The document provides instructions for hands-on experiments with a Raspberry Pi, including connecting hardware components, navigating the command line interface, writing and running simple Python programs, and interacting with GPIO pins to control an LED and camera. Some key steps covered are logging into the Pi, exploring basic Python commands, blinking an LED using a Python script, taking photos with the Pi camera using Python, and triggering photos with a button press. The document aims to introduce basic Raspberry Pi and Python skills through a guided tutorial.

1. Hands on Raspberry Pi

2. Connect your Pi
- Raspberry Pi 2
- Micro SD card
- HDMI cable
- HDMIPi screen & power cable
- Mouse
- Keyboard
- WiFi dongle
- Raspberry Pi power cable (last)

3. Log in
Username: pi
Password: raspberry
Note: Password will not show while typing

4. Try the command line
Type the commands:
- ls
- ls -l
- pwd
- cd python_games
- ls
- cd

5. Boot to desktop
- Run the command startx
- Hit Enter

6. Open Python 3
Python is a programming language
IDLE is a Python application

7. Hello world
In the IDLE Python window, enter:
print(“Hello world”)
and hit Enter

8. Calculator
Try:
2 + 2
10 * 5
123 + 456

9. Variables
Try:
a = 1
b = 2
c = a + b
print(c)

10. Strings
Try:
name = “Ben”
print(“Hello ” + name)

11. Syntax errors
Try:
print(Hello)
print(“Hello)
print(“Hello’)

12. Types
Try:
age = 26
“My age is ” + age

13. Type casting
Try:
“My age is ” + str(age)

14. Loops
Try:
for i in range(10):
print(“Hello”)

15. Loops
Try:
for i in range(10):
print(i)

16. Exit IDLE
Close the IDLE window

17. GPIO pins

18. GPIO pins

19. Breadboard

20. Connect ground rail

21. Wire up LED to 3V3

22. Open Terminal

23. Create new folder
Type mkdir intro and hit Enter
This creates a new directory (folder) called
intro

24. Enter the folder
Type cd intro and hit Enter
“Change directory intro”
This enters the directory intro

25. Open IDLE as super user
In the Terminal window, run:
sudo idle3 &
This will open IDLE with super user permissions
- we need this to access GPIO pins
The ampersand (&) opens it in a new process

26. Open a new window
Go to File > New window

27. Save file
Go to File > Save
Save as led.py in your intro folder

28. Flashing LED program
from RPi import GPIO
from time import sleep
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
GPIO.setup(2, GPIO.OUT, False)
for i in range(10):
GPIO.output(2, True)
sleep(0.1)
GPIO.output(2, False)
sleep(0.1)

29. Move from 3V3 to GPIO 2

30. Run the script!
Press F5 to run the program

31. Add second LED

32. New file
Go to File > New window
Save as led2.py

33. Code for 2 LEDs
from RPi import GPIO
from time import sleep
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
red = 2
blue = 3
GPIO.setup(red, GPIO.OUT, False)
GPIO.setup(blue, GPIO.OUT, False)

34. Flash continuously
while True:
GPIO.output(red, True)
sleep(0.1)
GPIO.output(blue, True)
sleep(0.1)
GPIO.output(red, False)
sleep(0.1)
GPIO.output(blue, False)
sleep(0.1)

35. Make it stop!
Press Ctrl + C to force quit (it won’t ever end)

36. Shut down your Pi
Enter sudo halt in the Terminal
OR
Shut down from the main Menu

37. Connect your Camera

38. Boot the Pi and log in

39. Test the camera
Type raspistill -k and hit Enter
This starts the camera preview
Hit Ctrl + C to stop

40. Take a selfie!
Type raspistill -o image.jpg and hit Enter
raspistill is the command for using the camera
-o means “output”
image.jpg is the chosen filename

41. Check the photo is there
Run ls to see the photo is there
Run startx to boot to Desktop

42. Open File Manager

43. Open image
Double click image.jpg to view it

44. Open IDLE as root
Open Terminal
Open IDLE as root user
sudo idle3 &

45. New file
Go to File > New window
Save as camera.py

46. Take a selfie with Python
from picamera import PiCamera
from time import sleep
with PiCamera() as camera:
camera.start_preview()
sleep(5)
camera.capture('/home/pi/image2.jpg')
camera.stop_preview()

47. View the photo from File Manager
Notice the difference in resolution between the file taken
from the command line and from Python
This is due to default settings in raspistill and in Python
picamera
Resolution and other aspects are configurable

48. Connect a GPIO push button

49. Add the button to the code
from picamera import PiCamera
from time import sleep
from RPi import GPIO
button = 17
GPIO.setmode(GPIO.BCM)
GPIO.setup(button, GPIO.IN, GPIO.PUD_UP)
with PiCamera() as camera:
camera.start_preview()
GPIO.wait_for_edge(button, GPIO.FALLING)
camera.capture('/home/pi/image3.jpg')
camera.stop_preview()

50. Press the button to take a picture
Run the script with F5
Wait for the preview
Press the push button to take a picture

51. View the photo from File Manager

52. Add a loop
with PiCamera() as camera:
camera.start_preview()
GPIO.wait_for_edge(button, GPIO.FALLING)
for i in range(5):
sleep(3)
camera.capture('/home/pi/image%s.jpg' % i)
camera.stop_preview()

53. What’s the difference?
GPIO.wait_for_edge(button, GPIO.FALLING)
for i in range(5):
sleep(3)
camera.capture('/home/pi/image%s.jpg' % i)
camera.stop_preview()
for i in range(5):
GPIO.wait_for_edge(button, GPIO.FALLING)
sleep(3)
camera.capture('/home/pi/image%s.jpg' % i)
camera.stop_preview()

54. What can you do?

55. Raspberry Pi Resources

56. Raspberry Pi Camera Resources

57. Experiment time!
- Try combining buttons, LEDs, camera
- Different buttons for different actions
- 2 buttons to start/stop preview
- LED status
- What else is in your CamJam kit?
- Use your imagination!

58. Updating your SD Card
(you must be online)
sudo apt-get update
sudo apt-get upgrade

59. Installing software
sudo apt-get install tree
sudo pip install twython
sudo pip-3.2 install twython