Sequencing and pattern recognition are fundamental skills in computing, essential for solving problems and creating effective programs. From deciphering changing light sequences to following step-by-step instructions in daily tasks, such as cooking or personal hygiene, these skills are ubiquitous. In this chapter, we explore how sequencing and pattern recognition play vital roles in programming with the micro:bit, using LED lights to display images and developing programs with MicroPython. By understanding these concepts, we lay the foundation for mastering computational thinking.
Different types of projects require different types of prototypes. For hardware products like cars, a physical prototype is necessary to determine materials, costs, and parts. In software development, the prototype is a working model of the software used to gather user feedback on its appearance and functionality.
Prototyping is crucial in software development to avoid releasing buggy software. Users expect a fully functional product upon release. There are two main types of software prototyping: evolutionary and throwaway.
This involves developing a complete prototype for user feedback. Based on the feedback, improvements are made and new prototypes are created until the final solution is reached. An example is a new game given to users for testing; feedback is used to improve and redevelop the game.
This involves developing small sections of the final solution and gathering feedback. The small prototype is then discarded. This method reduces the risk of needing major changes in the final solution. An example is releasing a section of a game for user testing and then using the feedback to develop a new prototype.
In programming, moving from block-based to text-based coding involves recognizing patterns. For example, the MakeCode block to show a heart icon translates to the MicroPython code display.show(Image.HEART)
. Similarities in terms like "show" and "heart" help in understanding both types of code.
When comparing MakeCode and MicroPython for displaying a happy face when button A is pressed, similarities include:
if button_a.is_pressed():
).Pattern recognition within a single language, like MicroPython, allows you to modify code easily. For instance, to display a different icon when button B is pressed, you can copy and edit the existing code for button A, changing references from A to B and updating the image.
Flowcharts for these programs also show patterns, with decision blocks checking button presses and corresponding outputs. Placing flowcharts side by side highlights these similarities and patterns.
In the previous theme, patterns were identified between block-based programming in MakeCode and text-based programming in MicroPython. Similarly, patterns can be observed between text-based languages like MicroPython and Python. For example:
print()
function is used to output text.display.scroll()
function is used to output text.Both functions use brackets and quotation marks to define the text to be output, indicating that the content is a string.
Patterns can also be found in flowcharts. Flowcharts help predict outcomes by following the sequence from top to bottom and understanding the symbols used for processes and outputs.
Example
A flowchart example can be represented in both Python and MicroPython to output numbers 1, 2, 3 with a 1-second delay between each. Similarities include:
sleep
to add a 1-second delay in both languages.Overall, both flowcharts and written programs follow a sequential order from top to bottom, which is crucial for the expected program output.
In programming, multiple inputs may be needed to trigger an output. For example, starting a light sequence might require both a button press and a sound sensor activation. Each input can be true or false.
Boolean operators (AND, OR, NOT) allow combining multiple inputs:
Flowcharts help visualize these conditions. For instance, a flowchart can depict the logic of pressing buttons to display faces.
Sub-Routines
Sub-routines are sections of code used multiple times, placed separately from the main code, and called by their name in the main flowchart.
If the A button is pressed OR movement is detected, a light sequence runs; otherwise, a sad face is displayed. The sub-routine "Light sequence" displays a large square, waits 1 second, displays a small square, waits 1 second.
Before creating a prototype program, a project plan is essential to outline what the program needs to achieve. This involves breaking down the program into smaller problems that need to be solved. For example, to create a program where an alarm activates upon pressing a button on the micro:bit, questions would include identifying the input button, defining the alarm sequence, and determining actions if the alarm isn't activated. A project plan ensures software development progresses smoothly, defining the expected functionality, required sections, inputs/outputs, and testing procedures to ensure the final product meets expectations.
Pattern recognition can also be applied to debugging program code by checking the sequence in a flowchart. For instance, in a flowchart that alternates between displaying shapes and waiting, you can identify the next steps in the sequence by following the pattern.
In the example of MicroPython code corresponding to a flowchart, comparing the sequence in the flowchart with the code can reveal errors. Highlighted sections in the code that do not match the flowchart indicate where the sequence is incorrect. Rearranging these sections can fix the program.
When debugging, other potential errors to check include:
from microbit import*
HAPPY
)If errors are present, the micro:bit will display a sad face and indicate the line of the error by scrolling it across the display.
To turn on a different LED, like the top-left one, you would need to adjust the program code accordingly.
You can create a specific pattern using the LED grid. Here's how:
For example, a pattern can be created by adding numbers to represent the LED states (9 for on, 0 for off). Adding colors to a grid can help visualize the pattern:
Ensure the brackets are correctly opened and closed in the code related to the LED lights. Flash the program to check that the rows of LEDs turn on as expected.
In the previous theme, you learned to display a single image on the micro:bit's LED display using 9 to turn on LEDs and 0 to turn them off.
A moving image is created by combining multiple image outputs in a sequence. For example, to display LEDs on the left-hand side followed by LEDs on the right-hand side, you need to create two image outputs in the program:
Image 2: 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
4 4 4 4 4 4 0 0 0 4 4 0 9 0 4 4 0 0 0 4 4 4 4 4 4
28 videos|17 docs|5 tests
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1. What is the difference between Evolutionary Prototyping and Throwaway Prototyping? |
2. How can pattern recognition be applied in the context of text-based programming languages? |
3. What is the logic behind AND, OR, and NOT operators in programming languages? |
4. How can project plans and test plans help in the development process? |
5. What are some common techniques for identifying errors and debugging in programming? |
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