Python: A "Toy" Language

Transcript

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   Python: A "Toy" Language David Beazley (@dabeaz)

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   Is this about toy problems? def fibonacci(n): if n <=

   2: return 1 else: return fibonacci(n-1) + fibonacci(n-2)
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   No, let's talk about kids... (oh no...)

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   An amazing science project Advanced Biology

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   An amazing science project Advanced Biology ... and Chemistry

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   An amazing science project Advanced Biology ... and Chemistry Machine

   Learning
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   An amazing science project Advanced Biology ... and Chemistry Machine

   Learning ... and Chemistry A natural hacking instinct
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   You Get to Build Things Diabolical block towers

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   You Get to Build Things A doghouse (for toy dog)

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    You Get to Build Things Or maybe a birdhouse... (for

    real birds)
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    Hacker Pro-Tip Kids are the ultimate excuse for buying "tools"

    - Drill press - Telescope - Magnifying glass - Catapult - Oscilloscope - Soldering Iron - Laser - Welding torch
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    Hacker Pro-Tip Kids are the ultimate excuse for buying "tools"

    - Drill press - Telescope - Magnifying glass - Catapult - Oscilloscope - Soldering Iron - Laser - Welding torch You know, for kids. The big one. Yourself.
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    Question: how do you get your kid to want to

    be a diabolical pirate scientist BDFL?
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    Question: how do you get your kid to want to

    be a diabolical pirate scientist BDFL? ... in space.
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    A thought: maybe I could make toys

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    A thought: maybe I could make toys with Python?

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    A thought: maybe I could make toys Python + Kids

    + Building Stuff == Fun with Python?
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    A thought: maybe I could make toys Python + Kids

    + Building Stuff == Fun (also good way to avoid working on book) with Python?
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    Yes, this book

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    Seriously though... Writing Python programs to make toys... well, yeah.

    Duh!
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    Making Things There's a bit of "maker" movement going on

    - 3D Printing - Hacker spaces - Arduino, Raspberry Pi - DIY It's been on my mind - "Oh, that might be cool" However, I've never been that actively involved
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    Issue Drawing and clicking "print" is a big "meh." 3D

    printing seems just a bit too magical If machine breaks, could I figure out how to fix it? More enjoyment from figuring out how to do something than actually doing it
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    DIY CNC Milling • ShapeOko Project • 1-man project (Edward

    Ford) • Chicago area • Super cheap $ So, shortly after last PyCon, this caught my eye...
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    CNC Milling • Scary speed • Lot's of noise •

    Flying chips • Thrilling Danger! In a nutshell: Computer controlled whirling knives
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    CNC Milling • Scary speed • Lot's of noise •

    Flying chips • Thrilling Danger! In a nutshell: Computer controlled whirling knives It sounded perfect! You know, for kids...
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    DIY != Industrial

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    Kit Arrival

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    Just to be clear... ... I have never done anything

    with CNC ever. (I'm a software geek, what could possibly go wrong?)
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    Assembly

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    Assembly

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    Assembly

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    Assembly

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    Assembly

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    Assembly

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    Assembly

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    Assembly

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    Assembly

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    Assembly

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    Assembly

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    Assembly

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    Assembly

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    Assembly

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    Assembly

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    Assembly Curse Words Uttered: CNC Mill - 0 Stroller -

    137 (Stroller cost more)
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    Hello World

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    Practical First Job

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    None
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    Lincoln Logs

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    Wood Train & Fire Truck

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    Ladder: For Fire Truck

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    Detachable Wing

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    Flying Wooden Train

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    Flying Wooden Train with Hidden Pirate Treasure Chest

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    Flying Wooden Train with Hidden Pirate Treasure Chest

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    Flying Wooden Train with Hidden Pirate Treasure Chest "Kid, if

    this doesn't stop, I'm going to start making you write a requirements doc."
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    Flying Wooden Train with Hidden Pirate Treasure Chest "Kid, if

    this doesn't stop, I'm going to start making you write a requirements doc--in Docbook XML"
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    Or maybe...

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    ... wait for it

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    A miniature bike shed!

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    Random Consequence... "Daddy, can you make something?"

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    Random Consequence... "Daddy, can you make something?" Actual meaning: Install

    a new iPad app. (I digress)
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    Electronics/Tech Stepper Motors (3) Arduino w/ Grblshield Laptop (USB)

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    Software import serial ser = serial.Serial( '/dev/tty.usbmodem641', 9600) def command(cmd):

    ser.send(cmd.encode('ascii')+b'\n') resp = ser.readline() if resp != b'Ok\n': raise RuntimeError(resp) It's just serial ports... use pyserial Simple command/response protocol
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    GCode G1 Z10 G1 X0 Y0 G1 Z-2 G1 X50

    Y10 G1 X20 Y40 G1 X0 Y0 G1 Z0 Movement controlled by simple commands It's a lot like plotting/turtle graphics (0,0) (50,10) (20,40)
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    Whirling Knives You're in the physical world Plotting with 25000

    RPM end mill
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    Physics • No instantaneous motion • Hardware limitations • Material

    properties (0,0) (50,10) (20,40) Accelerate Decelerate Accelerate Decelerate Accelerate Decelerate
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    Geometry Restrictions cutter (can't cut exactly into vertices)

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    It's Inexact There are real hardware "errors" • Wobble in

    rotary tools (runout) • Misalignment/centering issues
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    Materials Science Wood HPDE Plastic Acrylic Machinable Wax

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    A Science Experiment? Feed rates, rotational speed, cut depth, etc.

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    CAM Software Maybe there's a reason why there's a whole

    industry of expensive "Computer Aided Manufacturing" Software Of course, there's a free Python one too... (I have not used it)
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    DIY CAM CNC is "simple" enough to write scripts part

    = [ (0, 0), (0, 44.175), (23.175, 44.175), (23.175, 37.175), (60, 37.175), (60, 44.175), (83.175, 44.175), (83.175, 0), (0,0) ]
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    DIY CAM Direct streaming of GCode command('F1000') for z in

    range(1,10): command('G1 Z-%s' % z) for x, y in part: command('G1 X%s Y%s' % (x,y)) command('G1 Z0') You'll see those whirling knives moving around!
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    Programming Errors They take physical form!

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    Real Dangers Rotating Knives! • Drill through table • Jamming

    • Shattered End Mill • Harmonic vibration • Destruction A simple sign error can get interesting
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    Real Dangers Rotating Knives! • Drill through table • Jamming

    • Shattered End Mill • Harmonic vibration • Destruction A simple sign error can get interesting TDD?
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    Solution? IPython Notebook? Is there anything it can't do? Why

    not CAM?
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    Project: Marble Track Plot mathematical functions into curvy marble track

    f(x) = 30*sin(0.15*x)
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    Project: Marble Track Track Cross-section Top View Track Path Normal

    vector f'(x)
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    Demo : IPython Notebook

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    Demo : IPython Notebook

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    Demo : IPython Notebook

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    Demo : IPython Notebook

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    Milling

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    Milling

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    Milling

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    Milling

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    Milling

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    Rough Cut

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    Challenges • Exceptions are common • There's a "panic" button

    • Often stop/resume • Still working on software for it...
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    User Testing

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    Integration Testing

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    Variation Ripple Track

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    Future Direction? Resin Casting (Photos: Guerilla Guide to CNC)

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    Future Direction? Printed Circuit Boards?

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    Is There a Point? • CNC is a long-solved problem

    • CAD/CAM is long-solved • Why bother?
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    Is There a Point? • CNC is a long-solved problem

    • CAD/CAM is long-solved • Why bother? Answer: It's every bit as fun as my first computer... Also $300
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    Is There a Point? • CNC is a long-solved problem

    • CAD/CAM is long-solved • Why bother? Answer: It's every bit as fun as my first computer... (and in 1978, programming was a solved problem). Also $300
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    Is There a Point? • CNC is a long-solved problem

    • CAD/CAM is long-solved • Why bother? Answer: It's every bit as fun as my first computer... (and in 1978, programming was a solved problem). Also $300 And nothing shouts out "fun" like a JCL script.
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     It's Supposed To Be Fun Why did you start using

     Python? ... it's okay to admit it. It was probably because it was fun. (if it's not fun, you're not doing it right)
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     Bigger Point? "Every child is an artist. The problem is

     how to remain an artist when we grow up." - Pablo Picasso s/artist/hacker/
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     Final Comments • You can do this! • ShapeOko (http:/

     /www.shapeoko.com) • Guerrilla Guide to CNC (http:/ /lcamtuf.coredump.cx/gcnc/) • Thanks! • Follow at @dabeaz