2

I am trying to use an MPU6050 with my SAMD21-based board (a LightAPRS W-2), but it doesn't work.

The sensor definitely works, as I can get data from another 3.3 Vlogic-level board, and the sensor works with a level shifter with an Arduino Uno.

I do not know what is wrong. My SAMD21 board I2C works fine with other devices, but both the MPU6050 and the MPU9250 don't work. Here is the code I use:

/***************************************************************************
* Example sketch for the MPU9250_WE library
*
* This sketch shows how to measure pitch and roll angles from the MPU9250. 
* I have also included the corrected angle method for comparison.  
* 
* For further information visit my blog:
*
* https://wolles-elektronikkiste.de/mpu9250-9-achsen-sensormodul-teil-1  (German)
* https://wolles-elektronikkiste.de/en/mpu9250-9-axis-sensor-module-part-1  (English)
* 
***************************************************************************/

#include <MPU9250_WE.h>
#include <Wire.h>
#define MPU9250_ADDR 0x68

/* There are several ways to create your MPU9250 object:
 * MPU9250_WE myMPU9250 = MPU9250_WE()              -> uses Wire / I2C Address = 0x68
 * MPU9250_WE myMPU9250 = MPU9250_WE(MPU9250_ADDR)  -> uses Wire / MPU9250_ADDR
 * MPU9250_WE myMPU9250 = MPU9250_WE(&wire2)        -> uses the TwoWire object wire2 / MPU9250_ADDR
 * MPU9250_WE myMPU9250 = MPU9250_WE(&wire2, MPU9250_ADDR) -> all together
 * Successfully tested with two I2C busses on an ESP32
 */
MPU9250_WE myMPU9250 = MPU9250_WE(MPU9250_ADDR);

void setup() {
  Serial.begin(115200);
  Wire.begin();
  if (!myMPU9250.init()) {
    Serial.println("MPU9250 does not respond");
  } else {
    Serial.println("MPU9250 is connected");
  }
 
  /* The slope of the curve of acceleration vs measured values fits quite well to the theoretical 
   * values, e.g. 16384 units/g in the +/- 2g range. But the starting point, if you position the 
   * MPU9250 flat, is not necessarily 0g/0g/1g for x/y/z. The autoOffset function measures offset 
   * values. It assumes your MPU9250 is positioned flat with its x,y-plane. The more you deviate 
   * from this, the less accurate will be your results.
   * The function also measures the offset of the gyroscope data. The gyroscope offset does not   
   * depend on the positioning.
   * This function needs to be called at the beginning since it can overwrite your settings!
   */
  Serial.println("Position you MPU9250 flat and don't move it - calibrating...");
  delay(1000);
  myMPU9250.autoOffsets();
  Serial.println("Done!");
  
  /*  This is a more accurate method for calibration. You have to determine the minimum and maximum 
   *  raw acceleration values of the axes determined in the range +/- 2 g. 
   *  You call the function as follows: setAccOffsets(xMin,xMax,yMin,yMax,zMin,zMax);
   *  Use either autoOffset or setAccOffsets, not both.
   */
  //myMPU9250.setAccOffsets(-14240.0, 18220.0, -17280.0, 15590.0, -20930.0, 12080.0);
  
  /*  Sample rate divider divides the output rate of the gyroscope and accelerometer.
   *  Sample rate = Internal sample rate / (1 + divider) 
   *  It can only be applied if the corresponding DLPF is enabled and 0<DLPF<7!
   *  Divider is a number 0...255
   */
  myMPU9250.setSampleRateDivider(5);

  /*  MPU9250_ACC_RANGE_2G      2 g    (default)
   *  MPU9250_ACC_RANGE_4G      4 g
   *  MPU9250_ACC_RANGE_8G      8 g   
   *  MPU9250_ACC_RANGE_16G    16 g
   */
  myMPU9250.setAccRange(MPU9250_ACC_RANGE_2G);

  /*  Enable/disable the digital low pass filter for the accelerometer 
   *  If disabled the bandwidth is 1.13 kHz, delay is 0.75 ms, output rate is 4 kHz
   */
  myMPU9250.enableAccDLPF(true);


  /*  Digital low pass filter (DLPF) for the accelerometer, if enabled 
   *  MPU9250_DPLF_0, MPU9250_DPLF_2, ...... MPU9250_DPLF_7 
   *   DLPF     Bandwidth [Hz]      Delay [ms]    Output rate [kHz]
   *     0           460               1.94           1
   *     1           184               5.80           1
   *     2            92               7.80           1
   *     3            41              11.80           1
   *     4            20              19.80           1
   *     5            10              35.70           1
   *     6             5              66.96           1
   *     7           460               1.94           1
   */
  myMPU9250.setAccDLPF(MPU9250_DLPF_6);  
}

void loop() {
  xyzFloat angles = myMPU9250.getAngles();
  
/* This method provides quite precise values for x/y 
   angles up 60°. */
  Serial.print("Angle x = ");
  Serial.print(angles.x);
  Serial.print("  |  Angle y = ");
  Serial.print(angles.y);
  Serial.print("  |  Angle z = ");
  Serial.println(angles.z);

/* Pitch and roll consider all axes for calculation. According to my experience
   it provides more reliable results at higher angles (>60°) */
  float pitch = myMPU9250.getPitch();
  float roll  = myMPU9250.getRoll();
  
  Serial.print("Pitch   = "); 
  Serial.print(pitch); 
  Serial.print("  |  Roll    = "); 
  Serial.println(roll); 
  Serial.println();
  
  delay(1000);
}
2
  • are you saying that nothing prints in the serial monitor?
    – jsotola
    Apr 28, 2023 at 0:42
  • @jsotola The serial monitor works fine, and it prints "MPU9250 does not respond" Apr 28, 2023 at 10:18

0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.