IoT Smart Wristband for आमाबुवा in Nepal: DIY Vital Signs Tracker Using ESP32

Commercial health watches are expensive and often feature complex touch screens that are difficult for older relatives to navigate.

This project shows how to build a simplified, wearable wristband that monitors vital signs, shows the data on a small display, and sends notifications over WiFi.

Core Sensors

1. Pulse & Blood Oxygen: The MAX30102 sensor uses red and infrared light absorption to measure blood flow, yielding heart rate (BPM) and blood oxygen levels (SpO2).
2. Skin Temperature: The MLX90614 is a non-contact infrared thermometer. Unlike contact thermistors, it measures surface skin temperature quickly and without physical contact.
3. Step Counter & Fall Detection: The MPU6050 3-axis accelerometer and gyroscope tracks sudden motion changes that could indicate a fall.

Designing for Elders

• Single-Button Interface: Avoid complicated swipe menus. Use a single large physical button to cycle between heart rate, temperature, and step count on the screen.
• Simple Enclosure: You can 3D print a basic casing or modify an existing watch strap to hold the components.
• Low Power consumption: Configure the microcontroller to run in light sleep, waking up to check sensors periodically to save battery.

Basic Sensor Interface Code

Here is how to set up the MPU6050 and MLX90614 on the I2C bus:

#include <Wire.h>
#include <Adafruit_MLX90614.h>

Adafruit_MLX90614 mlx = Adafruit_MLX90614();

void setup() {
  Serial.begin(115200);
  Wire.begin();
  if (!mlx.begin()) {
    Serial.println("Error connecting MLX90614 sensor");
  }
}

void loop() {
  float skinTemp = mlx.readObjectTempC();
  // Est. core body temperature from wrist surface temperature
  float coreTemp = skinTemp + 2.0; 

  Serial.print("Skin Temp: ");
  Serial.print(skinTemp);
  Serial.print(" C | Estimated Core: ");
  Serial.println(coreTemp);

  delay(2000);
}

Keeping It Water Resistant

Because this is worn on the wrist, it's susceptible to moisture from washing hands or sweat during the monsoon.

• Spray the soldered circuit board with a thin layer of conformal coating to protect against moisture.
• Seal the edges of your casing with silicone sealant, leaving only the optical sensor window exposed to touch the skin.