Added chip temperature reading, applied potential bug fix, confined I…

…2C code to max30102.cpp.

"Parasetamol" suggested adding the MAX30102 die temperature reading. Why not, there is a register call for it, but keep it mind such a reading has _nothing_ to do with body temperature! Next, "williamesp2015" has raised an issue of initializing I2C twice: one in the main routine and one in max30102.cpp. Indeed, it may cause problems when custom Wire settings are defined. Thus, I have eliminated Wire call from the main routine. In addition, following "williamesp2015" I have changed the Wire clock speed to 400k.

RD117_ARDUINO.ino

@@ -30,13 +30,12 @@
 * ------------------------------------------------------------------------- */
 
 #include <Arduino.h>
-#include <Wire.h>
 #include <SPI.h>
 #include "algorithm_by_RF.h"
 #include "max30102.h"
 
 //#define DEBUG // Uncomment for debug output to the Serial stream
-#define USE_ADALOGGER // Comment out if you don't have ADALOGGER itself but your MCU still can handle this code
+//#define USE_ADALOGGER // Comment out if you don't have ADALOGGER itself but your MCU still can handle this code
 //#define TEST_MAXIM_ALGORITHM // Uncomment if you want to include results returned by the original MAXIM algorithm
 //#define SAVE_RAW_DATA // Uncomment if you want raw data coming out of the sensor saved to SD card. Red signal first, IR second.
 
@@ -82,17 +81,11 @@ void setup() {
   digitalWrite(sdIndicatorPin,LOW);
 #endif
 
-  Wire.begin();
-
 #if defined(DEBUG) || !defined(USE_ADALOGGER)
   // initialize serial communication at 115200 bits per second:
   Serial.begin(115200);
 #endif
 
-  maxim_max30102_reset(); //resets the MAX30102
-  delay(1000);
-
-  maxim_max30102_read_reg(REG_INTR_STATUS_1,&uch_dummy);  //Reads/clears the interrupt status register
   maxim_max30102_init();  //initialize the MAX30102
   old_n_spo2=0.0;
 
@@ -150,9 +143,9 @@ void setup() {
   dataFile.println(measuredvbat);
   dataFile.println(my_status);
 #ifdef TEST_MAXIM_ALGORITHM
-  dataFile.print(F("Time[s]\tSpO2\tHR\tSpO2_MX\tHR_MX\tClock\tRatio\tCorr"));
+  dataFile.print(F("Time[s]\tSpO2\tHR\tSpO2_MX\tHR_MX\tClock\tRatio\tCorr\tTemp[C]”));
 #else // TEST_MAXIM_ALGORITHM
-  dataFile.print(F("Time[s]\tSpO2\tHR\tClock\tRatio\tCorr"));
+  dataFile.print(F("Time[s]\tSpO2\tHR\tClock\tRatio\tCorr\tTemp[C]"));
 #endif // TEST_MAXIM_ALGORITHM
 #ifdef SAVE_RAW_DATA
   int32_t i;
@@ -178,9 +171,9 @@ void setup() {
   }
   uch_dummy=Serial.read();
 #ifdef TEST_MAXIM_ALGORITHM
-  Serial.print(F("Time[s]\tSpO2\tHR\tSpO2_MX\tHR_MX\tClock\tRatio\tCorr"));
+  Serial.print(F("Time[s]\tSpO2\tHR\tSpO2_MX\tHR_MX\tClock\tRatio\tCorr\tTemp[C]"));
 #else // TEST_MAXIM_ALGORITHM
-  Serial.print(F("Time[s]\tSpO2\tHR\tClock\tRatio\tCorr"));
+  Serial.print(F("Time[s]\tSpO2\tHR\tClock\tRatio\tCorr\tTemp[C]"));
 #endif // TEST_MAXIM_ALGORITHM
 #ifdef SAVE_RAW_DATA
   int32_t i;
@@ -233,6 +226,12 @@ void loop() {
   millis_to_hours(elapsedTime,hr_str); // Time in hh:mm:ss format
   elapsedTime/=1000; // Time in seconds
 
+  // Read the _chip_ temperature in degrees Celsius
+  int8_t integer_temperature;
+  uint8_t fractional_temperature;
+  maxim_max30102_read_temperature(&integer_temperature, &fractional_temperature);
+  float temperature = integer_temperature + ((float)fractional_temperature)/16.0;
+
 #ifdef DEBUG
   Serial.println("--RF--");
   Serial.print(elapsedTime);
@@ -241,7 +240,9 @@ void loop() {
   Serial.print("\t");
   Serial.print(n_heart_rate, DEC);
   Serial.print("\t");
-  Serial.println(hr_str);
+  Serial.print(hr_str);
+  Serial.print("\t");
+  Serial.println(temperature);
   Serial.println("------");
 #endif // DEBUG
 
@@ -290,6 +291,8 @@ void loop() {
     dataFile.print(ratio);
     dataFile.print("\t");
     dataFile.print(correl);
+    dataFile.print("\t");
+    dataFile.print(temperature);
 #ifdef SAVE_RAW_DATA
     // Save raw data for unusual O2 levels
     for(i=0;i<BUFFER_SIZE;++i)
@@ -331,6 +334,8 @@ void loop() {
     Serial.print(ratio);
     Serial.print("\t");
     Serial.print(correl);
+    Serial.print("\t");
+    Serial.print(temperature);
 #ifdef SAVE_RAW_DATA
     // Save raw data for unusual O2 levels
     for(i=0;i<BUFFER_SIZE;++i)
@@ -393,4 +398,3 @@ void blinkLED(const byte led, bool isOK)
   }
 }
 #endif
-

max30102.cpp

@@ -117,6 +117,14 @@ bool maxim_max30102_init()
 */
 {
   Wire.begin();
+  Wire.setClock(400000L); 
+
+  maxim_max30102_reset(); //resets the MAX30102
+  delay(1000);
+
+  uint8_t uch_dummy;
+  maxim_max30102_read_reg(REG_INTR_STATUS_1,&uch_dummy);  //Reads/clears the interrupt status register
+
   if(!maxim_max30102_write_reg(REG_INTR_ENABLE_1,0xc0)) // INTR setting
     return false;
   if(!maxim_max30102_write_reg(REG_INTR_ENABLE_2,0x00))
@@ -211,3 +219,14 @@ bool maxim_max30102_reset()
         return true;    
 }
 
+bool maxim_max30102_read_temperature(int8_t *integer_part, uint8_t *fractional_part)
+{
+  maxim_max30102_write_reg(REG_TEMP_CONFIG,0x1); // Enabling TEMP_EN
+  delayMicroseconds(1); // Let the processor do its work
+  // For proper conversion, read the integer part as uint8_t
+  uint8_t temp;
+  maxim_max30102_read_reg(REG_TEMP_INTR, &temp); // 2's complement integer part of the temperature in degrees Celsius
+  *integer_part = temp;
+  maxim_max30102_read_reg(REG_TEMP_FRAC, fractional_part); // Fractional part of the temperature in 1/16-th degree Celsius
+  return true;
+}

max30102.h

@@ -104,4 +104,5 @@ bool maxim_max30102_read_fifo(uint32_t *pun_red_led, uint32_t *pun_ir_led);
 bool maxim_max30102_write_reg(uint8_t uch_addr, uint8_t uch_data);
 bool maxim_max30102_read_reg(uint8_t uch_addr, uint8_t *puch_data);
 bool maxim_max30102_reset(void);
+bool maxim_max30102_read_temperature(int8_t *integer_part, uint8_t *fractional_part);
 #endif /*  MAX30102_H_ */