Python: A "Toy" Language

Presentation at PyCon 2013, Santa Clara. This talk was unreviewed and scheduled in place of a talk by Audrey Roy Greenfeld who was unable to attend at the last minute. Watch video at https://www.youtube.com/watch?v=BWyDA5y6TIg

Transcript

1. Python: A "Toy" Language David Beazley (@dabeaz)
2. Is this about toy problems? def fibonacci(n): if n <= 2: return 1 else: return fibonacci(n-1) + fibonacci(n-2)
3. No, let's talk about kids... (oh no...)
4. An amazing science project Advanced Biology
5. An amazing science project Advanced Biology ... and Chemistry
6. An amazing science project Advanced Biology ... and Chemistry Machine Learning
7. An amazing science project Advanced Biology ... and Chemistry Machine Learning ... and Chemistry A natural hacking instinct
8. You Get to Build Things Diabolical block towers
9. You Get to Build Things A doghouse (for toy dog)
10. You Get to Build Things Or maybe a birdhouse... (for real birds)
11. Hacker Pro-Tip Kids are the ultimate excuse for buying "tools" - Drill press - Telescope - Magnifying glass - Catapult - Oscilloscope - Soldering Iron - Laser - Welding torch
12. 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.
13. Question: how do you get your kid to want to be a diabolical pirate scientist BDFL?
14. Question: how do you get your kid to want to be a diabolical pirate scientist BDFL? ... in space.
15. A thought: maybe I could make toys
16. A thought: maybe I could make toys with Python?
17. A thought: maybe I could make toys Python + Kids + Building Stuff == Fun with Python?
18. A thought: maybe I could make toys Python + Kids + Building Stuff == Fun (also good way to avoid working on book) with Python?
19. Yes, this book
20. Seriously though... Writing Python programs to make toys... well, yeah. Duh!
21. 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
22. 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
23. DIY CNC Milling • ShapeOko Project • 1-man project (Edward Ford) • Chicago area • Super cheap $ So, shortly after last PyCon, this caught my eye...
24. CNC Milling • Scary speed • Lot's of noise • Flying chips • Thrilling Danger! In a nutshell: Computer controlled whirling knives
25. 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...
26. DIY != Industrial
27. Kit Arrival
28. Just to be clear... ... I have never done anything with CNC ever. (I'm a software geek, what could possibly go wrong?)
29. Assembly
30. Assembly
31. Assembly
32. Assembly
33. Assembly
34. Assembly
35. Assembly
36. Assembly
37. Assembly
38. Assembly
39. Assembly
40. Assembly
41. Assembly
42. Assembly
43. Assembly
44. Assembly Curse Words Uttered: CNC Mill - 0 Stroller - 137 (Stroller cost more)
45. Hello World
46. Practical First Job
48. Lincoln Logs
49. Wood Train & Fire Truck
50. Ladder: For Fire Truck
51. Detachable Wing
52. Flying Wooden Train
53. Flying Wooden Train with Hidden Pirate Treasure Chest
54. Flying Wooden Train with Hidden Pirate Treasure Chest
55. 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."
56. 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"
57. Or maybe...
58. ... wait for it
59. A miniature bike shed!
60. Random Consequence... "Daddy, can you make something?"
61. Random Consequence... "Daddy, can you make something?" Actual meaning: Install a new iPad app. (I digress)
62. Electronics/Tech Stepper Motors (3) Arduino w/ Grblshield Laptop (USB)
63. 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
64. 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)
65. Whirling Knives You're in the physical world Plotting with 25000 RPM end mill
66. Physics • No instantaneous motion • Hardware limitations • Material properties (0,0) (50,10) (20,40) Accelerate Decelerate Accelerate Decelerate Accelerate Decelerate
67. Geometry Restrictions cutter (can't cut exactly into vertices)
68. It's Inexact There are real hardware "errors" • Wobble in rotary tools (runout) • Misalignment/centering issues
69. Materials Science Wood HPDE Plastic Acrylic Machinable Wax
70. A Science Experiment? Feed rates, rotational speed, cut depth, etc.
71. 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)
72. 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) ]
73. 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!
74. Programming Errors They take physical form!
75. Real Dangers Rotating Knives! • Drill through table • Jamming • Shattered End Mill • Harmonic vibration • Destruction A simple sign error can get interesting
76. Real Dangers Rotating Knives! • Drill through table • Jamming • Shattered End Mill • Harmonic vibration • Destruction A simple sign error can get interesting TDD?
77. Solution? IPython Notebook? Is there anything it can't do? Why not CAM?
78. Project: Marble Track Plot mathematical functions into curvy marble track f(x) = 30*sin(0.15*x)
79. Project: Marble Track Track Cross-section Top View Track Path Normal vector f'(x)
80. Demo : IPython Notebook
81. Demo : IPython Notebook
82. Demo : IPython Notebook
83. Demo : IPython Notebook
84. Milling
85. Milling
86. Milling
87. Milling
88. Milling
89. Rough Cut
90. Challenges • Exceptions are common • There's a "panic" button • Often stop/resume • Still working on software for it...
91. User Testing
92. Integration Testing
93. Variation Ripple Track
94. Future Direction? Resin Casting (Photos: Guerilla Guide to CNC)
95. Future Direction? Printed Circuit Boards?
96. Is There a Point? • CNC is a long-solved problem • CAD/CAM is long-solved • Why bother?
97. 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
98. 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
99. 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.
100. 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)
101. Bigger Point? "Every child is an artist. The problem is how to remain an artist when we grow up." - Pablo Picasso s/artist/hacker/
102. Final Comments • You can do this! • ShapeOko (http:/ /www.shapeoko.com) • Guerrilla Guide to CNC (http:/ /lcamtuf.coredump.cx/gcnc/) • Thanks! • Follow at @dabeaz