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UPGRADED VERSION!
In this project we only use the max30102 heart rate blood oxygen sensor module. Max30102 integrates a red LED and infrared LED, photodetector, optical device, and low-noise electronic circuit with ambient light suppression.
In the project, when you measure your heart rate and blood oxygen concentration, press the button and your current heart rate and blood oxygen concentration will appear on the OLED screen.
Happy New Year and Have fun with it.
► Code in GitHub (scheme and sketch): https://github.com/DKARDU/heartrateNbloodoxygen
► Components
The following parts were used in this project:
Arduino NANO, https://amzn.to/3ihYFBl
0.96" I2C OLED, https://amzn.to/3gTMZnW
Max30102 Heart Rate Sensor
Jumper wires, https://amzn.to/3jCHhZd
Breadboard, https://amzn.to/33yEavN
❤Subscribe It's Free https://bit.ly/2C6HdAg
Thanks for watching, Stay home and Be safe...Have a great day!
#Arduinoproject #ArduinoBloodOxygen #Howto #COVID19 #BloodOxygen #ArduinoHeartRate #HeartRate
How to Make Blood Oxygen & Body Temperature Measurement with MAX30102 Pulse Oximeter using Arduino:
#include "ssd1306h.h"
#include "MAX30102.h"
#include "Pulse.h"
#include <avr/pgmspace.h>
#include <EEPROM.h>
#include <avr/sleep.h>
// Routines to clear and set bits
#ifndef cbi
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#endif
#ifndef sbi
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#endif
SSD1306 oled;
MAX30102 sensor;
Pulse pulseIR;
Pulse pulseRed;
MAFilter bpm;
#define LED LED_BUILTIN
#define BUTTON 3
#define OPTIONS 7
static const uint8_t heart_bits[] PROGMEM = { 0x00, 0x00, 0x38, 0x38, 0x7c, 0x7c, 0xfe, 0xfe, 0xfe, 0xff,
0xfe, 0xff, 0xfc, 0x7f, 0xf8, 0x3f, 0xf0, 0x1f, 0xe0, 0x0f,
0xc0, 0x07, 0x80, 0x03, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00 };
//spo2_table is approximated as -45.060*ratioAverage* ratioAverage + 30.354 *ratioAverage + 94.845 ;
const uint8_t spo2_table[184] PROGMEM =
{ 95, 95, 95, 96, 96, 96, 97, 97, 97, 97, 97, 98, 98, 98, 98, 98, 99, 99, 99, 99,
99, 99, 99, 99, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100,
100, 100, 100, 100, 99, 99, 99, 99, 99, 99, 99, 99, 98, 98, 98, 98, 98, 98, 97, 97,
97, 97, 96, 96, 96, 96, 95, 95, 95, 94, 94, 94, 93, 93, 93, 92, 92, 92, 91, 91,
90, 90, 89, 89, 89, 88, 88, 87, 87, 86, 86, 85, 85, 84, 84, 83, 82, 82, 81, 81,
80, 80, 79, 78, 78, 77, 76, 76, 75, 74, 74, 73, 72, 72, 71, 70, 69, 69, 68, 67,
66, 66, 65, 64, 63, 62, 62, 61, 60, 59, 58, 57, 56, 56, 55, 54, 53, 52, 51, 50,
49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 31, 30, 29,
28, 27, 26, 25, 23, 22, 21, 20, 19, 17, 16, 15, 14, 12, 11, 10, 9, 7, 6, 5,
3, 2, 1 } ;
int getVCC() {
//reads internal 1V1 reference against VCC
#if defined(__AVR_ATmega1284P__)
ADMUX = _BV(REFS0) | _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1); // For ATmega1284
#else
ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1); // For ATmega328
#endif
delay(2); // Wait for Vref to settle
ADCSRA |= _BV(ADSC); // Convert
while (bit_is_set(ADCSRA, ADSC));
uint8_t low = ADCL;
unsigned int val = (ADCH << 8) | low;
//discard previous result
ADCSRA |= _BV(ADSC); // Convert
while (bit_is_set(ADCSRA, ADSC));
low = ADCL;
val = (ADCH << 8) | low;
return (((long)1024 * 1100) / val)/100;
}
void print_digit(int x, int y, long val, char c=' ', uint8_t field = 3,const int BIG = 2)
{
uint8_t ff = field;
do {
char ch = (val!=0) ? val%10+'0': c;
oled.drawChar( x+BIG*(ff-1)*6, y, ch, BIG);
val = val/10;
--ff;
} while (ff>0);
}
/*
* Record, scale and display PPG Wavefoem
*/
const uint8_t MAXWAVE = 72;
class Waveform {
public:
Waveform(void) {wavep = 0;}
void record(int waveval) {
waveval = waveval/8; // scale to fit in byte
waveval += 128; //shift so entired waveform is +ve
waveval = waveval<0? 0 : waveval;
waveform[wavep] = (uint8_t) (waveval>255)?255:waveval;
wavep = (wavep+1) % MAXWAVE;
}
void scale() {
uint8_t maxw = 0;
uint8_t minw = 255;
for (int i=0; i<MAXWAVE; i++) {
maxw = waveform[i]>maxw?waveform[i]:maxw;
minw = waveform[i]<minw?waveform[i]:minw;
}
uint8_t scale8 = (maxw-minw)/4 + 1; //scale * 8 to preserve precision
uint8_t index = wavep;
for (int i=0; i<MAXWAVE; i++) {
disp_wave[i] = 31-((uint16_t)(waveform[index]-minw)*8)/scale8;
index = (index + 1) % MAXWAVE;
}
}
void draw(uint8_t X) {
for (int i=0; i<MAXWAVE; i++) {
uint8_t y = disp_wave[i];
oled.drawPixel(X+i, y);
if (i<MAXWAVE-1) {
uint8_t nexty = disp_wave[i+1];
if (nexty>y) {
for (uint8_t iy = y+1; iy<nexty; ++iy)
oled.drawPixel(X+i, iy);
}
else if (nexty<y) {
for (uint8_t iy = nexty+1; iy<y; ++iy)
oled.drawPixel(X+i, iy);
}
}
}
}
private:
uint8_t waveform[MAXWAVE];
uint8_t disp_wave[MAXWAVE];
uint8_t wavep = 0;
} wave;
int beatAvg;
int SPO2, SPO2f;
int voltage;
bool filter_for_graph = false;
bool draw_Red = false;
uint8_t pcflag =0;
uint8_t istate = 0;
uint8_t sleep_counter = 0;
void button(void){
pcflag = 1;
}
void checkbutton(){
if (pcflag && !digitalRead(BUTTON)) {
istate = (istate +1) % 4;
filter_for_graph = istate & 0x01;
draw_Red = istate & 0x02;
EEPROM.write(OPTIONS, filter_for_graph);
EEPROM.write(OPTIONS+1, draw_Red);
}
pcflag = 0;
}
void Display_5(){
if(pcflag && !digitalRead(BUTTON)){
draw_oled(5);
delay(1100);
}
pcflag = 0;
}
void go_sleep() {
oled.fill(0);
oled.off();
delay(10);
sensor.off();
delay(10);
cbi(ADCSRA, ADEN); // disable adc
delay(10);
pinMode(0,INPUT);
pinMode(2,INPUT);
set_sleep_mode(SLEEP_MODE_PWR_DOWN);
sleep_mode(); // sleep until button press
// cause reset
setup();
}
void draw_oled(int msg) {
oled.firstPage();
do{
switch(msg){
case 0: oled.drawStr(10,0,F("Device error"),1);
break;
case 1: oled.drawStr(13,10,F("PLACE"),1);
oled.drawStr(10,20,F("FINGER"),1);
oled.drawChar(100,0,voltage/10+'0');
oled.drawChar(106,0,'.');
oled.drawChar(112,0,voltage%10+'0');
oled.drawChar(118,0,'V');
oled.drawStr(84,14,F("Display"),1);
if (draw_Red)
oled.drawStr(84,24,F("Red"),1);
else
oled.drawStr(84,24,F("IR"),1);
if (filter_for_graph)
oled.drawStr(108,24,F("Avg"),1);
else
oled.drawStr(108,24,F("Raw"),1);
break;
case 2: print_digit(86,0,beatAvg);
wave.draw(8);
print_digit(98,16,SPO2f,' ',3,1);
oled.drawChar(116,16,'%');
print_digit(98,24,SPO2,' ',3,1);
oled.drawChar(116,24,'%');
break;
case 3: oled.drawStr(30,9,F("Thanks for"),1);
oled.drawStr(30,20,F("subscribing"),1);
//oled.drawXBMP(6,8,16,16,heart_bits);
break;
case 4: oled.drawStr(28,12,F("OFF IN"),1);
oled.drawChar(76,12,10-sleep_counter/10+'0');
oled.drawChar(82,12,'s');
break;
case 5: oled.drawStr(0,0,F("BMP:"),1);
print_digit(25,0,beatAvg);
oled.drawStr(0,15,F("SpO2:"),1);
print_digit(25,15,SPO2);
oled.drawXBMP(106,8,16,16,heart_bits);
break;
}
} while (oled.nextPage());
}
void setup(void) {
pinMode(LED, OUTPUT);
pinMode(BUTTON, INPUT_PULLUP);
filter_for_graph = EEPROM.read(OPTIONS);
draw_Red = EEPROM.read(OPTIONS+1);
oled.init();
oled.fill(0x00);
draw_oled(3);
delay(3000);
if (!sensor.begin()) {
draw_oled(0);
while (1);
}
sensor.setup();
attachInterrupt(digitalPinToInterrupt(BUTTON),button, CHANGE);
}
long lastBeat = 0; //Time of the last beat
long displaytime = 0; //Time of the last display update
bool led_on = false;
void loop() {
sensor.check();
long now = millis(); //start time of this cycle
if (!sensor.available()) return;
uint32_t irValue = sensor.getIR();
uint32_t redValue = sensor.getRed();
sensor.nextSample();
if (irValue<5000) {
voltage = getVCC();
checkbutton();
draw_oled(sleep_counter<=50 ? 1 : 4); // finger not down message
//? : x>yxy=z:if(x>y)z=x;elsez=y
delay(200);
++sleep_counter;
if (sleep_counter>100) {
go_sleep();
sleep_counter = 0;
}
} else {
sleep_counter = 0;
// remove DC element
int16_t IR_signal, Red_signal;
bool beatRed, beatIR;
if (!filter_for_graph) {//
IR_signal = pulseIR.dc_filter(irValue) ;
Red_signal = pulseRed.dc_filter(redValue);
beatRed = pulseRed.isBeat(pulseRed.ma_filter(Red_signal));
beatIR = pulseIR.isBeat(pulseIR.ma_filter(IR_signal));
} else {
IR_signal = pulseIR.ma_filter(pulseIR.dc_filter(irValue)) ;
Red_signal = pulseRed.ma_filter(pulseRed.dc_filter(redValue));
beatRed = pulseRed.isBeat(Red_signal);
beatIR = pulseIR.isBeat(IR_signal);
}
// invert waveform to get classical BP waveshape
wave.record(draw_Red ? -Red_signal : -IR_signal );
// check IR or Red for heartbeat
if (draw_Red ? beatRed : beatIR){
long btpm = 60000/(now - lastBeat);
if (btpm > 0 && btpm < 200) beatAvg = bpm.filter((int16_t)btpm);
lastBeat = now;
digitalWrite(LED, HIGH);
led_on = true;
// compute SpO2 ratio
long numerator = (pulseRed.avgAC() * pulseIR.avgDC())/256;
long denominator = (pulseRed.avgDC() * pulseIR.avgAC())/256;
int RX100 = (denominator>0) ? (numerator * 100)/denominator : 999;
// using formula
SPO2f = (10400 - RX100*17+50)/100;
// from table
if ((RX100>=0) && (RX100<184))
SPO2 = pgm_read_byte_near(&spo2_table[RX100]);
}
// update display every 50 ms if fingerdown
if (now-displaytime>50) {
displaytime = now;
wave.scale();
draw_oled(2);
}
Display_5();
}
// flash led for 25 ms
if (led_on && (now - lastBeat)>25){
digitalWrite(LED, LOW);
led_on = false;
}
}
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