Ben Nuttall - Raspberry Pi Foundation - Community Manager

1. Physical computing
with Raspberry Pi
Ben Nuttall
Raspberry Pi Foundation
UK Charity 1129409

2. Ben Nuttall
● Raspberry Pi Community Manager
● Based in Cambridge, UK
● Columnist on opensource.com
● @ben_nuttall on Twitter

3. Over 10 million Raspberry Pis sold

4. Over 15 million Raspberry Pis sold

5. Raspberry Pi Foundation
● Educational charity founded in
2009
● Incorporates:
– Raspberry Pi Trading Ltd
– Code Club
– CoderDojo
– Raspberry Pi Foundation North
America
● Trading profits fund education
programmes
raspberrypi.org/about

6. Our mission
“Putting the power of digital making into the hands of people all over the world”
So that people are:
● Capable of understanding and shaping an increasingly digital world
● Able to solve the problems that matter to them, both as makers and
entrepreneurs
● Equipped for the jobs of the future
raspberrypi.org/about

7. We do this by providing...
● Low-cost, high-performance computers
● Outreach and education programmes
● Free resources and teacher training
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8. Current models
● Raspberry Pi 3
● 64-bit quad-core ARMv8
@ 1.2GHz
● 1GB RAM
● $35
● Raspberry Pi Zero / Zero W
● 32-bit single-core ARMv6
@ 1GHz
● 512MB RAM
● $5 / $10
raspberrypi.org/products

9. Raspbian desktop
raspberrypi.org/downloads

10. Raspbian x86
rpf.io/x86

11. GPIO Pins – General Purpose
Input/Output

12. Physical computing
● Flashy lights
● Motors & robots
● Photo & video
● Sensors
● Internet of Things
● Home automation

13. GPIO
● 3V3, 5V
● GPIO, SPI, I2C, UART
● GPIO = variable 3V3 pinout.xyz

14. GPIO components

15. Add-on boards / HATs

16. GPIO with Scratch

17. Python - GPIO Zero
from gpiozero import LED
from time import sleep
led = LED(17)
while True:
led.on()
sleep(1)
led.off()
sleep(1)

18. Python - GPIO Zero
from gpiozero import LED
led = LED(17)
led.blink()

19. GPIO Zero supports...

20. GPIO Zero Device Hierarchy!

21. Multi-paradigm: procedural
from gpiozero import LED, Button
led = LED(17)
button = Button(4)
while True:
if button.is_pressed:
led.on()
else:
led.off()

22. Multi-paradigm: event-driven
from gpiozero import LED, Button
led = LED(17)
button = Button(4)
button.when_pressed = led.on
button.when_released = led.off

23. Multi-paradigm: declarative
from gpiozero import LED, Button
led = LED(17)
button = Button(4)
led.source = button.values

24. .value
>>> led = PWMLED(17)
>>> led.value
0.0
>>> led.on()
>>> led.value
1.0
>>> led.value = 0

25. .value
>>> led = PWMLED(17)
>>> pot = MCP3008()
>>> led.value = pot.value

26. .value
>>> led = PWMLED(17)
>>> pot = MCP3008()
>>> led.value = pot.value
>>> while True:
... led.value = pot.value

27. Source / Values
Output Device
.value
.values
.source
Input Device
.value
.values

28. Source / Values
Output Device
.value
.values
.source
Input Device
.value
.values

29. Source / Values
from gpiozero import LED, Button
led = LED(17)
button = Button(2)
led.source = button.values

30. Processing values
Output Device
.value
.values
.source
Input Device
.value
.values
function

31. Source tools
from gpiozero import Button, LED
from gpiozero.tools import negated
led = LED(4)
button = Button(17)
led.source = negated(button.values)

32. Combining values
Output Device
.value
.values
.source
Input Device
.value
.values
Source tool
Input Device
.value
.values

33. AND logic gate
from gpiozero import Button, LED
from gpiozero.tools import all_values
button_a = Button(2)
button_b = Button(3)
led = LED(17)
led.source = all_values(button_a.values, button_b.values)

34. Energenie

35. Energenie tortoise lamp
from gpiozero import Energenie, TimeOfDay
from datetime import time
lamp = Energenie(1)
daytime = TimeOfDay(time(8), time(20))
lamp.source = daytime.values

36. Supporting multiple pin libraries
● RPi.GPIO
● Implemented in C, current default
● Available in PyPI & apt repository (installed by default in Raspbian)
● RPIO
● Implemented in C, supports hardware PWM, supports Pi 1 only (dead project)
● Available in PyPI
● pigpio
● Python wrapper for C library, supports lots of protocols, runs as daemon, supports remote connections
● Available in PyPI & apt repository (installed by default in Raspbian)
● Native
● Pure Python, limited functionality, experimental
● Included in gpiozero source
● MockPin & MockPWMPin
● Pure Python, used in test suite
● Included in gpiozero source

37. pigpio - remote GPIO from Pi or PC

38. pigpio - remote GPIO from Pi or PC
from gpiozero import LED
from gpiozero.pins.pigpio import PiGPIOFactory
from signal import pause
factory = PiGPIOFactory('192.168.0.2')
led = LED(22, pin_factory=factory)
led.blink()
pause()

39. pigpio - remote GPIO from Pi or PC
$ export GPIOZERO_PIN_FACTORY=pigpio
$ export PIGPIO_ADDR=192.168.0.2
$ python3 led.py
from gpiozero import LED
from signal import pause
led = LED(22)
led.blink()
pause()

40. MockPin
$ GPIOZERO_PIN_FACTORY=mock python3
>>> from gpiozero import LED
>>> led = LED(22)
>>> led.blink()
>>> led.value
True
>>> led.value
False

41. MockPin
>>> from gpiozero import LED
>>> led = LED(22)
>>> button = Button(23)
>>> led.source = button.values
>>> led.value
False
>>> button.pin.drive_low()
>>> led.value
True

42. pinout command line tool

43. Sense HAT
● Special made for Tim Peake's
Astro Pi mission
● Sensors, LED display &
joystick
● Great for science, games and
creativity
● Works on any Pi model
● Emulators also available
raspberrypi.org/products/sense-hat

44. Sense HAT

45. Sense HAT
>>> from sense_hat import SenseHat
>>> sense = SenseHat()
>>> sense.show_message(“Hello world”)

46. Sense HAT
>>> sense.temperature
25.0
>>> sense.humidity
45.0
>>> sense.accelerometer
{'pitch': 0.0, 'roll': 0.0, 'yaw': 0.0}
>>> sense.gyroscope
{'pitch': 0.0, 'roll': 0.0, 'yaw': 0.0}
>>> sense.orientation
{'pitch': 0.0, 'roll': 0.0, 'yaw': 0.0}

47. Sense HAT
from sense_hat import SenseHat
sense = SenseHat()
while True:
r = 255 * sense.humidity / 100
sense.clear(r, 0, 0)
pythonhosted.org/sense-hat

48. Astro Pi: Your code in space
astro-pi.org

49. Sense HAT Web Emulator
trinket.io/sense-hat

50. Sense HAT Desktop Emulator
sense-emu.readthedocs.io

51. Picamera
● 8 megapixels (v2)
– v1 was 5mpx
● Visible light & infra-red
versions available
● 1080p30, 720p60 and
VGA90 video
● Command line interface
and Python library
raspberrypi.org/products/camera-module-v2

52. Picamera - capture
from picamera import PiCamera
from time import sleep
camera = PiCamera()
camera.start_preview()
sleep(3)
camera.capture('/home/pi/Desktop/image.jpg')
camera.stop_preview()

53. Picamera – record video
from picamera import PiCamera
from time import sleep
camera = PiCamera()
camera.start_preview()
camera.start_recording('/home/pi/video.h264')
sleep(10)
camera.stop_recording()
camera.stop_preview()

54. Picamera + GPIO push button
from picamera import PiCamera
from gpiozero import Button
camera = PiCamera()
button = Button(17)
camera.start_preview()
button.wait_for_press()
camera.capture('/home/pi/Desktop/image.jpg')
camera.stop_preview()

55. Picamera image effects
from picamera import PiCamera
from time import sleep
camera = PiCamera()
camera.start_preview()
for effect in camera.IMAGE_EFFECTS:
camera.image_effect = effect
camera.annotate_text = effect
sleep(1)
camera.stop_preview()

56. Picamera image effects

57. Web Streaming
github.com/waveform80/pistreaming

58. Picamera + OpenCV
pyimagesearch.com

59. Google AIY Projects kit
● Free with The MagPi #57
● Now available to buy
● Google Voice HAT + speaker
● Google assistant
● Write code to process custom voice
commands
– “Lights on”
– “Robot go forward”
– “Take a picture”
aiyprojects.withgoogle.com

60. Mythic Beasts Pi Cloud
● Raspberry Pi 3 in the cloud a data centre
● NFS filesystem (no SD card)
● SSH into a Pi in minutes
mythic-beasts.com

61. The MagPi
● Community magazine established in
2012 (as free PDF download)
● Now the official Raspberry Pi
magazine
● Paper copies on sale in UK/US
shops and online
● Still a free PDF download
● Occasionally comes with a free
computer or other giveaway
● Book series (buy or download for
free)
raspberrypi.org/magpi

62. How you can get involved...

63. Raspberry Jam
● Independently organised
community events
● Family-friendly
● Mix of meetup / conference /
workshop styles
● Raspberry Jam Guidebook and
more resources available
● Contact me about setting one up!
raspberrypi.org/jam

64. Raspberry Jam near you?
raspberrypi.org/jam

65. Raspberry Jam big birthday weekend
rpf.io/bday

66. Code Club
● Free volunteer-led after
school clubs for children
aged 9-13
● Projects provided using
Scratch, HTML and Python
● Training and support
provided for volunteers
● Help translating materials
codeclubworld.org

67. CoderDojo
● Free volunteer-led youth
clubs for under-18s
● Informal, lots of variety
● Resources online
coderdojo.com

68. Raspberry Pi booth
● Booth #41
● Behind the registration desk
● Come say hi!
● Ask questions
● Tell me about your projects
● Find a Raspberry Jam near
you – or help set one up

69. Physical computing
with Raspberry Pi
Ben Nuttall
Raspberry Pi Foundation
UK Charity 1129409