Hi all,
Using a Arduino UNO with MAX30102 with an SSD1306 OLED display module to display pulse and SPO2.
Having an error, there isn't anything being displayed onto the screen, nor is the LED on the sensor coming on.
My code was heavily inspired by: Open Source Pulse Oximeter for COVID-19 - Arduino Project Hub
The MAX30102 sensor in the above link has only 4 pins, but mine has 7 as attached in the photograph.
The SSD1306 is working fine, I have used the library example to check it.
code:
#include <Wire.h>
#include "MAX30105.h"
#include "spo2_algorithm.h"
#include "Adafruit_SSD1306.h"
MAX30105 particleSensor;
Adafruit_SSD1306 oled;
#define SCREEN_WIDTH 128 // oled display width, in pixels
#define SCREEN_HEIGHT 64 // oled display height, in pixels
#define oled_RESET -1 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, oled_RESET);
#if defined(__AVR_ATmega328P__) || defined(__AVR_ATmega168__)
//Arduino Uno doesn't have enough SRAM to store 50 samples of IR led data and red led data in 32-bit format
//To solve this problem, 16-bit MSB of the sampled data will be truncated. Samples become 16-bit data.
uint16_t irBuffer[50]; //infrared LED sensor data
uint16_t redBuffer[50]; //red LED sensor data
#else
uint32_t irBuffer[50]; //infrared LED sensor data
uint32_t redBuffer[50]; //red LED sensor data
#endif
int32_t spo2; //SPO2 value
int8_t validSPO2; //indicator to show if the SPO2 calculation is valid
int32_t heartRate; //heart rate value
int8_t validHeartRate; //indicator to show if the heart rate calculation is valid
void setup()
{
Serial.begin(115200); // initialize serial communication at 115200 bits per second:
oled.begin(display, 0x3C);
oled.setFont(Arial14);
// Initialize sensor
if (!particleSensor.begin(Wire, I2C_SPEED_FAST)) //Use default I2C port, 400kHz speed
{
Serial.println(F("Sensor not found. Please check Power"));
while (1);
}
particleSensor.setup(55, 4, 2, 200, 411, 4096); //Configure sensor with these settings
}
void loop()
{
//read the first 50 samples, and determine the signal range
for (byte i = 0 ; i < 50 ; i++)
{
while (particleSensor.available() == false) //do we have new data?
particleSensor.check(); //Check the sensor for new data
redBuffer[i] = particleSensor.getRed();
irBuffer[i] = particleSensor.getIR();
particleSensor.nextSample(); //We're finished with this sample so move to next sample
Serial.print(F("red="));
Serial.print(redBuffer[i], DEC);
Serial.print(F(", ir="));
Serial.println(irBuffer[i], DEC);
}
//calculate heart rate and SpO2 after first 50 samples (first 4 seconds of samples)
maxim_heart_rate_and_oxygen_saturation(irBuffer, 50, redBuffer, &spo2, &validSPO2, &heartRate, &validHeartRate);
//Continuously taking samples from MAX30102. Heart rate and SpO2 are calculated every 1 second
while (1)
{
//dumping the first 25 sets of samples in the memory and shift the last 25 sets of samples to the top
for (byte i = 25; i < 50; i++)
{
redBuffer[i - 25] = redBuffer[i];
irBuffer[i - 25] = irBuffer[i];
}
//take 25 sets of samples before calculating the heart rate.
for (byte i = 25; i < 50; i++)
{
while (particleSensor.available() == false) //do we have new data?
particleSensor.check(); //Check the sensor for new data
redBuffer[i] = particleSensor.getRed();
irBuffer[i] = particleSensor.getIR();
particleSensor.nextSample(); //We're finished with this sample so move to next sample
Serial.print(F("red="));
Serial.print(redBuffer[i], DEC);
Serial.print(F(", ir="));
Serial.print(irBuffer[i], DEC);
Serial.print(F(", HR="));
Serial.print(heartRate, DEC);
Serial.print(F(", HRvalid="));
Serial.print(validHeartRate, DEC);
Serial.print(F(", SPO2="));
Serial.print(spo2, DEC);
Serial.print(F(", SPO2Valid="));
Serial.println(validSPO2, DEC);
}
//After gathering 25 new samples recalculate HR and SP02
maxim_heart_rate_and_oxygen_saturation(irBuffer, 50, redBuffer, &spo2, &validSPO2, &heartRate, &validHeartRate);
printToScreen();
}
}
void printToScreen() {
oled.clear();
oled.setCursor(0,0);
if(validSPO2 && validHeartRate) {
oled.print(F("Pulse: ")); .println(heartRate, DEC);
oled.print(F("Oxygen: ")); oled.println(spo2, DEC);
} else {
oled.print(F("Invalid reading, please try again."));
}
}
Please advise.
Regards,
Taran