.

This headgear shields the user not only from dangerous inbound mind scans and gamma field mind control rays so prevalent in modern urban areas, but also presents passive interference to unwanted thoughts and internal influences by virtue of finite subharmonic design principles used in the dome shaping.

The unique microcorrugations were pressed into the material at manufacturing time. They are distributed in a bisymmetrical, isometric Leyden lattice of approximately 4.1mm granularity per current research in passive homomorphous brain waveguides, and have been statistically useful in our recent research on the influence of user thought patterns.  In this case, we are seeing the subject's normally fierce demeanor attenuated (albeit only slightly, at an estimated level of Cb=0.031, in the moment of this photo) via implantation of hybridized kitten-based thoughtform images.

The cerebellar shielding (not visible in this image) prevents low-level attacks against the reptilian hindbrain while still allowing basic bodily functions even during constant low-level external mind influence probes, Baissan-field scanning, and VX cloud manipulation.


2. Unexpected results

As measured by the diminishing population of acceptable subjects to be found in the shop's dumpsters and surrounding abandoned areas, our old invasive "electrode twiddling" methods didn't allow us to keep subjects functional for long.  It's not like you've burned out a 15 amp car fuse; we're hard pressed just to pay the B-waste fee to recycle the burned out minds of unsuccessful subjects. Even despite these troubled times, our local scrap scavengers are not likely to pick up our old test subjects, so they pile up outside, causing unwanted questions and attention.

Control of the autonomic functions of the subject can be instigated by uptake inhibition of sardon flow, as has been discussed exhaustively in the hackerspace community. (Search it yourself, i'm not going to waste space with links for something so easy to find).  However, this is the first time we have had such dramatic success with noninvasive procedures. 

The helical cornuvortices (the "horns" present near the lateral forebrain) are shown to be effective in damping the sardon flow from the pituitary region via the special focus chevron in the reverse Brazilian style frontpiece. This is key. The sardon damping pattern is further shaped via the focused deep-channel tuning antennas, visible as tuned wire arcs around the sides and lower portion of the headgear. What a vast, vast improvement we've seen over the old style "tinfoil hats", with their expensive and fiddly platimum foil probes inserted directly into the area surrounding the pituitary gland!

We're glad to avoid the liability and mess in this kind of research, not to mention that our bill for hydrogen peroxide to clean up the implant area of the shop was getting to be more than the cost of electricity for running the Imbridge field generator to quiet down the subjects in the cage area.

Waveguide research of the last 40 years obviously figured prominently into this design, and we can proudly claim that we are on the forefront, nay the bleeding edge, of cornuvortex research here at the 23b Shop.  We are also proud that we have lost 7% fewer research participants to gibbering madness in 2012-13 over our previous research years!

Build time was approximately two of your Earth hours. By the April potluck, we are hoping to have Arduino-based will-damping implemented in the cerebral stack.

?Future plans?
 ----------------
- Possibly an adiagetic sound implanter hooked up to Skype
      easy verbal remote control of the subject ("God-mode")

- Stream videos direct to the user's visual processing complex (VPC)
      more subtle and purpose-driven control and takeaction processing

- Stream videos from the subject
      useful for monitoring the shop status
      doing livecasts of talks
      stuntcam, etc

- Security drone clown bike with a live controller/actuator component

- Build API for control from existing open-source shop security system

- Charlieplexing-- can we control multiple areas of the brain with fewer pins?

- The dongle controller has been suspended for now.

Thanks to the Rice Underground Walk/Swim Team and Go-fast Institute for their invaluable assistance in conducting this exciting and informative research. We couldn't do it without the support and inspiration of our many colleagues, materials procurers, and affiliated research groups.

PARTICLE CLOUD CHAMBER

This cloud chamber was made with a gallon glass jar, an aluminum plate, silicone caulk to attach them together, a couple of sponges, and a plexiglass lid. There is a foil electrode in the jar which is not visible in the video, charged to 300 volts (AC, i think) with an external power supply. This prevents the vapor trails from lingering, and allows the new trails to be more visible.

We poured 99% isopropyl alcohol into the sponges, which are attached at the top of the jar.  The jar is attached to the plate and the plate rests on 2 blocks of dry ice ($6) from the ice cream distributor down the block.

 The radioactive mineral sample in the jar emits particles which leave ionization trails behind. The trails act as seeds for the supersaturated alcohol vapor -- you can see the little lines of vapor appearing in the space around the rock.  It takes 15 to 30 minutes to get cold enough for trails to show, and the dry ice we used would allow it to operate for about 6 to 10 hours. 

This is a cheap and easy experiment that shows you something really interesting that happens around us all the time.  We will definitely be making a larger chamber with an insulated dry ice compartment and a larger viewing area.

3D printer introductions, shenanigans, and actual useful things!

Offloading at 3 AM, thanks Erik and Arclight!

Howdy gang!

Well, if you haven't been formally introduced to our newest addition to the 23b family, take a good look at Mr. Printer, a close relative of our Mr. Coffee and Mr. Radar!

Not to be easily confused with a RepRap or a Makerbot, This is a Stratasys Dimension 768 SST, which stands for "Soluble Support Technology".  This printer is special for the dual extruder heads, one of which lays  "soluble support" alongside the ABS model itself as it's being built, to provide an extra structural bracing, allowing us to print unusual contours that lesser printers only dream of.  Here's what I mean.


Notice the darker layer of material that is around the base and certain structures of this print.  That is the support layer, meant to be dissolved away once the print is done.  It appears black in this picture, but it's actually dark brown, slightly translucent, and remarkably brittle (warning! removing by hand will cause slight amounts of bleeding, it forms shards!).  It's unclear what the proprietary material truly is, but I was warned by a trusted source to keep the support material dry, as it will absorb moisture from the atmosphere and clog up the extruder head. Another unusual characteristic of this material is that it goes into the machine as a white filament, and comes out a totally different color.  I'd suspect a sugar addition to the plastic, as it has a burn caramel color (but no odor).  This is also the older style support, the newer machines seem to have a material that does not change color as it is extruded.

It's hard to speculate further on what the material is without a chemical analysis.  Strangely enough, at a recent trade show, I met with a local company who compounds polymers, and also does reverse engineering, should the need ever arise.  Heh heh.  The support is most certainly not PLA, the water-soluble print material that bukobots and certain other printers use, as the extrusion temperature for our material is approximately 240 C. 

Another clue to this support material's properties is the way it is removed.  Stratasys sells another piece of equipment which appears to be a large circulating bath with some special witch's brew.  Upon closer inspection, I am instantly reminded of the large ultrasonic cleaning tanks I used at my last job.  The acrid smell of strong, scalding detergent is unmistakable, I recall my hands being extra clean due to the powerful additives in the cleaning formula 

Without a spare $1000 to spend for the special cleaning device, we quickly hacked a solution to dissolve the material away.  This past summer, we scored a small, heated ultrasonic cleaning tank from Ford Electronics.  Dusting it off and quickly filling the stainless tank with sink water and Boraxo soap, (hey, it was plentiful and nearby) the dino head was left overnight to cook and buzz away.  Once morning came, and I returned to check it out, nothing happened; all the support was still attached.  As I suspected, this witch's brew needed some more "pep".  We found an old bottle of Red Devil Lye to raise the pH.  With a small sprinkle into the tank, the head was left for another night.

Voila!, that was the trick!  Out came the model from the hot, steamy, familiar smelling tank looking pristine and finished. 

Strangely enough, this is already made of dinosaurs

 So what do we do now with this printer?  Well, for the moment, we're working on getting the cost down.  It's neat to have around for making models and Gyro-cubes, fully-articulated chains printed in place as an entire assembly, as well as other neat examples.  Currently we're stuck to using the $250 material cartridges from Stratasys, so that seriously hinders our Yoda and dong-making abilities.  Don't forget, this machine has a HEATED work envelope of 8x8x12, but the special Dan-O-Matic model that large would be a tad expensive.  This all works out to be about $5.00 a cubic inch.  For reference, the model above was nearly 10 cubic inches of model (and 3 of support), so this dino model cashes in at a cool $65.  

$65 for a tiny bit of plastic?  You've got to be kidding me.  This should be at most a tenth that price.  Don't get me wrong, I do not underestimate the value of having a 3d model that was downloaded off the internet, created with virtually no effort or skill.  Yet here I am complaining about the small price of cutting edge technology.  First world problems, right?  Wrong. 

This technology is DISTRUPTIVE.  What I mean by that, is there are incredible changes approaching in our manufacturing paradigms, the old way we do things.  By implementing this technology in creative, novel ways, we can now design parts that were impossible, unthinkable to manufacture only a generation ago, then share our designs instantaneously across the globe, FOR FREE.  In my own short lifetime, I've seen CAD change dramatically (I started with CAD on  Brøderbund Print Shop several decades ago), and only in the last few years have the tools and software advanced to the point of being cheap enough for the general public to afford, and powerful enough for them to fit on our laptops.  Sure, the Stratasys printer is a bit pricey, and a RepRap is hokey and hard to setup, but consider this: remember computers in the 70's?  Either you had these homebuilt, hobby units built by geeks with their friends, operated by switches and lights, or you have these large, prohibitively expensive industrial units that not every homeowner can deal with.  Surely nobody in the 70s could forsee the proliferation of computers, or how dramatically they would change our lives.

The price gap between the professional models and the industrial ones is quickly closing in, tracking along with Moore's law, albeit not directly.  Soon the line will be blurred altogether, and then these things will be in the hands of the masses.

We can't afford to ignore the significance of that fact.  This technology WILL change many things.  Even President Obama is keen on the idea of 3d printer:

   "A once-shuttered warehouse is now a state-of-the art lab where new workers are mastering the 3D printing that has the potential to revolutionize the way we make almost everything"

Sound like anywhere you know? 

It's hard to say exactly where this technology is going to head into the near future.  It's impossible to tell unless you're at the front of the wave, and even then, it's always churning and tumbling over itself, exposing a new leading edge.  I can assure you one thing, we'll never have a big problem with 3d printed guns. 

If you haven't heard of DEFCAD, and the related Defense Distributed, now you have.  Their project was started as an extension of some "misfit" files that were taken down from Thingiverse.  Someone was apparently unnerved and uncomfortable with the thought of 3d printed AR 15 lowers receivers (the part designated by the ATF as the firearm), so Bre Pettis played it safe by removing the misfit files altogether from the website.  Understandably, this new technology is scary if we can suddenly start printing unregistered weapon parts, but not every makerbot can do this (yet).  Not to be deterred, DEFCAD carried on.

With some more wind in their sails, they collected some money to get a 3d printer of their own, Stratasys uPrint.  A fine printer in itself, also using the same soluble support technology (which is ESSENTIAL to producing the AR15 model so accurately) they could now make their own parts for experimentation, as well as develop their strategy, which seems to be some libertarian, texas-gun-slinger 2nd amendment fapping.  Which is totally fine, especially now that they have their ATF license.

However, Stratasys was slightly uncomfortable with Defense Distributed's approach, and quickly revoked their lease this past September, due to the questionable legal status of DD's operations.  Keep in mind, this was all before DD got their ATF license, which happened only in the last few weeks.  In retrospect, it was probably good business practice to keep the Defense Distributed project stalled for a few months, as there was enough commotion of unfortunate gun incidents in recent news.  Honestly, those happen all the time, as pointed out on the DEFCAD FAQ.  I suppose until there is an incident involving a 3d printed gun, they now have a taste of legitimacy since the recent ATF ruling. 

Determined, Defense Distributed was steadfast in obtaining a high-quality 3d printer for their own use, and this time looked to Objet for one of their $40,000 UV-cured resin printers (3X the price of a uPrint, the original machine).  These printers have a much higher resolution than the Stratasys machines, due to the technology being dramatically different.  One ironic point of note, Stratasys and Objet merged a few months ago, and now command about 60% of the rapid prototyping market.  Whoops! 

Another point to remember is that some of Stratasys' biggest customers are arms manufacturers and defense.  They're putting a huge 3d printer on every aircraft carrier in the US Naval fleet!  There's even an entire 3d printed M4 rifle at the Stratasys office in Rancho Cucamonga.  Not just the lower, the entire assembly as well as the case are all 3d printed.  Obviously, Stratasys is pro-gun, they're just in a different line of business.

3D printing is making it's debut in the public eye as we speak.  The last PR this technology needs is a Yosemite Sam to introduce something new and unusual, with bullets flying out of it, to the general public.  Surely the Bald Eagle story is a better place to start winning the hearts and minds of the masses. (ironically, the eagle is in need of a beak after a poaching accident).Yin and Yang.

Remind me again why this won't be a problem? 

3d printed objects don't scale economically. If the first print costs $120, the 1000th one will also cost $120.  Compare this with injection molding.  There's a prohibitive upfront cost for moldmaking that requires special equipment and highly trained operators.  Well, once it's up and running, one injection molded part can be produced with 15c of plastic every 30 seconds.  With 3d printing, each receiver takes about 15 hours to print, and another 8 to dissolve the material away, and will always cost  $120. 

Compare this further with CNC machining.  I was at a shop last week that produces AR15 lowers on their 5 axis CNC mill.  $15 of aluminum and 1.5 hours of machining time (nevermind the lengthy programming time and experience required to do so) produces a REAL AR15 lower, made the way it was intended.  Again, this is a completely different discipline, but if looked at against this light, if real, mass-produced, ALUMINUM weapons aren't a problem in today's world, we're certainly not going to see a problem with inferior, lower strength PLASTIC ones. 

We've all seen enough Elmer Fudd cartoons to know what happens when a gun malfunctions, right?  I don't think I need to experiment for myself, thank you.  I'll leave that experimentation to you guys.

SO WHAT KIND OF COOL STUFF ARE YOU DOING INSTEAD, MACHINIST?

I see the start of 3d printing taking baby steps toward the unknown.  The printer by itself is a neat toy, a novelty without a whole lot of direct use, but when integrated with other tools, the resulting combination creates a holistic environment of problem solving. 

THE HELL YOU SAY?

I used the 3d printer to make unique, one-off fixturing for the Bridgeport mill.  Flea came in this weekend with a challenge for the machine shop.  He needed to modify a huge ball joint, there wasn't much to grab on to with the vise.  In this case, a set of custom soft-jaws with a 1" diameter shoulder on the inside to grab the only exposed area of the ball joint.  They worked together swimmingly!

$12 of material, 2 hours of print time, and any Reprap can print this design.

I could have made some higher quality soft jaws using more solid delrin or nylon, but consider the time to find the stock, cut it to size, drill and counterbore the holes in the right location, set up the boring head, only to use the fixture ONCE.  I avoided all of that with about 10 minutes of using calipers on the old jaws, made a quick Solidworks model, and let the printer do its work.  While it was busy printing away, I was free to continue doing other work, instead of screwing around making jaws from scratch, THAT is the most striking, tangible benefit of this technology.  Next time I need some soft jaws, I won't even need to spend the time making the original model, it's ready to go and proven!  We even know that they're perfectly flat and square, dimensionally perfect!  Wow!

They weren't the most solid feeling jaws in the world, and upon further inspection you can see the stress in the material at the thin point of the radius on the jaws.  But for only needing to work once, I imagine that these have far exceeded their original design intent.  Plus, if I flip them, they're still fresh and machinable for another project. 

The moral of the story?   Find a 3d printer to play with, go learn a little Solidworks (or your preferred flavor of CAD), and use it to solve problems, because that makes your brain grow. Or use it to cause mischief, because I'm cool with that too. 

Stay tuned for more. 

Beginner electronics book review

I read There Are No Electrons: Electronics for Earthlings by Kenn Amdahl recently, and believe it would be a very useful book for anyone who wants to learn about basic electronics.  This funny and readable book shows you the basics of AC and DC electronics in a very easy manner, using fantastic illustrative stories about dancing chickens, green buffaloes, a naked Norwegian girl in a boat, and everything else except electronics.  It's much easier to absorb silliness than a dry textbook of formulas and numbers, and it all comes together.


The book covers the fundamentals of electricity, AC and DC current, resistors, capacitors, inductors, transistors, diodes, and how they work on their own and in circuit.  It explains electrons and the different ways their flow is described by conventional and electron flow notation.  It gives you good explanations for why everything behaves as it does.

I'll put my copy in the shop library. It's only about $10, so you should give it a look here, and then maybe go buy a copy.