Appearance In, and Report From, Beijing

Next Friday at 7PM I'll be speaking at what is described as a TED-like monthly lecture series at the Beijing Haidian Culture Treater (海淀文化小剧场). The event is open to the public, but some kind of ticket is required, which you get in some kind of complicated way that involves a lot of Chinese I don't understand. Here is a link to the event description:

In the mean time, here is a small update from Beijing. First, hotels—at lease my hotel—have robots to deliver small packages to guest rooms. I'd ordered a replacement for the Apple Pencil I forgot at home, and when I went to pick it up from the desk, the bell captain kindly agreed to send it by robot so I could follow it to my room....

When it gets on the elevator it says "I'm a little girl and I'm very nervous about getting on this elevator! Please give me the space in the middle!". There are many questions. For example, how does it push buttons on the elevator? When it got on, it asked, in its nervous-little-girl voice, for someone to please push floor 15, but no one did (including me because I wanted to see what it would do). The answer is that it is actually in telepathic communication with the elevator, because floor 15 pushed itself moments later. Perhaps it's just asking because people like to be helpful, and it's trying to endear itself to passengers (while demanding, in a cute way, that everyone get out of the way).

Second question: How is it going to knock on the door to my room? At the very end of the video you can just about hear the answer: It is also in telepathic communication with the phone system. A few seconds after arrival, the phone in my room rang. Unfortunately my room key was messed up so I couldn't get in to answer the phone, but I'm going to assume that it would have been a kindly robot mom saying "Hello nice hotel room occupant, my very nervous daughter-robot is at your door to deliver a package, could you please open the door and pat her on the head? Er, I mean, push the button on top to open the delivery compartment?"

China is very kid-friendly in many ways. For example, I had lunch outside Beijing with laser cutter engineers in a huge restaurant attached to some kind of bizarre children's paradise. You know those pretend backhoes they have in playgrounds for kids to dig with? The ones made of just a few metal bars that are entirely kid-powered? Well, here they are real power shovels with working hydraulic systems. God how I want one of these. They also have a sketchy-looking zipline and a large area that looks a lot like a paintball range, except it's a playground.

Back in town the next day, I was finally directed to the proper set of buildings for Beijing's electronic components market. (I tried to find these buildings last visit but only found nearby ones that were not quite right.) It's two buildings, one 4-story, one 6-story, filled entirely with farmer's market style vegetable stalls, except all the vegetables are capacitors, resistors, connectors (SO MANY CONNECTORS), chips, LEDs, potentiometers, heat sinks, power supplies, and so on forever. 

I had been warned by the laser cutter engineers that I would probably not find stepper motors, and we did in fact walk around for a good hour without seeing any. (I told my translator that this is what it's like when a girl takes a guy clothes shopping. It just seems like hours and hours of endlessly pointless walking around not buying anything. Actually there is a deeper logic to the activity.)

As time was running out, we finally hit the jackpot: A stepper motor vendor who had a sign saying he was closing his shop soon, everything on sale!

I didn't take a picture of them, but I got a super deal on six of exactly the stepper motors I wanted, plus over-sized drivers. I had calculated that I wanted about one Newton-meter of torque, but since my excellent translator is non-technical, this was a bit difficult to communicate. Finally I heard the guy saying "new me" and I leapt on this to ask, through the translator, how many new me's the motor had. One! Perfect. $145 for six motors, controllers, and pulleys, maybe 1/3 what I'd expect to pay from a proper supplier in the US.

Why do I need six stepper motors? Because I have a six-heddle loom that I want to automate. I'll mount them above with strings going down to lift each frame. Connor will be pressed into service to make an Arduino controller that will step through the desired pattern sequence.

Here's a couple pictures of how I was warping the loom just before leaving for China, complete with high-stakes cat:

It has what is called a sectional beam, and the thing I made to hold the yarns is called a warping rack. Combs (literal hair combs) guide the yarns to the beam. 24 yarns fill a 2-inch wide section of the beam (12 yarns-per-inch).

Here are videos of both ends of the yarn path:

24 yarns makes 2 inches, do that 12 times and you have a 288 yarns over a 24-inch width. Unfortunately I miscalculated and only had half as much yarn as I needed, so I only got half way and will have to finish with more yarn when I get home.

3-Week Laser Cutter Update

I’ve had my new laser cutter for three weeks now, and I continue to be very impressed with its capabilities. I’m currently in China (see picture of crazy intersection outside my window) visiting the manufacturer, mainly to learn more about it and their other models. So I thought I would make an omnibus blog post showing the things I’ve been able to make so far.

At this point I have four mostly complete, smoothly operating mechanisms, shown here in my hotel room in Beijing. (Some of these have been in previous blog posts, others are new.)

First, this lock mechanism is slightly improved from previous editions, with pin numbers (so you know what order to put the pins in when assembling it) and an acrylic chain link holding the insert to the other end of the lock. The springs are still fake. Not shown is a matching lock picking tool for leaning how to pick locks.

Next up is the improved spring scale. This version is reliably smooth in operation, and has a dial that goes up to 11. The acrylic springs break when they are stretched about twice as far as the design allows them to, so I think it should be pretty robust.

This is the real spring scale from which the design of my acrylic version is taken (loosely). I've replaced all the outer covers, the weighing platform, and the dial with laser cut/engraved duplicates, so you can see the mechanism inside. But you still can't see it as clearly as in the diagram. My hope is that when people see the real thing side-by-side with the acrylic model, everything will be obvious.

I don't have an acrylic model of it yet (and may not make one), but here is the much bigger, and much nicer Toledo scale, which uses a counterbalance system in place of springs. It too has laser-cut replacement covers and dial.

Here is a small child for scale (ha ha).

This is the new, much elaborated 7-cylinder form of the radial engine described in a previous blog post. Most real designs had an odd number of cylinders, so my previous 6-cylinder version was not ideal. This one also has engraving lines representing the cooling fins, and if you look closely, you can even see dummy valve stems and spark plugs. I thought about adding actual valves, cams, and lifters, but decided that would be insane

Finally, this rope machine is very pleasing to spin. I'm really quite surprised that it runs as smoothly as it does. I didn’t think laser cut plastic could be such a practical engineering material.

Moving on from machines to art, this is the laser-cut version of Nina’s $1000 bill (mentioned in my previous blog post and repeated here so I have one post with everything I've done so far…).

Here’s a video that shows just how fast the engraving works.

The main problem is keeping the power level low enough, and the head speed fast enough, to avoid going too deep. I have since learned, from the manufacturer’s engineers, that it would probably work better to engrave this in raster mode (where the beam does horizontal scan lines). This seems counterintuitive to me, so I’ll be eager to see how it comes out when I try it that way.

My hotel is very nice. This is what I had for breakfast.

Laser Money

Very quick post here because I'm about to leave for China in an hour, but I had to show y'all this because it's so neat. My new laser cutter, as it happens, accepts exactly the same DST files as the quilting machine. So what happens if you give it Nina's $1000 bill pattern?

Well, it works. This thing is fast!

Here's the final result:

More later.

6-Cylinder Radial Engine

Boy is this fun! Today's model is a 6-cylinder radial engine:

It's made with two layers of 1.44mm (rather thin) and one layer of 5.28mm (about 1/4" thick) acrylic. The pistons, link arms, and star-plate in the center are all cut in-place in operational arrangement (as in the CAD file above). In other words, you can simply slide it out of the laser cutter (being careful not to let any of the parts drop) and it works. Here is the main layer in raw form, with the protective film still on:

Getting the top and bottom plates screwed on is a bit tricky, but here it is all assembled:

The disk in the center is basically the crank shaft bearing. It's the rotation of the big disk within the cutout circle that keeps the crank shaft rotating about its center. The offset hole then caries the star plate around its orbit, operating the six pistons in order. (A certain wag who shall remain nameless complained that there were no operating valves, so I declared it to be a 2-stroke engine whose valves are just holes (not shown) in the cylinder walls.)

What blows me away is how smoothly this thing operates. I did not trim, sand, polish, or in any way manipulate any of the operating parts: everything is exactly how the laser cutter left it. All I did was add the nuts and bolts to hold it all together. Watch this!

Who needs a fidget spinner when you have a 6-cylinder spinner?

Although I had always been planning to make some engine models, I admit that the details of this one were inspired by this really cool cardboard version. Which reminds me that I need to add some engraved details around the cylinders.

Meanwhile, my cotton field is doing nicely. I weeded it this afternoon and it's looking good. A transparent cotton gin is next in the list of projects for the laser cutter.

Visible Lock

My purpose in getting a laser cutter was to make visible mechanisms, in order to make their operation clear. Here's the second example I've been working on: A visible pin-tumbler lock. With the key out, pins block the "core" from moving. But when the key is put in, the pins are all lifted to just the right height so that their tops line up along a "shear line". In a typical padlock, the core is then free to rotate, but in this version (as in some bike locks, for example), the core can instead slide out far enough to free a latch previously held in piece. Watch the video and it will all make sense (which is of course the whole point of making these things).

What the video doesn't show is that you can also pick this lock in the traditional way, by tensioning it (pulling gently on the core) and then using a thin tool to lift the pins one at a time until you find the one that is binding, then repeating until they all clear.

By the way, notice that the "springs" are completely bogus. In a real lock, springs push the pins down, but in this one the springs just act like small weights. The lock has to be held vertically so gravity can act in place of springs. Why did I do it that way? Because I haven't yet been able to figure out how to make acrylic springs that are weak enough to work for this situation. Everything I've tried has pushed way too hard, making it impossible to insert the key without a lot of wrangling. Acrylic is a terrible material to make springs out of, though I did get some extension springs to work pretty well in my previous mechanism.

Playing With The Laser Cutter

In my last blog post I reported on the arrival of my new laser cutter.... Today some videos of the first day and a half of playing with it. First let me say, this machine is AWESOME. I was expecting at least a week of frustration before it did anything sensible, but it basically just started up and ran right out of the box. I have not even had to touch the laser alignment despite its having been shipped across the country, tipped on its side, etc, since it was first put together.

It was a good call putting this thing in our side-building (a former drive-through bank, basically a bunker with bullet proof glass and a completely separate ventilation system from the main office building). It came with a powerful blower to extract fumes, and this turns out to be really quite important. Burning plastic smells terrible! I'm paranoid about setting things on fire, so I replaced the supplied plastic ducts with metal ones. The box in the middle is a water cooling unit that circulates cold water through the laser tube. (The shelf above it is the former money drawer, for passing things to customers outside in their cars. Sadly it doesn't work anymore.)

There is a lot of stupidity with file formats trying to get patterns into the machine, but that's not the fault of the machine, it would be the same with any model. Remarkably, in some cases I have had to resort to using the DST file format to transfer a design from Mathematica into the software that operates the machine. Why? Because bugs in Mathematica's DXF export make that not work, and I happen to have an elaborate body of code for exporting DST files, developed for use with our quilting robot. Why is this silly? Because DST is a decades-old format originally implemented on punched tape. It's limited to 0.1mm resolution, which is not good enough, so I have to expand the pattern by a factor of 10, then shrink it back down again. Oh well, I'll get some workarounds in place eventually.

Anyway, here is a video of the first real thing I tried to cut, a model of a spring-dial scale:

The version being cut here didn't work, but after several iterations I got a working device.

Making springs out of acrylic is sketchy, because the stuff is very brittle. But with enough zig-zags, I got springs that are able to stretch as far as they need to without danger of breaking. The scale is not "calibrated" in any sense of the word, and is super inaccurate, but that's not the point. The purpose it to let you understand how the mechanism works with a simplified, cross-sectional sort of mechanism. (When placed side-by-side with photos/videos of a real spring-dial scale, everything will make sense, I promise.)

After making the model scale, I started cutting and engraving transparent replacement dials to go on a pair of real scales (one spring scale, and one huge no-springs Toledo scale). My idea is to replace as many as possible of the cover plates and the dial face with clear acrylic, so that we can photograph the scales in operation, but you can see how they work inside. Creating the pattern for this involved spending a couple of hours carefully measuring the original dial, and writing Mathematica code to recreate the tick marks and letters as closely as possible. (Toledo uses a very strange font, and they are currently looking to see if they can get me a version of their old corporate font to make the numbers closer to the original.)

This scale dial is huge! 60cm, or nearly 24 inches, in diameter. Interesting, I think, that all the dimensions of the dial are clearly in metric units, even though it was made in Toledo probably in the 1950s. How did that happen? I have a book on the history of the Toledo scale company that will hopefully explain things to me.

Here's a picture of the smaller spring scale with its transparent replacement dial temporarily in place. Sorry for the mess, it's my garage. We will clean up and repaint (the scale) before taking the real pictures. Notice how the mechanism inside mirrors the acrylic model from above, except it's harder to see how it works. In both cases there are a pair of springs, and a rack-and-pinion gear system to turn linear movement into rotation of the dial pointer.

Next I'm working on a lock mechanism, which isn't working very well yet.

Meanwhile, Connor is having fun not cutting all the way through a piece of 1/2" acrylic. This is a time lapse of his depth test, varying the laser power level. I'm surprised how consistent the depth is. I didn't think you could do this with a laser cutter:

It's HERE!

It's Here!

It has parts!

It's huge!

It fit through the door!

It has a nice big working area!

It has a laser!

And a cutting head!

Yes, you guessed it, I just got a laser cutter! I'm so excited! I have no clue how to make it work!

This is a GU Eagle Advanced Automation model BF-1309 laser cutter, basically the small end of large-style laser cutters (it is, in fact, the smallest model offered by GU Eagle). It has a 130W CO2 laser tube, a water chilling unit to keep the tube cool, and a big blower fan to suck away the smoke and fumes from cutting whatever you're cutting. (I got a good deal on it from meeting the CEO on a recent trip to China.)

Why did I get a laser cutter? I'm starting on a new book project and I "need" it to make what I've decided to call "mechanical GIFs". It's too hard to explain what I mean by that, but hopefully pretty soon I'll have a couple that I can post images of (assuming the whole concept ends up working out as I hope it will).

Public Appearance at BookCon, NYC, June 4th, 2017

From time to time I get asked if I do public talks and the like. The answer is, yes, sometimes, but not a lot, and usually I forget to announce them in advance. This time I'm trying a new approach: Actually letting people know about it!

I will be appearing on a panel with two other authors at BookCon 2017 in New York this June 4th at 2:30PM at the Javits Center. Here's a page with the details:

Hope to see you there! (And if you ask nicely after the show, I'll probably let you look through a hand-printed copy of my new Reactions book. It won't be in stores until probably October, but I have laboriously printed and glued up one precious copy.)

Award-Winning Fan Mail

There's fan mail and there's award-winning fan mail....

As much as I appreciate receiving them, and as much as I have a fragile ego in need of constant stroking, I don't normally write a blog post when I get an email from someone who enjoyed my book. But this one is special.

Here's the email I got, followed by the text of said award-winning fan letter.

Dear Mr. Theodore Gray,

   In December of 2016, I had submitted a letter to contest, called the National Letters about Literature Contest. Letters submitted to the contest were about a book that had  changed your life, mine was your book The Elements. At the beginning of March I received an email stating that my letter had won for the state of Nebraska in the high school level. As of today (April 23, 2017) I have not received any notification regarding my letter's status on the national level. I have attached the letter, in the hopes that you would enjoy reading it.

Thank you,

Matthew P. Heaney

I course I immediately replied that, why yes, I did enjoy reading it, and would he mind if I put it on my blog! Here it is in all its state-level award-winning glory:

Dear Theodore Gray,

            Your every word, your every personal anecdote in your book The Elements: A Visual Exploration of Every Known Atom of the Universe was an atom of solder that created for me a connection to my own life goals. My life is like an incomplete calculator: there is a battery with a copper wire connected to it, and a silicon circuit board. All I needed was some tin solder to connect that wire to the circuit board. The solder I needed was your book. As I was reading I gradually started to make connections. Your book brought back pieces of my past and connected them to the present. Soon after making these connections I would understand my life goal.

            In our seventh grade yearly book fair, my science teacher came up to me and pointed at your book. I skimmed though some of the first few pages and then rashly bought the book. At home after I read your precaution to not drop the book on my foot, I became confused with the names of groups in the periodic table. Although too technical for me to understand quantum mechanics, it became something of a challenge and although I did not comprehend it the first few times, I kept at it. Unfortunately, I eventually had to give up and move on to the elements.

            Needless to say I was happy once I got to hydrogen, since I actually understood some parts of it. My grandfather used to print off astronomy pictures of the day and he would show them to me. I was reminded of these pictures by your choice to use the Eagle Nebula in your representation of hydrogen. My first practical application occurred when I was able to find boron samples around my house – Silly Putty and a boron carbide lock. Now every page became a new discovery to me. With carbon you mentioned that diamonds could make your lip feel cold since it was such a good conductor of heat. When my mom got home that night I told her I wanted to make sure her ring had a real diamond in it. I later assured her that it was. With that success I decided to melt objects to get their base components.

            Farther into the book I started picking up on low melting point metals and how you had melted zinc down on the kitchen stove as a child from scrap zinc roof flashings. However, as you well know in the 21st Century, not as many roofing products are made of zinc, and unfortunately there are no scrapyards near my house. I began to look for expendable (or so I thought) objects that were in my house. The only way I would find out if they were zinc was if I melted them in a pot over the stove. My first choice was a monopoly character piece because they sure looked like zinc, but to my disappointment they would not melt despite my best efforts. I tried to do some level of research as to find distinct characteristics of zinc versus other similar metals, and fortunately I also discovered that zinc, when molten and in contact with water, explodes. My mom is not fond of explosions so I read further, searching for some other metal that I could melt.

            I came across gallium, but its lack of applications in household items precluded further experimentation. Zinc and gallium were a depressing no but tin proved to be the experiment! I wanted to make a cast of something out of clay, similar to the tin soldier you made, so I used clay to make a rough cast of my finger. I placed solder in this basic cast, closed up the hole with some more clay so I could lay the cast on its side, waited for it to dry, and put it in a heated oven. It did not take long for the clay to start popping and shooting shrapnel all throughout the oven. I quickly turned off the oven, and was disappointed when the cast had cooled off only to find that none of the solder had melted. For the third attempt since I had determined that clay would pop and explode if it got hot, I used aluminum foil. I folded and shaped the aluminum around a pencil, and removed the pencil, then put a plastic funnel at the top. You probably know where this was headed. First the plastic funnel melted, and second, my completely exposed hand was right below the melting plastic. I immediately stopped, once I felt the really hot sensation in my hand. I was lucky that only molten plastic touched it, as the burn would have been far worse had metal touched it. My singed fingers and the mess in the oven dictated no more experiments.

            With that I came to the conclusion you had the resources that I did not, so I decided to observe things. With consistency and dedication I began to notice everyday objects differently. Sometimes on occasion when there was a sample picture in your book similar to something I had seen in my life, questions would start popping up, “Is that really vaseline glass containing uranium or is it just dye? Does this magnet have samarium in it or not?” These questions satisfied my ever growing curiosity. I began to love verbalizing these questions and was always intrigued to find the answers. In high school chemistry class I soon learned to love the experiments even more, and I realized how I could answer some of these questions by performing experiments safely.

            Also in my chemistry class I started to reread your book. I started using your book for reference and answers to questions I had which developed skills to find the answers on my own. By my sophomore year I was asked the question what I wanted to be. In nothing short of an epiphany the skills I had developed, this mindset of asking questions, my constant longing for knowledge and an affinity to chemistry, all came together and my "calculator" gave me my answer: chemist. The word resonates in my head. The idea of working with elements, and compounds, finding out what makes them do the things they do, makes me elated.

            Now I could simply tell you that in that moment my brain released a good amount of dopamine and some oxytocin mixed in that made this feeling so amazing, but it probably has also a large amount of non-chemistry related reasons too. I am a junior, I love chemistry, and I plan to go to college and major in chemistry, and then work towards a doctorate. This accomplishment would make me the first person in my family with the title doctor to be in the research field. The book that I had bought 4 years ago is no longer in my possession as it had become so worn down that there was no binding left, and was just a pile of pages. I have since acquired two more copies of your book. Your book is iconic to me as it plays a constant role in my life. It consistently keeps me going and reminds me of what I want be every day. When I am a chemist your book will still be with me in my mind and in my hands, but not on my feet.


Matthew Heaney, Grade 11