How to Use (ECG) AFE with HR Detection AFE: Examples, Pinouts, and Specs

The MAX30003 is an Analog Front End (AFE) designed by Analog Devices for Electrocardiogram (ECG) applications. It features heart rate (HR) detection capabilities, making it an ideal choice for medical and fitness devices. The MAX30003 amplifies and filters the small electrical signals generated by the heart, making them suitable for further processing and analysis.

• Wearable health monitors
• Fitness trackers
• Medical diagnostic equipment
• Remote patient monitoring systems
• Research and development in biomedical engineering

1. Power Supply: Connect the VDD pin to a stable power supply within the range of 1.1V to 1.3V. Connect the GND pin to the ground of the circuit.

2. ECG Inputs: Connect the IN+ and IN- pins to the electrodes placed on the patient's body. Ensure proper placement to get accurate ECG readings.

3. Right Leg Drive: Connect the RLD pin to the right leg electrode to improve common-mode rejection and reduce noise.

4. Clock and SPI Interface: Connect the CLK pin to a clock source. Use the CS, SCLK, MISO, and MOSI pins to interface with a microcontroller via SPI.

5. Interrupt and Reset: Use the INT pin to receive interrupt signals from the MAX30003. Connect the RST pin to a reset control line.

• Electrode Placement: Proper placement of electrodes is crucial for accurate ECG readings. Follow medical guidelines for electrode placement.
• Power Supply: Ensure a stable and clean power supply to avoid noise and inaccuracies in the ECG signal.
• Filtering: Implement additional filtering in the microcontroller to remove any remaining noise from the ECG signal.
• Calibration: Calibrate the system periodically to maintain accuracy.

#include <SPI.h>

const int CS_PIN = 10; // Chip Select pin for MAX30003

void setup() {
  Serial.begin(9600);
  pinMode(CS_PIN, OUTPUT);
  digitalWrite(CS_PIN, HIGH);
  SPI.begin();
  SPI.setClockDivider(SPI_CLOCK_DIV16); // Set SPI clock speed
  initializeMAX30003();
}

void loop() {
  // Read ECG data from MAX30003
  uint32_t ecgData = readECGData();
  Serial.println(ecgData);
  delay(1000); // Delay for 1 second
}

void initializeMAX30003() {
  // Initialize MAX30003 registers
  digitalWrite(CS_PIN, LOW);
  SPI.transfer(0x00); // Example register address
  SPI.transfer(0x00); // Example register value
  digitalWrite(CS_PIN, HIGH);
}

uint32_t readECGData() {
  uint32_t ecgData = 0;
  digitalWrite(CS_PIN, LOW);
  SPI.transfer(0x01); // Example command to read ECG data
  ecgData |= SPI.transfer(0x00) << 16;
  ecgData |= SPI.transfer(0x00) << 8;
  ecgData |= SPI.transfer(0x00);
  digitalWrite(CS_PIN, HIGH);
  return ecgData;
}

1. No ECG Signal Detected:

   • Solution: Check the electrode connections and ensure they are properly placed on the body. Verify the power supply and connections to the microcontroller.

2. Noisy ECG Signal:

   • Solution: Ensure a clean and stable power supply. Use proper shielding and grounding techniques. Implement additional filtering in the microcontroller.

3. SPI Communication Failure:

   • Solution: Verify the SPI connections and ensure the correct clock speed is set. Check the CS, SCLK, MISO, and MOSI connections.

• Check Connections: Ensure all connections are secure and correct.
• Verify Power Supply: Use a stable and clean power supply to avoid noise and inaccuracies.
• Use Proper Shielding: Implement shielding techniques to reduce electromagnetic interference.
• Calibrate Regularly: Periodic calibration helps maintain accuracy.

By following this documentation, users can effectively integrate the MAX30003 ECG AFE with HR detection into their projects, ensuring accurate and reliable ECG measurements.