Code for multiple I2C sensors

Projects Programming
1

I'm using Bluerobotics Bar30 pressure sensor (I2C) and MPU9250 IMU sensor (also I2C) with Arduino UNO.

The following code is working perfectly:

#include "MPU9250.h"
MPU9250 mpu9250;

#include <Wire.h>
#include "MS5837.h"
MS5837 sensor;

void setup() {
    Serial.begin(9600);
    Wire.begin();
    delay(2000);

    if (!mpu9250.setup(0x68)) {  // change to your own address
        while (1) {
            Serial.println("MPU connection failed. Please check your connection with `connection_check` example.");
            delay(5000);
        }
    }
  while (!sensor.init()) {
    Serial.println("Init failed!");
    Serial.println("Are SDA/SCL connected correctly?");
    Serial.println("Blue Robotics Bar30: White=SDA, Green=SCL");
    Serial.println("\n\n\n");
    delay(5000);
  }
  
  sensor.setModel(MS5837::MS5837_30BA);
  sensor.setFluidDensity(997);
  
  }

void loop() {
    if (mpu9250.update()) {
        static uint32_t prev_ms = millis();
        if (millis() > prev_ms + 25) {
            print_roll_pitch_yaw();
            prev_ms = millis();
        }
    }
  sensor.read();
  Serial.print(sensor.pressure()); 
  Serial.println(" mbar");
  }

void print_roll_pitch_yaw() {
    Serial.print("Yaw, Pitch, Roll: ");
    Serial.print(mpu9250.getYaw(), 2);
    Serial.print(", ");
    Serial.print(mpu9250.getPitch(), 2);
    Serial.print(", ");
    Serial.println(mpu9250.getRoll(), 2);

 }

However, the following code isn't working. I'm getting the pressure values from the Bar30 sensor, but mpu9250 values aren't coming on the serial monitor, it's all zeros.

#include "MPU9250.h"

#include <Wire.h> //
#include "MS5837.h" //
MS5837 sensor; //

MPU9250 mpu;

void setup() {
  digitalWrite(13, LOW);
    Serial.begin(115200);
    Wire.begin();

    if (!mpu.setup(0x68)) {  // change to your own address
        while (1) {
            Serial.println("MPU connection failed. Please check your connection with `connection_check` example.");
            delay(5000);
        }
    }
    
   while (!sensor.init()) 
   { //
    Serial.println("Init failed!");
    Serial.println("Are SDA/SCL connected correctly?");
    Serial.println("Blue Robotics Bar30: White=SDA, Green=SCL");
    Serial.println("\n\n\n");
    delay(5000);
  }
  sensor.setModel(MS5837::MS5837_30BA);
  sensor.setFluidDensity(997); // kg/m^3 (freshwater, 1029 for seawater)
}

void loop() {
    if (mpu.update()) {
        static uint32_t prev_ms = millis();
        if (millis() > prev_ms + 25) {
            print_roll_pitch_yaw();
            prev_ms = millis();
        }
    }
}

void print_roll_pitch_yaw() {
    Serial.print(mpu.getYaw(), 2);
    Serial.print(", ");
    Serial.print(mpu.getPitch(), 2);
    Serial.print(", ");
    Serial.print(mpu.getRoll(), 2);
    Serial.print(", ");

      sensor.read();
  Serial.print(sensor.pressure()); 
  Serial.print(", ");
  Serial.print(sensor.temperature()); 
  Serial.print(", ");
  Serial.print(sensor.depth()); 
  Serial.print(", ");
  Serial.println(sensor.altitude());

  delay(100);

}

Can't understand why. The only difference is that this part:

sensor.read(); Serial.print(sensor.pressure()); Serial.println(" mbar");

is in the print_roll_pitch_yaw function in the code that's working, while in the second code which isn't working, this part of the code is in the loop function.

2

If it was the other way around I had said that it's the I2C speed (MP9250 library set it to 400kHz but the MS5837's datasheet says ti also supports that speed.

Unfortunately you didn't provide links to the used libraries so I had to guess. I didn't find your MPU9250 library, all libraries of that name available in the Library Manager don't offer an update() method. I guess it's some kind of race condition but without the code that's impossible to find.

3

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