Pulse Monitoring with RGB LED and Microcontroller – SCOPES-DF

Lesson Details

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Author

Syuzanna Martirosyan

Summary

In this lesson, students will explore the relationship between heart rate, physical activity, and emotions using a pulse sensor and an RGB LED. By integrating biology, physics, and programming, students will measure their pulse, analyze how physical exertion or stress affects heart rate, and modify a microcontroller-based system to display real-time feedback.

Through hands-on coding, students will customize the LED colors to represent different pulse rates and add personalized messages in Armenian when no pulse is detected. The activity encourages interdisciplinary collaboration, as it involves elements of science, computer programming, and physical education.

The lesson fosters critical thinking, problem-solving, and data interpretation, making learning both interactive and applicable to real-life health monitoring.

What You'll Need

Electronic Components.

  • Pulse Sensor (to detect heart rate)
  • Arduino Board
  • RGB LED (to visualize the pulse signal)
  • Resistors (220Ω for LED)
  • Wires (jumper wires for circuit connections)

Tools & Equipment:

  • Soldering Kit
  • Computer (for programming and visualizing data)

Software & Programming:

  • Arduino IDE (to write and upload the code)

 

Learning Objectives

  1. Understand the physiological function of the heart and how heart rate is affected by physical activity, emotions, and environmental factors.
  2. Measure and analyze heart rate using a pulse sensor and interpret real-time data.
  3. Communicate findings effectively through discussions, data interpretation, and reflections on how heart rate changes in response to various stimuli.
  4. Collaborate across disciplines by integrating science (biology & physics), computer programming, and physical education into a single project.

 

Reflection

This lesson was an exciting and interactive way to combine biology, physics, and programming. Students were fascinated by how they could measure their heart rate using a pulse sensor and visualize the data with an RGB LED. They actively participated in testing their pulse before and after physical activity and were eager to see how their heart rate changed.

Challanges

Some students struggled to get a stable pulse reading. To address this, I guided them on proper finger placement and sensor sensitivity.

A few found the coding part complex at first, especially understanding how the RGB LED changed color based on heart rate. However, as they experimented with the code, they gained confidence.

Since we couldn’t test the entire class, I worked with a small group and shared their results with others. Next time, I would plan for a larger-scale experiment.

Creativity

  • Students successfully modified the Arduino code, adding an Armenian message:

“Որտեղ է քո մատը?” (Where is your finger?) when no pulse was detected.

  • Some wanted to add a buzzer to alert when pulse rates were too high or low.

Collaborating helped students connect heart rate with physical activity and emotions.

The lesson showed how technology can be used in health monitoring, making it a real-world, interdisciplinary experience.

The project inspired discussions about wearable tech, fitness trackers, and medical devices.

 

The Instructions

Introduction 5 min

Ask a question “What happens to our heart when we run? Or when we’re nervous?”

Brief discussion to activate prior knowledge.

 

Demonstration 5 min

Show the pulse sensor and RGB LED setup.

 Explain each component and the goal: visualizing heart rate with color.

Connect the RGB LED:

  • Identify the Red, Green, and Blue (R, G, B) pins.
  • Use 220Ω resistors for each color pin.

 

Connecting Components 5 min

Guide students in connecting the sensor and LED to Arduino. See connection diagram below. Connect the Pulse Sensor to Arduino: VCC → Connect to 5V GND → Connect to GND Signal (S) → Connect to A0

See connection diagram below.

 

Uploading Testing Code 10 min

Students upload the sample Arduino code.

They test it by placing a finger on the pulse sensor and watching LED changes.

Upload and Test the Code:

  • Open Arduino IDE.
  • Upload the pulse detection code.
  • Observe how the LED changes color based on pulse rate:

If the pulse is more than 65- blue

if the pulse is less than then65- green

Coding 10 min

Ask students to customize the code—change LED thresholds.

Students will add a message in Armenian when no pulse is detected.

Where is your finger?

  • Encourage students to modify the code to display messages like “Where is your finger?” when the sensor is not detecting a pulse.
  • Test how exercise, excitement, or relaxation affects their pulse rate.

 

Reflection & Sharing 5 min

Small group discussions: “What did your heart do after activity?” “What does the color mean?”

Share creative modifications.

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