Credit card-sized computers

Computers do not have to be big or expensive. A wide range of small and cheap computers are available. These small, credit-sized computers allow students to learn basics of computer programming and electronics, and make their own electronic devices easily. School children all over the world[1], such as US[2], UK[3][4] and Taiwan[5], are actively learning how to code and DIY their invention with these credit-sized computers.

Two popular credit-sized computers are Arduino[6] and Raspberry Pi[7]. They are suitable for code beginners to create their own DIY inventions.

Arduino

Arduino[6] is an open-source prototyping platform based on easy-to-use hardware and software. Arduino boards (Figure 1) are able to read inputs: light on sensor, a finger on a button, or a Twitter message; and turn it into an output: activating a motor, turning on an LED, publishing something online. You can tell your board what to do by sending a set of instructions to the microcontroller on the board.

https://www.arduino.cc/en/Main/ArduinoBoardUno
Figure 1: Arduino Board
(Source: https://www.arduino.cc/en/Main/ArduinoBoardUno)

You may wonder how school children who know nothing about programming can write complex instructions to control the board. Programming an Arduino is not especially difficult, you can use Arduino Programming Language [7] and the Arduino Software (IDE) [8]. The Arduino Software (IDE) (Figure 2) is easy-to-use for beginners, yet flexible enough for advanced users to take advantage of as well.

https://www.arduino.cc/en/Guide/Windows
Figure 2: Arduino IDE
(Source: https://www.arduino.cc/en/Guide/Windows)

For example, to blink an LED on the Arduino Board, you can first set up a circuit as shown in Figure 3:

https://www.arduino.cc/en/uploads/Tutorial/ExampleCircuit_bb.png
Figure 3: Circuit on Arduino Board
(Source: https://www.arduino.cc/en/uploads/Tutorial/ExampleCircuit_bb.png)

Next, to program it to blink, you only have to write the following codes in the Arduino Software: 

  void setup() {
    pinMode(13, OUTPUT);
  }
  void loop() {
    digitalWrite(13, HIGH); 
    delay(1000);            
    digitalWrite(13, LOW);
    delay(1000);
  }

By only these few lines of code, the LED on the Arduino Board blinks.

Does it sound too difficult for you? If you are looking for a more visual or easy method, especially for primary school students, a visual programming tool Scratch for Arduino (S4A) [9] is available as a groundwork for students or beginners programming an Arduino by drag and drop actions to create programs (Figure 4).

https://blog.arduino.cc/2015/05/11/scratch-extension-for-arduino/
Figure 4: S4A interface
(Source: https://blog.arduino.cc/2015/05/11/scratch-extension-for-arduino/)

To blink the LED like the example above, it can be done visually by placing action blocks together as shown in Figure 5.

http://www.instructables.com/file/FTLPMWGHCV97K30
Figure 5: Blink an LED using S4A
(Source: http://www.instructables.com/file/FTLPMWGHCV97K30)

Raspberry Pi

The Raspberry Pi[6] is a low cost, credit-card sized computer (Figure 6) that plugs into a computer monitor or TV, and uses a standard keyboard and mouse. It is a capable little device that enables people of all ages to explore computing, and to learn how to program in languages like Scratch and Python. It is capable of doing everything you'd expect a desktop computer to do, from browsing the internet and playing high-definition video, to making spreadsheets, word-processing, and playing games.


Figure 6: Raspberry Pi (Model: Raspberry Pi 2 B)
(Source: http://hken.rs-online.com/web/p/processor-microcontroller-development-kits/8326274/)

To blink an LED on the Raspberry Pi, an LED can be connected to a Raspberry Pi as shown in Figure 7.

http://simplesi.net/scratchgpio/scratchgpio-1st-project/
Figure 7: LED connected to Raspberry Pi
(Source: http://simplesi.net/scratchgpio/scratchgpio-1st-project/)

To program it, only a few lines of code are needed. 

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BOARD)
GPIO.setup(7, GPIO.OUT) 

while True:
  GPIO.output(7,True)
  time.sleep(1000)
  GPIO.output(7,False)
  time.sleep(1000)

If this sounds too complex, especially for primary school students, a visual programming tool Scratch[11] (with ScratchGPIO expansion package[12]) is available for programming the Raspberry Pi by drag and drop actions.

http://simplesi.net/scratchgpio/scratchgpio-1st-project/
Figure 8: Programming Raspberry Pi with ScratchGPIO
(Source: http://simplesi.net/scratchgpio/scratchgpio-1st-project/)

Invention for Schools using credit card-sized computers

With Arduino and Raspberry Pi, you can create electronic devices by yourself with simple programming instructions and user-friendly interfaces. You may use it to detect whether there is someone in the classroom, you may make a program to play your school song, you may create some education tools to assist teaching and learning... What else can you think of? Come and join the competition and make contribution to your school.

References

Use standard-compliant browswers such as Firefox (multiplatform) or Safari on Mac OS X for best experience.
Copyright © Department of Computer Science, Faculty of Engineering, The University of Hong Kong. All rights reserved.