Helloeveryone, in today's pandemic the highly dangerous SARs COV2 (covid19) is a very deadly virus and mostly seen symptoms are fever, increase in heart rate, difficulty in breathing etc., and reading temperature is easy but heart rate detection is not available for everyone so I created this device which is helpful in detection of Heart rate.

*Watch the video till end like share and subscribe.*

Project Overview

The "Vita-Sign Monitor" is a portable diagnostic tool developed as a responsive solution for home-based health monitoring during the global pandemic. By utilizing Photoplethysmograms (PPG) technology, this device measures the minute changes in light absorption through the fingertip caused by blood volume pulses. Real-time data is processed by an Arduino UNO and displayed on a 16x2 Alphanumeric LCD, providing users with an immediate BPM (Beats Per Minute) reading. It is a critical exercise in analog signal amplification, peak-detection algorithms, and biometric data visualization.

Technical Deep-Dive

• The Physics of PPG (KY-039 Sensor):
  • IR Transmittance: The KY-039 sensor consists of a high-intensity Infrared (IR) LED and an IR phototransistor. When a finger is placed between them, the sensor measures the amount of light that passes through.
  • The Hemoglobin Signature: As the heart pumps, the volume of blood in the fingertip capillaries increases, absorbing more IR light. This creates a rhythmic "AC" signal on top of the steady "DC" tissue-absorption signal.
• Analog-to-Digital Conversion (ADC):
  • 10-Bit Sampling: The Arduino’s ATmega328P uses a 10-bit Successive Approximation ADC to convert the sensor’s analog voltage (0V-5V) into a digital value (0-1023).
  • Signal Normalization: Because the sensor output is highly sensitive to ambient light and finger pressure, the firmware must implement a Dynamic Thresholding logic—constantly recalculating the "Mean" value to identify the true peaks representing heartbeats.
• BPM Calculation Logic:
  • Inter-Beat Interval (IBI): The code measures the time between consecutive detected peaks in milliseconds.
  • Rolling Average: To prevent erratic displays caused by movement or noise, the system calculates the average of the last 10 IBI readings. The final BPM is derived using the standard formula: $BPM = 60000 / AverageIBI$.
• Display Interfacing (Parallel 8-bit):
  • The LiquidCrystal library manages the timing-critical 6-pin interface to the 16x2 LCD. A 10k Ohm Potentiometer is utilized as a voltage divider on the V0 pin to provide fine-grained contrast control, ensuring the biometric data remains legible in various lighting conditions.

Engineering & Operation

• Noise Suppression Strategies: The project highlights the necessity of Electrical Isolation. The IR sensor is highly susceptible to "flourescent flicker" noise from room lighting. The developer recommends using a high-value capacitor (e.g., 10µF) across the sensor’s power rails and ensuring the user’s finger is held steadily with a light, consistent pressure.
• Prototype Layout: Using a full-size breadboard allowed for a modular design, separating the high-current LCD backlight circuit from the sensitive analog sensor path. This layout minimizes "crosstalk" between the digital switching of the LCD and the analog readings.
• Fritzing Verification: Before assembly, the entire complex wiring harness was verified in the Fritzing environment. This ensured that no short circuits occurred between the 5V and GND rails, which is vital when working with human-contact biometric sensors.
• Pandemic Utility: Beyond personal interest, this project demonstrates how open-source hardware can be repurposed for Self-Monitoring. During periods of respiratory illness, tracking heart rate trends is a secondary indicator of physical stress and systemic inflammation, making this a valuable addition to a home health kit.

I have shown you how the project works once it has been coded I hope you will like the project, and basically we have used a heart rate sensor we take readings for some seconds and then it displays it on the lcd screen, its cool right to have your own heart rate detection device I have given the scheamatics for connections and my code as well.

In the scheamatics there are three pins for KY039 heart rate sensor ,connect the S pin to Analog pin 0; 5v pin to 5v pin on arduino; Gnd pin to Gnd pin on arduino ;

I hope you will be knowing how to connect the lcd screen to arduino as it is very easy thing.

Enjoy coding. :)

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Monitor your vitals with precision—harnessing IR technology for reliable heartbeat detection.