82°
Posted: June 1, 2018 Filed under: Art, Coding, Creations, Explorations, How-to, That Totally Worked Leave a commentThis is a 100% recycled yak fur story.
Molly asked me a thoughtful question while I was in the middle of something else and I said “Just a second, I need to rotate my brain.” A moment later, I said OK and she asked me if my brain was all rotated now. I replied, “Well, 82° out of 90°, close enough.” Molly quipped “And since when did you ever do things square?”
But then I nerdsniped myself. I started to wonder about 82° angles. If a polygon with 90° angles is a square, what sort of polygon do you get if you turn 82° at each corner? It’s not one of your basic shapes, because:
- 120° angles make a triangle (3 sides, since 360° ÷ 120° = exactly 3)
- 90º angles make a square (4 sides; 360° ÷ 90° = exactly 4)
- 82° angles make a ??? (?? sides; 360° ÷ 82° = 4.3902439024???)
- 72° angles make a pentagon (5 sides; 360° ÷ 72° = exactly 5)
It must be some kind of … star shape, 82 doesn’t go evenly into 360, which means that you’d have to spirograph-around the circle more than once to come back to where you started.
But what kind of star? How many points would there be on a star with 82° angles at each point? I decided that I had to know, and that I wanted to see what the star looked like, not just find out the numeric answer. The numeric answer is the GCD of 82 and 360, and I could figure that out, but then where’s my picture of the star? I decided to write a quick program to draw stars with angles of ‘N’ degrees at each corner, and to print out how many points there were on the star.
And what’s a quick way to write a program to draw connected lines at various angles? With Logo and turtle graphics, naturally. Luckily, I’ve already done some programming in Logo. Unluckily, it was back in the 1980s. But it’s like riding an (imaginary) bicycle, right? I was sure I could remember and pick it up again quickly. I also (correctly) guessed that there were probably Logo interpreters that ran in a web browser using Javascript. I chose this one, because it had handy examples and Logo language reference documentation built in: http://www.calormen.com/jslogo/
So ten minutes later, I had refreshed my Logo skills. Luckily, Logo is secretly sort of a dialect of LISP, and I’m very comfortable with LISP-like languages. Here’s the code I finally came up with:
to anglestar :angle clearscreen penup forward 150 pendown make "count 1 setheading :angle while (heading > 0) [ forward 200 right :angle setheading round modulo heading 360 make "count sum :count 1 ] forward 200 show :count end anglestar 82
Now experienced, professional Logo authors will notice that there’s a ’round’ in there. Why is that? If all these numbers are integers, why do I need to ’round’ the numbers at all? Well, I didn’t have it in there at first, and the program wasn’t stopping. At all. It’s because this particular implementation of Logo, in Javascript, uses Javascript floating point numbers for Logo numbers, and since “modulo” is a floating point division-remainder operation in Javascript, sometimes instead of coming back with an answer like 377 modulo 360 = 17, it was really doing something like 377.0 modulo 360.0, and coming back with an answer like 17.000001, because floating point math is way more complicated and hard that you might think. So after having this problem, and fixing it by inserting a ’round’ into the heading math, everything worked better. Here’s the output from N=82°
And it printed “180”, meaning that this is a 180-point star. Or, as Molly pointed out, more of a bike wheel than a star really. An imaginary bike wheel.
I decided to try other angles since I now had this great program. With N=80°, you get a nine-pointed star, because 80° x 9 = 720°, which is twice around the 360° circle:
And with N=81° you get a 40-pointed star:
Although as Molly pointed out, this one isn’t really a ‘star’, either. This one is more of an imaginary bicycle gear, a lot like this real 40-toothed bicycle gear:
So anyway, the answer to the original question, “How many points are there on a ‘star’ whose lines meet at 82° angles?” is …. 180. (And yes, the GCD of 82 and 360 is, in fact, 180!) But to figure it out my way, I had to refresh my 35-year-stale Logo skills, debug and code around a Javascript floating point math issue, and now the floor is totally, completely covered in yak fur.
Oh, and after all this, Molly very patiently re-asked me her original question again, and I answered her without yak-further delay.
Easter Egg Hunt 2017
Posted: April 17, 2017 Filed under: Creations, DIY, Explorations, Getting A Clue, That Totally Worked, Uncategorized | Tags: chocolate, colors, Easter, easter egg hunt, easter eggs, fonts, logic, puzzle, puzzle hunt, puzzles 2 CommentsOh, we love our Easter Egg hunts.
Oh, we love our Easter Egg hunts. As the girls (now age 14) have grown from little kids, to tweens, to actual teenagers, what started as a simple find-the-hidden-eggs game has grown right along side them; it’s now a full-on multi-stage puzzle hunt. 2014’s hunt involved complex interlocking rules. 2016’s hunt involved cryptography and QR codes. Now, here’s how 2017’s puzzle unfolded…
Simple
The rules were simple: each girl would be assigned a couple of colors, and each girl could pick up any egg she found once she was certain that the egg matched one of her colors. Easy, right? Further ‘simplifying’ things, I announced that I had placed one giant colored egg on a pedestal with each girl’s name (and one for the parents), so all they had to do was look at the pedestal with their name, and they’d see their first egg color. I showed them all a picture (below) of how nicely I had set it up, and how easy it was going to be.
But when we got outside to start collecting eggs… quelle surprise! The wind seemed to have blown the eggs off their pedestals! How ever would the girls know which color was theirs??
Luckily, each pedestal contained a set of instructions for figuring things out in case of just such an emergency:
The girls retreated to the kitchen to pencil-and-paper this problem. After a few minutes, they’d worked it out with Rebecca offering supportive coaching (but not giving away the answers even though she’s great at these puzzles). The girls hastened outside to each crack open their correct-color giant eggs.
Inside each giant egg was a message… and another, smaller egg.
Inside the smaller eggs was some chocolate, which was immediate consumed as much-needed brain fuel. And there were also some scraps of cut up paper with writing across them — clearly they needed to be reassembled. The girls hurried back inside, and taped the paper back together, revealing four trivia questions about opening magical doors. (Full credit here: Three of these riddles were written by Ryan O’Boyle for Veracode Hackathon 10 & 5/7ths. His riddles were great, and inspired me to add one additional one of my own.)
It just so happened that the team included a Tolkien expert (Norm), and several Harry Potter fans (everyone but me) so the answers were quickly found. Bonus points to Abby for remember the spell “Alohomora”, and to Eleanor for remembering that the Ministry of Magic’s phone booth code was “M A G I C” on the telephone dial — and then using the Phone app on her iPhone to look up what numbers that was.
But now what? The girls still needed to know what colors of eggs they each were looking for, and all they had were these trivia answers — definitely not colors. Well luckily the third giant egg, the one for the parents, contained a “Helpful, Quick, and Easy Egg Color Key!” with some hand-wavey formula clues on it about how to transform the trivia question answers into numbers.
By considering a=1, b=2, etc., and adding up the letters in each trivial answer (and after I fixed a typo..oops), the girls arrived at numeric values… but still no colors. It was more or less at this point that Eleanor started invoking the word “patricide” in her running commentary.
Working through the formulas provided on the key, the girls had figured out that the variables k=112, j=250, x=147, and y=248, so, again, they had some numbers, but no colors. The key said that one color was y,y,x and the other color was k,j,k.
“But how are those colors?”, Rebecca asked, and there was a moment of silence.
“HEX CODES!” Eleanor exclaimed, and the chase was back on! Using an Internet color code converter, the girls converted 248,248,147 into yellow, and 112,250,112 into green. Colors at last!
Now with each of the girls knowing exactly which egg colors were theirs, they scooted out to the yard. Within just a few minutes, they’d found all of the (poorly) hidden eggs, collected them, and returned to the kitchen inside to savor the chocolate goodies within.
Then came the screams.
Then came the screams. For inside each egg not only was there a tasty bit of chocolate, but also… more sliced up message fragments. There was clearly another part of the puzzle. Madly, the girls sorted out all the pieces and assembled them:
The team stared at this for a while, and then started discussing the fonts: Papyrus, then a font that no one knew the name of, then Times, Comic Sans, and Helvetica (with a quick argument about Arial… ending with “Well, young lady, in this house, we use Helvetica!”). Could the five-letter word that the clue was asking for be made from the initials of the fonts? P_TCH? PATCH was considered for a minute, but when the girls hit on PITCH, the hints about “pining”, “note”, and “curveball” all clicked!
Using PITCH, they completed the partial URL and typed in http://tinyurl.com/2017EGGPITCH What came up at that URL was a photograph of the front of the house, with a big green arrow.
The girls practically flew out the front door, flipped over the flowerpot in the picture, and were rewarded with a glass jar filled with glittery treasure eggs, yet more chocolate, and a note saying VICTORY! CONGRATULATIONS on SOLVING the 2017 Easter Egg Hunt!
Happy congratulations were shared all around, and everyone enjoyed some of their hard-won chocolate.
With the puzzles finally solved, and chocolate fully secured, Eleanor finally stopped repeating the word “patricide” over and over, which she’d started saying nearly an hour before.
For the record, the total elapsed time was 56 minutes, 42 seconds — including the time it took for me to fix the typo in the math key (oops), and the time that Eleanor spent repeating the word “patricide”.
Maybe next year I’ll start making the puzzles hard.
#68: Clearway, For Inventing CDN
Posted: July 13, 2016 Filed under: Coding, Creations, Explorations, Getting A Clue, Reflections, That Totally Worked, Uncategorized | Tags: cdn, clearway, firesite, invention, inventions, patent, patents, startups Leave a commentBear with me here, because about 200 words from now I’m going to make a huge brag that I hardly ever talk about these days. OK, thanks. Let’s go:
In January 2001, “Web Hosting Magazine” published their “Top 100 Awards” issue.
Clearway Technologies, a company that I founded, shared an award for “Fastest Growing New Market: CDNs”. C.D.N. stands for “Content Delivery Network”, a system of helping deliver web pages, images, and videos faster over the Internet; the CDN that some people may be familiar with today in 2016 is Akamai, but back in the 2000’s, there were half a dozen CDN companies, all trying to get a slice of the CDN revenue pie.
On pages 42-43, Clearway, SolidSpeed, Speedera, EpicRealm, and Akamai were all called out for awards #5, 6, 7, 8, and 9, in the overall CDN area, and for developing this hot new marketplace.
And then, later on in the list of awards, we come to #68, given exclusively to Clearway, and to me, “For Inventing CDN”.
And you know what? They’ve got the facts right here. By the time Akamai was just barely getting started, I already had Clearway Technologies up and running, and we were already shipping our first CDN offering, and I’d already filed for the patent on our core technologies.
So while I’m a little too modest to be comfortable saying it, as far as I can tell, it’s true:
I invented the first CDN.
Now, while I do get to say that I invented the first CDN, “FireSite” and “FireSite.net”, I also have to say that I didn’t get rich from it. Clearway was initially a ‘bootstrap’ startup, and so grew very slowly at first. Here’s the entire company, in August 1996 doing our initial product launch at Macworld in Boston.
Later, we took in venture capital, and we grew Clearway to over 200 people. Here’s the team that helped do our ‘big’ launch at Networld/Interop 2000 in Atlanta.
So we grew the company and ultimately we sold it to Mirror Image Internet, another CDN company with complementary technologies and assets. And while Mirror Image is still around today, it, also, is not a success story. Mirror Image was never able to successfully monetize the union of their existing network infrastructure and Clearway’s advanced CDN technology, and so the company has never seen the growth that we hoped. (And thus I learned the meaning of the term “reverse stock split.”)
Other people have gone on to build bigger CDNs — most notably Akamai, who has become the dominant player in the CDN market, and they’re doing fine financially.
My original CDN patent (U.S. #5,991,809) was filed on July 25, 1996. In the U.S. the term of a patent is twenty years from the first priority date. That means my first CDN patent will expire in two weeks, on July 26, 2016. These twenty years have been a heck of a ride, and looking back, I’m proud of what I invented, and happy to see what it’s become.
-Mark Kriegsman, July 12, 2016.
Here’s the full text of what Web Hosting Magazine had to say about the invention of the CDN:
from Web Hosting Magazine, January 2001, page 77.
#68
Clearway
For Inventing CDNAkamai may think of itself as the grandfather of content-delivery network services, but let’s not forget the man who invented the idea: Clearway Technologies founder Mark Kriegsman.
Akamai’s business plan was entered into MIT’s annual $50,000 Entrepreneurship Competition in 1998, by which time Kriegsman had already received Patent #5,991,809 for his “web serving system that coordinates multiple servers to optimize file transfers.” The U.S. Patent Office abstract somewhat cryptically describes Kriegsman’s intervention as a “networked system consisting of one primary and at least one secondary server, both capable of storing static and dynamic content. In addition the primary server houses at least one look-up table, with which the system can use various criteria to search for specific data files and allocate transmission of each file between the primary and secondary servers based on these criteria.” (What can we say? It was 1997.)
Put in more modern terms, the patent covers intelligent redirection and intelligent optimization of compound web objects, such as HTML pages, JavaScript or streaming media metafiles.
So Akamai and Digital Island can sue each other all they want about patent infringements, but Mark– we know who really came first. Wink, wink ; )
Cautionary Tales of Power
Posted: November 27, 2015 Filed under: Coding, Creations, DIY, Explorations, Getting A Clue, How-to, Pearls of Folksy Wisdom, So that didn't work | Tags: arduino, blinky, DIY, fastled, fire, glow, glowy, LED, LEDs, light, power 2 CommentsWhen doing an LED electronics project, there seem to be three big “P”s that have to be tackled:
1. Pixels (which ones, how many, what configuration?),
2. Programming (what do I want, and how can I do that?), and
3. Power (how much, from where, and how do I distribute it?)
And people (by which I mean: perpetual newbies like me) tend to do them in that order: first wire up some pixels, then program them, then figure out how to power it all for real.
And of course, this often leads to a problem where you get stuck between steps 2 and 3, where you have your creation sort of up and running on the lab bench — but now there’s this little problem of how to power it, and you have to go back and rethink and rework other parts of the project to accommodate the power situation. So it’s worth planning for power from the start — which is easy to say, but hard to do!
What could possibly go wrong? (A list)
So what happens if you don’t plan for power? Well, here are some power problems that I have personally had. How many of these can you diagnose just from the description? (“Failure to plan” is a nice catch-all phrase here if you get stuck.)
- Hrm, now how do I get power all the way up there?
- Gee, that’s a long run of wire… but if I use fat wire, it’ll be expensive and heavy and cumbersome. Nah…
- I’ll use skinny wire, it’s much cheaper… Hey, why is it only reading 4v at the far end? And does anyone smell something burning?
- OK, I switched to thicker wire, and I’ll just re-use the power connectors from before. Holy cow now the connectors are getting hot!
- Fine, I’ll switch to these big thick nonpolarized connectors. Huh, that’s odd, it’s not working now. Does anyone smell something burning?
- For this other wearable project, I’ll use a simple battery holder and regular alkaline batteries… hey… why are the colors so ‘warm’.. no blue? And now no green, too…
- OK, switching power to one of those ’emergency phone chargers’ that takes AAs and puts out 5v from a USB socket. Hey! Why are the batteries dying so fast?
- OK, fine, I’ll switch to this lithium battery pack… hey, it said 5000mAh… so why did it stop powering my 5000ma project after only half an hour?
- How come my WS2811 project works fine from my computer, but then flickers like crazy when I power it from this cheap USB wall power adapter?
- For this big outdoor project, I’ll use this big, burly 12V lead-acid marine battery. Hey… how come it won’t hold a full charge after the first time I let the lights go all night?
- Everything was working fine yesterday, before last night’s rain!
- Everything was working fine yesterday in the cold and snow, so it should be working fine today now that it’s warming up, right?!
- I think I’m going to switch microcontrollers. The old one had a power regulator that could handle 12v input. Hey… do you smell something burning?
- Why is this power switch getting hot now? And why is it now totally stuck in the “on” position? And … do you smell something burning… again?
So: Plan For Power.
The lesson to learn here is that for basically any real project, calculate and plan the power first. Before you wire up any pixels. Before you write any code. Just stop for a minute and think about how much power you’re going to need, and where it has to come from, and where it has to go.
Use on-line calculators that will help you figure out how much power you’re going to need, and what gauge wire you’ll have to use given how long your cable runs are going to be. I also really like the “LEDstimator” app for iOS to help explore some “what-if” values for things like wire gauge. https://itunes.apple.com/us/app/ledstimator/id945794010?mt=8
And above all else… uh… wait… do you smell something burning?
FastLED for the Apple II: Hack to the Future!
Posted: February 16, 2015 Filed under: Art, Coding, Creations, DIY, Explorations, That Totally Worked, Uncategorized | Tags: APA102, Apple, Apple //e, Apple II, AppleII, arduino, art, blinky, CALL -151, DIY, DotStar, fastled, glow, glowy, LED, LEDs, light, LPD8806, retrocomputing, WS2801 6 CommentsThese days, I hack LEDs. I’m the co-author (with Daniel Garcia) of the FastLED library for driving tons of high speed LED pixels and strips using microcontrollers like Arduino and Teensy.
But back in the day, I hacked a lot of Apple II. I published a couple of shoot-em-up games (with Geoffrey Engelstein), all written in lovingly hand-crafted 6502 assembly language.
Finally I decided it was time to link the present to the past: to connect a hundred high-speed RGB LEDs to an Apple II, somehow, and ‘port’ our FastLED library to 6502 assembly language.
Well, I did it, and it works. My new creation, “FastLED6502”, can drive a hundred 24-bit RGB pixels at more than 30 frames per second from an Apple //e :
The Details
Here are the details of “FastLED6502”:
- “FastLED6502” is a lightweight port of FastLED’s core functions to 6502 assembly language for the Apple ][, Apple ][+, Apple //e, and Apple //gs.
- Supports APA102 / Adafruit DotStar LED strips, as well as LPD8806 and WS2801 (though those two are not fully tested yet).
- The LED strip is connected to the Apple II using the 16-pin DIP game port on the computer’s motherboard. The 9-pin DB joystick/mouse port on the back of the //c, //c+, and //gs cannot be used, as it lacks the TTL digital output signals needed to drive the LED strip.
- 24-bit FastLED Rainbow colors are included, along with FillRainbow, Random8 and a number of other useful functions from FastLED’s main library.
- Everything had to be re-written from scratch in 6502 assembly language. Luckily(?), I still remember how to do that.
- The assembly code knows the binary serial protocols for the APA102 (Adafruit DotStar), LPD8806, and WS2801 LED driver chips. Depending on which one you select, FastLED6502 transmits the LED colors in the correct protocol over the game port TTL digital output lines.
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Considering that the Apple II sports a 1MHz 6502 so slow that even a “NOP” takestwo cycles, overall performance is pretty good: more than 30 frames per second for a 100-pixel strip.
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Speaking of speed, or lack thereof, “three-wire” clockless LED strips such as the WS2811 NeoPixel are not supported now, nor will they ever be. The CPU is would need to be at least 20X faster to support them, and it isn’t. For that you want an Arduino or Teensy, and FastLED proper: http://fastled.io/
FastLED6502 at Veracode Hackathon 7
How’s it work?
So how does this all work? Well, you connect the CLOCK and DATA_IN pins from the LED strip to a couple of pins on your Apple II’s DIP game connector port, add power, and you’re ready to go. The Apple II’s game connector not only has inputs for joysticks, paddles, buttons, and so on, but it also has a few digital outputs — and that’s what FastLED6502 uses to deliver signals to the LED strip. On all the 16-pin DIP Apple II game ports (except for the //gs!), there’s even one pin that delivers a super-fast digital pulse; pin 5 is the C040STROBE line, which can pulse twice as fast as the other digital outputs. If you choose that for your CLOCK pin, the FastLED6502 code automatically shifts into high gear, and you get faster performance. FastLED proper does this, too, in a much fancier way; it’s amusing that ‘little’ FastLED6502 does some of this, too.
The Code
https://github.com/FastLED/FastLED/blob/FastLED3.1/extras/FastLED6502.s65And here’s the RainbowDemo.s65, as shown in video:
https://github.com/FastLED/FastLED/blob/FastLED3.1/extras/RainbowDemo.s65
This is Crazy
Fire2012: an open source fire simulation for Arduino and LEDs
Posted: April 4, 2014 Filed under: Art, Coding, Creations, DIY, Explorations, How-to, That Totally Worked | Tags: arduino, art, blinky, DIY, fastled, fiery, fire, glow, glowy, LED, LEDs, light 3 CommentsI’ve built and programmed a couple of different ‘fire’ simulations for Arduino and LEDs, and I’ve had numerous requests over the years to share the source code. I’ve always been happy to share my work; the holdup has been that before I share my code for the world to peer at, I like to clean it up a little. I like to give the code a clean shave and scrub under its fingernails before it steps out onto the wide open Internet where it might have an audience with Her Royal Majesty, The Queen of England. It could happen.
Anyway, I finally cleaned up the code for one of my simplest and most legible ‘fire’ simulations, and I give it to you, your Majesty, and everyone else, too. Here’s a video of the code in action on a 30-pixel strip of WS2812B LEDs (or maybe WS2811) and an Arduino. Source code link is below the video.
Full source code is here: http://pastebin.com/xYEpxqgq The simulation itself is only about 25 or 30 lines of code. It uses our (open source) FastLED library to drive the LEDs.
Discussion about the code and how to port it and use it are here on the FastLED discussion group on G+ https://plus.google.com/112916219338292742137/posts/BZhXE4cqEN4
Enjoy!
-Mark
If I’m confused, it must be playtime.
Posted: March 20, 2014 Filed under: Art, Coding, Creations, Explorations, Reflections, So that didn't work, That Totally Worked | Tags: arduino, fastled, learning, LED, LEDs, play Leave a commentSome things we try because we have a clear idea where we want to be and a clear idea how to get there.
Some things we try because we’re suddenly shocked to find that the heretofore completely impossible has suddenly and surprisingly come within practical reach.
And some things we try just to play, and to explore what if. We start with our heads full of simple ideas that turn out to be wrong, and we awkwardly replace them in torn out bunches with new confused half-understandings that, later, will let us reach something wholly unexpected.
I’m not sure which of these things in doing here, which means it’s probably that last one.
Hoop skirt — made with real hoops!
Posted: October 15, 2013 Filed under: Art, Creations, DIY, Explorations, How-to, That Totally Worked | Tags: costume, costuming, dress, duct tape, eak, eleanor, hoop, hoop skirt, hula hoops, skirt Leave a commentEleanor and I spent this weekend working on her Halloween costume. Part of what she planned was a ‘hoop skirt’, but as you can imagine no commercially available hoop skirt met her exacting standards of design and quality — and also my exacting budgetary requirements. Naturally, we decided to take the DIY route! And, we pondered, what goes into a hoop skirt? HOOPS, obviously!
We picked up a used dress at The Garment District (our local vintage/costume/cheapo clothing mecca), a set of three hula-hoops, and some leopard-print duct tape. The smallest hula hoop became the bottom (largest) hoop for the skirt; the other two had to be dramatically resized smaller (via pliers, dremel, duct tape). We started construction from the waist down, with a nylon web belt with a parachute snap buckle. From there, we hung each hoop with repositionable blue painters tape, and balanced each one until it was level. Then Eleanor secured each hoop in place at the right height with duct tape.
And presto! A hoop skirt made with real hoops! (and duct tape, of course!)
“Firelight” Lantern
Posted: February 11, 2013 Filed under: Art, Creations, Explorations, That Totally Worked | Tags: art, fire, flame, flames, lantern, LED, LEDs, light, lights Leave a commentThis past January (2013), I created “Firelight”, a lantern that shines with the light of a simulated fire.
The lantern contains over a hundred LEDs, a microcontroller, a battery pack, and custom software. The software monitors the remaining power in the batteries, and as the voltage slowly runs down, the flames burn lower, finally dying into embers as the batteries die.
I presented the Firelight lantern at the Veracode winter Hackathon, where I lit it, and then gently blew on the coals to kindle a flame. I’ve had a few requests to build more of these lanterns for other people, and I’m considering it, but haven’t made a decision yet. More pictures are here.
-Mark
The Lightning Tree: Halloween
Posted: November 1, 2012 Filed under: Creations, Explorations, That Totally Worked | Tags: arduino, art, blinky, DIY, fastspi, fastspiled, Halloween, LED, LEDs, light, TLT Leave a commentOver this past summer, I built “The Lightning Tree” — a 13-foot-tall steel and aluminum tree covered in hundreds of programmable LEDs. Normally, The Lightning Tree slowly cycles through animations depicting the different seasons of the year, but for Halloween I reprogrammed it full of wild purples and oranges, and planted it in our front yard!
It attracted and delighted kids and grown-ups throughout Halloween night, but the time the sun rose, it had disappeared, like all things ephemeral and magic. (To be clear: it disappeared in a good way, as Black Rock City does.)
blog.kriegsman.org 