# The heart rate

Teaching goals:
Determine how often your heart beats per minute
Comparing heart rate under stress and rest
Programming loops with the Calliope
Using the Calliope mini to control the LED
Programming a queue with the Calliope mini

Material:
Computer with Internet access
Calliope mini
Worksheet on heart rate

1Clock I
How fast does your heart beat and does everyone’s heart beat at the same pace? Have you ever measured it or read it somewhere? Probably not. The best way to feel one’s pulse is with two fingers around the neck. Here you can feel the pulse very clearly. We clearly recognize that there always is a beat followed up by a break. To make this visible, we will now use the Calliope mini.

1.At the beginning you create a loop. This means that a command is executed again and again. You find the block in the category Control. Put together the blocks Start and Repeat indefinitely. Insert the turn LED on block from the section Action into the loop. What does the program do? You can write it down.

2. You have now told Calliope mini which task he should repeat indefinitely. Complete the program as follows. Find the matching blocks. Note what change you are observing.

3 What happens if you remove the"Wait ms 100" blocks?

4. Think about how you can change the beat. Change the program accordingly and try it out.

5. Change the color of the LED.

6. save your result with the name "beat" and save it on the Calliope mini. Try it out.

2Clock II
We now want to investigate the heart as the metronome. Our Calliope mini helps us to visualize and compare the pulse.

1. Now we want you to check your heart rate. Download the program "clock I" onto your Calliope mini. What happens if you press button A? What happens when you press button B?

2. Now change the clock frequency and simultaneously feel your heart rate until both beat identically. Compare your Calliope mini beat to that of your classmates.

3. Find a partner. With a Calliope mini, leave the beat unchanged. Do 10 squats and repeat the experiment from task 1 with the second Calliope mini. Then compare the two heart rates with each other. What do you notice?

This text is published under a CC BY-NC 4.0 license. It was originally published in German by Rolf Maroske and translated into English by the Calliope team.