GiovanniCmpaner
commented
3 years ago You have to call calibrateAccel() in a loop and move the hardware physically before each call.
Think of the hardware as a plain cube with 6 faces, each position would be one face to the touching the ground / table.
Here is an example:
#include <Arduino.h>
#include <Wire.h>
#include <MPU9250.h>
MPU9250 mpu(Wire, 0x68);
void setup()
{
Serial.begin(115200);
Serial.println("Doing calibration");
mpu.begin();
for(int n = 0; n < 6; n++)
{
Serial.print("Move the car into position ");
Serial.print(n);
Serial.println();
delay(7000);
mpu.calibrateAccel();
}
Serial.println("Calibration done");
Serial.print("bias x = ");
Serial.print(mpu.getAccelBiasX_mss(), 5);
Serial.println();
Serial.print("bias y = ");
Serial.print(mpu.getAccelBiasY_mss(), 5);
Serial.println();
Serial.print("bias z = ");
Serial.print(mpu.getAccelBiasZ_mss(), 5);
Serial.println();
Serial.print("factor x = ");
Serial.print(mpu.getAccelScaleFactorX(), 5);
Serial.println();
Serial.print("factor y = ");
Serial.print(mpu.getAccelScaleFactorY(), 5);
Serial.println();
Serial.print("factor z = ");
Serial.print(mpu.getAccelScaleFactorZ(), 5);
Serial.println();
}
void loop()
{
}Then you use those numbers in the real code:
#include <Arduino.h>
#include <Wire.h>
#include <MPU9250.h>
MPU9250 mpu(Wire, 0x68);
const float accelBias[3] = { 0.11111, 0.22222, 0.33333 }; // Obtained through calibration scketch
const float accelFactor[3] = { 0.11111, 0.22222, 0.33333 }; // Obtained through calibration scketch
void setup()
{
Serial.begin(115200);
Serial.println("Doing calibrated reading");
mpu.begin();
mpu.setAccelCalX(accelBias[0], accelFactor[0]);
mpu.setAccelCalY(accelBias[1], accelFactor[1]);
mpu.setAccelCalZ(accelBias[2], accelFactor[2]);
}
void loop()
{
mpu.readSensor();
Serial.print("accel x = ");
Serial.print(mpu.getAccelX_mss(), 5);
Serial.println();
Serial.print("accel y = ");
Serial.print(mpu.getAccelY_mss(), 5);
Serial.println();
Serial.print("accel z = ");
Serial.print(mpu.getAccelZ_mss(), 5);
Serial.println();
Serial.println();
delay(100);
}
paulrossmanith
flybrianfly
Hey! I am experiencing difficulty calibrating my sensor. The accelerometer values are biased and gyroscope readings are too low. I have attached a part of my code below. Please reply with an example sketch on how to calibrate the sensor. I'd be really grateful for your help. Thanks in advance
include "MPU9250.h"
// an MPU9250 object with the MPU-9250 sensor on I2C bus 0 with address 0x68 MPU9250 IMU(Wire,0x68); int status; int statusAcc; int statusGyr; int statusMag;
void setup() { // serial to display data Serial.begin(115200); while(!Serial) {}
// start communication with IMU status = IMU.begin(); //calibrating IMU statusAcc= IMU.calibrateAccel(); statusGyr= IMU.calibrateGyro(); statusMag= IMU.calibrateMag();
if (status < 0) { Serial.println("IMU initialization unsuccessful"); Serial.println("Check IMU wiring or try cycling power"); Serial.print("Status: "); Serial.println(status); while(1) {} } // setting the accelerometer full scale range to +/-8G IMU.setAccelRange(MPU9250::ACCEL_RANGE_8G); // setting the gyroscope full scale range to +/-500 deg/s IMU.setGyroRange(MPU9250::GYRO_RANGE_500DPS); // setting DLPF bandwidth to 20 Hz IMU.setDlpfBandwidth(MPU9250::DLPF_BANDWIDTH_20HZ); // setting SRD to 19 for a 50 Hz update rate IMU.setSrd(19); . . . .