50 2 people counter

input.onButtonEvent(Button.A, input.buttonEventClick(), function () {
    basic.showNumber(Personenzähler)
})
input.onButtonEvent(Button.AB, input.buttonEventClick(), function () {
    Personenzähler = 0
})
let Personenzähler = 0
Personenzähler = 0
let komplett = 20
basic.forever(function () {
    if (grove.measureInCentimeters(DigitalPin.C16) < 10) {
        Personenzähler += 1
    }
    if (Personenzähler < komplett) {
        basic.setLedColor(0xff0000)
    } else {
        basic.setLedColor(0x00ff00)
    }
})

grove=github:calliope-edu/pxt-grove

Task @showdialog

Is the class complete? Use the ultrasonic sensor to check whether all the children are back in the classroom. Program a people counter to count the number of people entering the classroom.

Define variables

Create two variables at the beginning. One variable ||variables.peoplecounter|| for the number of people counted and one variable ||variables.complete||.

Define variables

Set the variable ||variables.personcounter|| to 0 at the start and the variable ||variables.complete|| to the number of classmates, e.g. 20.

Step 3

Permanently measure the distance. As soon as a person walks past the ultrasonic sensor and the distance falls below the value 10, increase the person counter by 1. Insert a ||logic.if/then|| branch into the ||basic.forever|| loop.

Compare value

Use a ||logic.logical comparison|| block in which the value of the ||grove.ultrasonic sensor|| is compared with the limit value, e.g. 10 cm. Note: In this tutorial, the ultrasonic sensor is already added and you can find it under the ||grove.grove|| blocks.

Increase variable

Increase the variable ||variables.personcounter|| by 1 if the value of the ultrasonic sensor is below 10, for example.

Evaluate values

If the people counter is smaller than the maximum number of students in the class, the LED lights up red, otherwise green. This time, insert another ||logic.if/then/else|| branch into the ||basic.forever loop||. Test if the variable ||variables.personcounter|| is smaller than the variable ||variables.complete||.

Define output

If the person counter is smaller than the variable complete, then ||basic.set the LED color|| to red. Otherwise to green.

Extension: Reset

Add the option to reset the people counter via ||input.A+B clicked|| so that the ||variables.peoplecounter|| can be restarted and restarted from 0.

Display variable

Finally, when ||input.button A|| is pressed, the LED matrix displays how many people have already been counted. Tip: Use the variable ||variables.peoplecounter|||

That’s it! ✨

Click on |Download| to transfer your program to your Calliope mini and test the people counter.