Bringing maker education and computational thinking to the classroom.
Heart Rate Monitor
The activity is targeted for grade 7, but could work for grades 5 to 8.
120 minutes (approximately 2 class periods)
Work in pairs
Students design and build a heart rate monitor using the gator:particle sensor, micro:bit, and gator:bit. Students explore how they can raise and lower their heart rate through different activities and what that means for how hard their heart is working. Students augment their heart rate monitor with additional signals such as when their heart rate reaches different thresholds. This can work in a life science unit looking at anatomy and physiology, a physical education class looking to integration computation, or in a STEM class where students build wearable technology.
micro:bit, heart rate, physical activity, sensors, middle school, coding
Students should have some experience programming the micro:bit. Provided they have worked through some of the tutorials on the MakeCode website they should be able to complete the activity.
Introduction / Motivation:
[Download an app on your smartphone and/or use your fitness watch, really anything that can track your heart rate]. How many of you have ever checked your pulse in gym class? Have you ever wondered why sometimes it feels like your heart is racing? Why do you think it was happening? [Hopefully at least a few students will be in agreement, offer up some anecdotes]. Well that’s one of the things I use my smart watch for. It lets me monitor my heart rate (how many times my heart beats per minute) and see how it changes throughout the day. What do you think happens to your heart rate throughout the day? [some possible students responses… stays the same, goes up if I have a test, goes up when I walk home, goes down I sleep at night]. We can actually build our own heart rate monitor and figure out what is happening.
Make sure you are familiar with the different capabilities of the gator:bit and micro:bit. The main ones to focus on here are the different ways to represent information using the 5 LEDS on the gator:bit controlled by pin P12, the speaker controlled by pin P0, and the 25 LEDs on the micro:bit itself (see Figure 1). In addition, make sure you are familiar with the gator:particle sensor and how to wire it (see Figure 2). There are three blocks for controlling the gator:particle (see Figure 3). The main thing to remember is to connect the ground wire first to prevent any incomplete circuits. Incomplete circuits can cause parts of the system to heat up.
Figure 1: Ways to use the gator:bit/micro:bit to represent information.
Figure 2: Wiring diagram for the gator:particle and an actual picture of the wiring.
Before the Activity
With the Students
Figure 4: Sequence of moves in MakeCode to add the gator:particle.
Figure 5: The actual sensing part of the sensor. Place your finger tip over this for the most accurate readings.
Figure 6: Sequence of moves in MakeCode to add the neopixel library