49 1 Estimation game

let distance = 0
input.onButtonEvent(Button.A, input.buttonEventValue(ButtonEvent.Click), function () {
    distance = Math.round(grove.measureInCentimeters(DigitalPin.C16))
})
input.onButtonEvent(Button.B, input.buttonEventValue(ButtonEvent.Click), function () {
    basic.showNumber(distance)
})
basic.forever(function () {
    basic.showLeds(`
        . # # . .
        . . . # .
        . . # . .
        . . . . .
        . . # . .
        `)
})

grove=github:calliope-edu/pxt-grove

Estimation game @showdialog

Programme an estimation game that measures the distance between two objects. The Calliope mini measures the distance - in secret. You estimate the distance and the Calliope mini solves and displays the measured distance.

Task @showdialogue

Press button A to measure the distance and save it in a variable. Press button B to show the saved value of the variable on the display.

Buttons Add events

Insert the block ||input.on button A is clicked|| twice and change the button to B for one block. Tip: You can duplicate the block by right-clicking.

Define variable

To save the distance when the button is pressed and retrieve it later, create a ||variable.variable|| and name it distance.

Save distance

Use the ||grove.ultrasonic||| block to determine the distance. Note: In the tutorial, the ||grove.Grove extension|| is already integrated. You must first add it in the editor.

When the ||input.A|| button is clicked, save the measured value to the ||variable.set distance to|| block in the distance variable.

Save value

Now retrieve the saved value from the variable ||variables.distance|| and show it on the display when button B is pressed. To do this, use the block ||basic.show number|| and insert it together with the variable into the block ||input.on button B is clicked||.

Testing

Test your program! You will notice that the values of the ultrasonic sensor are quite long. The values are very precise and are not yet rounded. ||Math.round|| the value of the ultrasonic sensor, which you save in the variable ||variables.set distance to||.

Show question mark

Finally, let a ‘?’ appear permanently on the LED matrix. Draw a ? with the block ||basic.show leds||.

Done! 👏

Click on |Download|, test your programme on the Calliope mini and try to estimate the distance correctly!