QUICK MATHS a game where its all about testing your mental calculations. Too slow and you lose, too fast you may make mistakes.

Step 0 – Pre Build Overview

  • use a Buzzer and OLED with the micro:bit.
  • use if-else statements to evaluate conditions.
  • create your own function on MakeCode.

Materials required

1 x BBC micro:bit
1 x Micro USB cable
1 x Buzzer
2 x F-F Jumper Wires
1 x OLED

Step 1 – Components

Connect 2 F-F jumper wires to the LED. The positive pin on the LED will connect to the yellow pin on the breakout board, while the negative one connects to the black pin. Plug the other end of the jumper wires to Pin 0.

Plug in the OLED as shown in the picture above. You can plug it into any of the three rows.

Step 2 – Pre-coding

We’ll need to add a package of code to be able to use our kit components. Click on Advanced in the Code drawer to see more code sections and look at the bottom of the Code Drawer for Add Package.

This will open up a dialog box. Search for OLED. Click on the search icon or press enter, then select the oled-ssd1306.

Step 3 – Coding Initial Screen

From the music section start the power up melody, this is the game’s introduction music.
After that, create a variable named started and set it to false, as the game has not started.
Finally, use the blocks under the Tinkercademy section to initialise the OLED and display the messages as shown in the picture above.

Step 4: Coding randomiser function

In this step, we will be randomising the questions that will be displayed.
Firstly, create a variable named answer. In this, we will store whether the answer should be true or false. We determine this by using the randomiser block under Math.

Next, we create 3 more variables – i1, i2 and a.
i1 + i2 = a this is an example of what these variables would be used for.
We then assign a random value from 1 to 9 to i1 and i2. The value of a would be set later.

After this, we create a variable name type, which will be used to store what type of question this is. (0: Addition, 1: Subtraction, 2: Multiplication, 3: Division)
type would then be given a random number from 0 to 3 using the block under math.
From here, there is an if-else statement that checks what type of question it is in order to generate an answer.

For Addition (0), if the answer for this is supposed to be true, we set a to the sum of i1 and i2. However, if this is supposed be false, we add 1 to correct answer.

For Subtraction (1), if the answer for this is supposed to be true, we set a to the sum of i1 and i2, afterwards we swap the values of a and i1. However, if this is supposed be false, we add 1 to i1.

For Multiplication (2), if the answer for this is supposed to be true, we set a to the product of i1 and i2. However, if this is supposed be false, we add 1 to correct answer.

For Division (3), if the answer for this is supposed to be true, we set a to the product of i1 and i2, afterwards we swap the values of a and i1. However, if this is supposed be false, we add 1 to i1.


Step 5: Coding Display function

In this step, we will be creating a function that displays the question onto the screen.
First, initialise the OLED as shown in the picture.
Next, we want to determine what sign to use thus create a variable named sign.
Afterwards set what the value of sign is by using an if else statement that checks what type of question it is.
(0: +, 1: -, 2: x, 3: /)
Now that we have that we would want to display the equation.
Under the OLED section, select the show string block and add the variables i1, sign, i2.
Now that the display function is done, call the function at the end of the randomise function, as you would want the question to be displayed after the values have been randomised.

Step 6: Coding the start action.

Now that we can randomise the questions it is time we start the game.
Firstly, create a start function. In this function, set the started value to true and call the randomise function. Afterwards, from the game section in advanced, add the set score block and set the value to 0.
Now that the function is complete, add the 2 button pressed blocks under the input section for both buttons A and B. In both blocks, create an if else statement to check if the game has not started and if it hasn’t call function start.

Step 7: Coding check function

Continuing from step 6, now we will be working on the part if the game has started.

Firstly, create 2 functions – correct and wrong. In the correct function, select the change score block from under the game section and change the score by 1. Next call the randomise function to get the next question and lastly start melody ba ding that repeats once for additional sound effects.

Moving on to the wrong function, start melody wawawawaa repeating once and show icon X to indicate that the player has chosen the wrong answer. Afterwards, initialise OLED as shown in image.
Lastly, we want to check the high score. Start off by creating a high score variable. Next create an if else statement as shown above, in this logic gate we are checking if the score is higher than the player’s high score if it is then the high score value will be set to the current score.
Not to forget, set the started variable to false as the game has ended.
Now that we have completed the correct and wrong functions, we need to call them as shown in the image.

Bonus step 8: Coding timer

By now you have a functioning game, but to make things most exciting we should add a timer. But before we dive into that there are a few things we have to do first.

Firstly, create an end function. In the function set up accordingly. This may seem familiar as this is the last part of the wrong function, you can replace that portion by calling this function. This function would be called again thus to prevent needing to reprogram it we can just call the function.

Next, create a slow function this would be called if the player does not answer in time. Create the blocks as shown in the image.

Following that, we have to create a new variable called time. Time stores when the player started a specific question. Afterwards, set its value to the running time (ms) block which can be found under the more tab of the input section.

Micro:bit does not have a built-in timer thus we would have to design one on our own by using what they offer. Now we know that time is when the player started the question, and running time is how long the program has been running, thus from this if we subtract them we get how long the player has spent on that question. For this game we only allow the player to have 2.5s (2500ms) for each question. Hence, they will lose if they are too slow.

Lastly, in the correct function add a block that sets the value of time to current running time. This is to refresh the starting time for a new question.

That’s it! You’ve officially completed this tutorial.