Teaching Teens Physical Computing
with the Raspberry Pi

Eric and Hayden

LowVoltageLabs.com

Why teach computing to kids and teens?

Early 80s - learn to program

This was the app store

What tools?

Why the Raspberry Pi?

• Community
• Foundation supporting education
• Resources
• Inexpensive $35
• Ran full OS - Linux!
• GPIO - connect to the real world again

Lesson Plan

• Raspberry Pi Setup

• Programming the GPIO with scratch

• Fun with cameras!

• Python programming

Raspberry Pi Setup

                     Hardware

• Raspberry Pi computer with an SD card
• Monitor with a cable
• USB keyboard and mouse
• Micro USB power supply (2.5A)

                     Software

• Raspbian, installed via NOOBS                

Raspberry Pi connections

Connecting Raspberry Pi

Pi Desktop

Programs

Programming the GPIO

with scratch

• 1 x Solderless breadboard
• 4 x Male-to-female jumper leads
• 1 x Tactile push button
• 1 x LED
• 1 x Buzzer
• 1 x 330 Ohm resistor
• Low Voltage Labs GPIO reference board

GPIO Pins

Lighting an LED

LED controlled by GPIO

Scratch 2

Toggle a GPIO pin

Connect a button

Detect the button

Connecting a buzzer

Connect like an LED but without a resistor

Fun with cameras!

• 8 Megapixels
• Still images up to 3280 x 2464 pixels
• Video modes up to 1080p at 30fps

Connect the camera

• Power down the Raspberry Pi
• Connect the cable into the camera port

Enable the camera

Raspberry Pi Configuration

Enable the camera

Terminal

Camera commands

> raspistill -o pic.jpg

Take a picture - by default waits 5 seconds

> gpicview pic.jpg

View the picture

Advanced Camera commands

> raspistill

See all the command options

• Image size
• Image quality
• Timeout
• Timelapse mode
• Flip and rotate
• Effects

Camera effects

Image Effect mode options :

negative, solarise, sketch, denoise, emboss, oilpaint, hatch, gpen, pastel, watercolour, film, blur, saturation, colourswap, washedout, posterise, colourpoint, colourbalance, cartoon

> raspistill -ifx sketch -o sketch.jpg

Example:

More raspistill features

• Flip horizontal and vertical
• Time lapse mode
• Burst mode
• Exposure modes

Programming the GPIO

with Python

• Same original Raspberry Pi setup
• Low Voltage Labs Traffic Light

Connect the Traffic Light

Starting Python

Python start a new project

Python shell on the left

Click on File -> Then New File to create a

project on the right

Python traffic light programming

 from gpiozero import TrafficLights

Setup the GPIO

 lights = TrafficLights(9, 10, 11)

Setup the traffic lights:  red, amber, and green

  lights.blink()

Blink the traffic lights

Save and run the project

CTRL-S to save

Function key F5 to run

Python traffic light

  from time import sleep

Add delays

 while True:
    lights.green.on()
    sleep(1)
    lights.amber.on()
    sleep(1)
    lights.red.on()
    sleep(1)
    lights.off()

    sleep(1)

Make a light sequence loop

Thanks!

Raspberry Pi Foundation

http://raspberrypi.org/

• Creative Commons Images
• Creative Commons training materials

Hayden

Questions?

See us for a free

GPIO Plus reference

board and stickers

Eric and Hayden

@LowVoltageLabs

LowVoltageLabs.com