10 DOF IMU Sensor. Reading Wrong Data

Other Hardware Sensors
1

I have bougth this sensor 10 DOF IMU Sensor Waveshare ( http://www.waveshare.com/10-dof-imu-sensor-b.htm ). I have write a code which read the X value from Gyro but the values have no make sense.This is my code

#include <SPI.h>
#include "Wire.h"

#define MPU9250_ADDRESS 0x68
#define AK8963_ADDRESS  0x0C
#define BMP180_ADRESS   0X77
#define PWR_MGMT_1      0x6B
#define SMPLRT_DIV      0x19
#define CONFIG          0x1A
#define GYRO_CONFIG     0x1B
#define GYRO_XOUT_H     0x43
#define GYRO_XOUT_L     0x44

void setup()
{
  Wire.begin();
  TWBR = 24;            // Two Wire Bit Rate Register(Controls the frequency of the clock (SCL)Hz)
  Serial.begin(115200);
  initMPU9250();
}

void loop ()
{
  // Read gyroscope
  uint8_t Buf[2];
  I2Cread(MPU9250_ADDRESS, GYRO_XOUT_H, 2, Buf);
 
  // Create 16 bits values from 8 bits data
  // Gyroscope
  int16_t gx = -(Buf[0]  << 8 | Buf[1]);
 
  // Display values Gyroscope
  Serial.print (gx, DEC); 
  Serial.print ("\t");
  delay(1000);
}

// Write a byte (Data) in device (Address) at register (Register)
void I2CwriteByte(uint8_t Address, uint8_t Register, uint8_t Data)
{
  // Set register address
  Wire.beginTransmission(Address);
  Wire.write(Register);
  Wire.write(Data);
  Wire.endTransmission();
}


// This function read Nbytes bytes from I2C device at address Address. 
// Put read bytes starting at register Register in the Data array. 
void I2Cread(uint8_t Address, uint8_t Register, uint8_t Nbytes, uint8_t* Data)
{
  // Set register address
  Wire.beginTransmission(Address);
  Wire.write(Register);
  Wire.endTransmission();
 
  // Read Nbytes
  Wire.requestFrom(Address, Nbytes); 
  uint8_t index = 0;
  while (Wire.available())
    Data[index++] = Wire.read();
}

void initMPU9250()
{
/**
* Just wakes the device up, because it sets the 
* sleep bit to 0. Also sets
* the clock source to internal.
*/  
  I2CwriteByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x00);
  delay(100);
/**
* Setting the digital low pass filter to
* Acc Bandwidth (Hz) = 184
* Acc Delay (ms) = 2.0
* Gyro Bandwidth (Hz) = 188
* Gyro Delay (ms) = 1.9
* Fs (kHz) = 1
*
*/   
  I2CwriteByte(MPU9250_ADDRESS, PWR_MGMT_1, 0x01);
  delay(200);
/**
* Setting the digital low pass filter to
* Acc Bandwidth (Hz) = 184
* Acc Delay (ms) = 2.0
* Gyro Bandwidth (Hz) = 188
* Gyro Delay (ms) = 1.9
* Fs (kHz) = 1
*
*/  
  I2CwriteByte(MPU9250_ADDRESS, CONFIG, 0x03);
/**
* Sets the smaple rate divider for the gyroscopes and 
* accelerometers. This
* means
* acc-rate = 1kHz / 1+ sample-rate
* and
* gyro-rate = 8kHz /1+ sample-rate.
* The concrete value 0 leaves the sample rate on
* default, which means 1kHz for acc-rate and 
* 8kHz for gyr-rate.
*/
  I2CwriteByte(MPU9250_ADDRESS, SMPLRT_DIV, 0x00);  
  delay(100);

  I2CwriteByte(MPU9250_ADDRESS, GYRO_CONFIG,0xE1);
}

The Output is
-18686 -18374 -18500 -18872 -18474 -18722 -18562 -18486 -18658 -18822 -18310 -18598 -18524 -18574

And when I move my sensor nothing change.

What is Wrong?

2

  int16_t gx = -(Buf[0]  << 8 | Buf[1]);Why the negative sign?

3

I dont know..:slight_smile: but the results it's the same without sign

4

Hi death_soldier,

It might be worth taking a look at Kris Winer's excellent code for the MPU-9250. It uses I2C. Here's the link: GitHub - kriswiner/MPU9250: Arduino sketches for MPU9250 9DoF with AHRS sensor fusion

5

OK.Thanks I'll try it

6

I try Kris Winer's but Can't upload it says 'I2C_MASTER' was not declared in this scope.

I try that library (GitHub - Snowda/MPU9250: MPU9250 Accelerometer Driver for Arduino) I correct the registers .The ouput gives me Zero's

Have exist anoher library?