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First light – five years later

Five years ago today I got my very first piece of LED art gear to light up for the very first time.

It was a Color Kinetics panel that you sent data to over ethernet, not an addressable LED strip & embedded microcontroller coding situation at all. The panel itself previously belonged to an LED art pioneer, “Frostbyte”, who had taken it with him on his desert adventures before his untimely and accidental demise. His old electronic gear was auctioned for charity, and without really knowing what I was getting in to, I bought this massive (28 pound!) metal box with 144 RGB LEDs in it, and the network controller to match.

Frostbyte lives

I could find no open source software to drive it, and owning the commercial sequencing/design package was out of my reach. For three years, the panel sat in my workroom idle and dark. But at some point, I found that the vendor had a simple free “test program” available, and I decided to see what I could do. Since the color data was sent from the test program to the panel over ethernet, I was able to capture the network packets, reverse engineer them, write my own code to talk directly to the LED panel, and TA-DA! First light!

But even with that one LED panel up and running, more than a year passed before I started learning how to use addressible LED strips and Arduino microcontrollers.  Another year after that, I had officially become ‘part of’ FastLED with Daniel Garcia.

And now?  Now I’ve created LED art myself, taken it on my adventures– desert and elsewhere, sold it and gifted it.  I’ve taught LED classes, and I’ve helped build an online community for thousands of FastLED users.  I’m not sure what I expected when I first bought that LED panel, but I don’t think it was all this great stuff.

So if there’s a lesson here, it might be this: If something intrigues you, step toward it.  You never know exactly where you’ll wind up, but the journey will be an adventure in the right direction.

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FastLED for the Apple II: Hack to the Future!

These 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.
  • 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.
  • 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/
I gave the code its public debut at Veracode Hackathon 7.  (The theme was “Cozy Cabin” — I don’t usually wear plaid.)
I don't usually wear plaid.

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

The code is in the “extras” directory here (and eventually on FastLED’s main branch, but not yet)
Here’s the FastLED6502.s65 source code itself:
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

Overall, this bit of code is completely nuts, and we don’t expect anyone to use it.  At all.  Ever.  Accordingly, we’re not going to really support it, either.  At all.  Ever.  It was a labor of love and a creation of pure modern retrocomputing insanity.  But here it is, in all it’s insane glory, “FastLED6502”.
And now, if you cut me, I’ll bleed 16,777,216 colors at thirty frames a second.

Fire2012: an open source fire simulation for Arduino and LEDs

I’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

 


What Dark, Light, and Solstice mean to an LED art hacker

We celebrated the winter solstice last night with friends and laughter. I wore a little pin with a circle of LEDs on it, animating a cycle of light and dark.

20131221-065918.jpg
I think that for lightbenders (LED art hackers) like me, like us, the winter solstice is actually a bit of a mixed blessing; I’m as eager as the next guy to start the slow journey back toward warmer weather, but given than our LED creations thrive in darkness, the arrival of the winter solstice means there will be fewer hours of darkness each night to illuminate with our creations.

Likewise the summer solstice marks the start of the shift away from the happy-go-lucky light-out-past-dinner-time days, but it also brings promise of a winter’s beautiful dark canvas, which we’ll light with our love and our craft.

Have a bright beautiful solstice, everyone. And if you keep your calendar that way, Happy New Year!


“Firelight” Lantern

This 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

Over 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.)