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- // Arduino sketch that returns calibration offsets for MPU6050 // Version 1.1 (31th January 2014)
- // Done by Luis Ródenas <luisrodenaslorda@gmail.com>
- // Based on the I2Cdev library and previous work by Jeff Rowberg <jeff@rowberg.net>
- // Updates (of the library) should (hopefully) always be available at https://github.com/jrowberg/i2cdevlib
- // These offsets were meant to calibrate MPU6050's internal DMP, but can be also useful for reading sensors.
- // The effect of temperature has not been taken into account so I can't promise that it will work if you
- // calibrate indoors and then use it outdoors. Best is to calibrate and use at the same room temperature.
- /* ========== LICENSE ==================================
- I2Cdev device library code is placed under the MIT license
- Copyright (c) 2011 Jeff Rowberg
- Permission is hereby granted, free of charge, to any person obtaining a copy
- of this software and associated documentation files (the "Software"), to deal
- in the Software without restriction, including without limitation the rights
- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- copies of the Software, and to permit persons to whom the Software is
- furnished to do so, subject to the following conditions:
- The above copyright notice and this permission notice shall be included in
- all copies or substantial portions of the Software.
- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- THE SOFTWARE.
- =========================================================
- */
- // I2Cdev and MPU6050 must be installed as libraries
- #include "I2Cdev.h"
- #include "MPU6050.h"
- #include "Wire.h"
- /////////////////////////////////// CONFIGURATION /////////////////////////////
- //Change this 3 variables if you want to fine tune the skecth to your needs.
- int buffersize=1000; //Amount of readings used to average, make it higher to get more precision but sketch will be slower (default:1000)
- int acel_deadzone=8; //Acelerometer error allowed, make it lower to get more precision, but sketch may not converge (default:8)
- int giro_deadzone=1; //Giro error allowed, make it lower to get more precision, but sketch may not converge (default:1)
- // default I2C address is 0x68
- // specific I2C addresses may be passed as a parameter here
- // AD0 low = 0x68 (default for InvenSense evaluation board)
- // AD0 high = 0x69
- //MPU6050 accelgyro;
- MPU6050 accelgyro(0x68); // <-- use for AD0 high
- int16_t ax, ay, az,gx, gy, gz;
- int mean_ax,mean_ay,mean_az,mean_gx,mean_gy,mean_gz,state=0;
- int ax_offset,ay_offset,az_offset,gx_offset,gy_offset,gz_offset;
- /////////////////////////////////// SETUP ////////////////////////////////////
- void setup() {
- // join I2C bus (I2Cdev library doesn't do this automatically)
- Wire.begin();
- // COMMENT NEXT LINE IF YOU ARE USING ARDUINO DUE
- TWBR = 24; // 400kHz I2C clock (200kHz if CPU is 8MHz). Leonardo measured 250kHz.
- // initialize serial communication
- Serial.begin(115200);
- // initialize device
- accelgyro.initialize();
- // wait for ready
- while (Serial.available() && Serial.read()); // empty buffer
- while (!Serial.available()){
- Serial.println(F("Send any character to start sketch.\n"));
- delay(1500);
- }
- while (Serial.available() && Serial.read()); // empty buffer again
- // start message
- Serial.println("\nMPU6050 Calibration Sketch");
- delay(2000);
- Serial.println("\nYour MPU6050 should be placed in horizontal position, with package letters facing up. \nDon't touch it until you see a finish message.\n");
- delay(3000);
- // verify connection
- Serial.println(accelgyro.testConnection() ? "MPU6050 connection successful" : "MPU6050 connection failed");
- delay(1000);
- // reset offsets
- accelgyro.setXAccelOffset(0);
- accelgyro.setYAccelOffset(0);
- accelgyro.setZAccelOffset(0);
- accelgyro.setXGyroOffset(0);
- accelgyro.setYGyroOffset(0);
- accelgyro.setZGyroOffset(0);
- }
- /////////////////////////////////// LOOP ////////////////////////////////////
- void loop() {
- if (state==0){
- Serial.println("\nReading sensors for first time...");
- meansensors();
- state++;
- delay(1000);
- }
- if (state==1) {
- Serial.println("\nCalculating offsets...");
- calibration();
- state++;
- delay(1000);
- }
- if (state==2) {
- meansensors();
- Serial.println("\nFINISHED!");
- Serial.print("\nSensor readings with offsets:\t");
- Serial.print(mean_ax);
- Serial.print("\t");
- Serial.print(mean_ay);
- Serial.print("\t");
- Serial.print(mean_az);
- Serial.print("\t");
- Serial.print(mean_gx);
- Serial.print("\t");
- Serial.print(mean_gy);
- Serial.print("\t");
- Serial.println(mean_gz);
- Serial.print("Your offsets:\t");
- Serial.print(ax_offset);
- Serial.print("\t");
- Serial.print(ay_offset);
- Serial.print("\t");
- Serial.print(az_offset);
- Serial.print("\t");
- Serial.print(gx_offset);
- Serial.print("\t");
- Serial.print(gy_offset);
- Serial.print("\t");
- Serial.println(gz_offset);
- Serial.println("\nData is printed as: acelX acelY acelZ giroX giroY giroZ");
- Serial.println("Check that your sensor readings are close to 0 0 16384 0 0 0");
- Serial.println("If calibration was succesful write down your offsets so you can set them in your projects using something similar to mpu.setXAccelOffset(youroffset)");
- while (1);
- }
- }
- /////////////////////////////////// FUNCTIONS ////////////////////////////////////
- void meansensors(){
- long i=0,buff_ax=0,buff_ay=0,buff_az=0,buff_gx=0,buff_gy=0,buff_gz=0;
- while (i<(buffersize+101)){
- // read raw accel/gyro measurements from device
- accelgyro.getMotion6(&ax, &ay, &az, &gx, &gy, &gz);
- if (i>100 && i<=(buffersize+100)){ //First 100 measures are discarded
- buff_ax=buff_ax+ax;
- buff_ay=buff_ay+ay;
- buff_az=buff_az+az;
- buff_gx=buff_gx+gx;
- buff_gy=buff_gy+gy;
- buff_gz=buff_gz+gz;
- }
- if (i==(buffersize+100)){
- mean_ax=buff_ax/buffersize;
- mean_ay=buff_ay/buffersize;
- mean_az=buff_az/buffersize;
- mean_gx=buff_gx/buffersize;
- mean_gy=buff_gy/buffersize;
- mean_gz=buff_gz/buffersize;
- }
- i++;
- delay(2); //Needed so we don't get repeated measures
- }
- }
- void calibration(){
- ax_offset=-mean_ax/8;
- ay_offset=-mean_ay/8;
- az_offset=(16384-mean_az)/8;
- gx_offset=-mean_gx/4;
- gy_offset=-mean_gy/4;
- gz_offset=-mean_gz/4;
- while (1){
- int ready=0;
- accelgyro.setXAccelOffset(ax_offset);
- accelgyro.setYAccelOffset(ay_offset);
- accelgyro.setZAccelOffset(az_offset);
- accelgyro.setXGyroOffset(gx_offset);
- accelgyro.setYGyroOffset(gy_offset);
- accelgyro.setZGyroOffset(gz_offset);
- meansensors();
- Serial.println("...");
- if (abs(mean_ax)<=acel_deadzone) ready++;
- else ax_offset=ax_offset-mean_ax/acel_deadzone;
- if (abs(mean_ay)<=acel_deadzone) ready++;
- else ay_offset=ay_offset-mean_ay/acel_deadzone;
- if (abs(16384-mean_az)<=acel_deadzone) ready++;
- else az_offset=az_offset+(16384-mean_az)/acel_deadzone;
- if (abs(mean_gx)<=giro_deadzone) ready++;
- else gx_offset=gx_offset-mean_gx/(giro_deadzone+1);
- if (abs(mean_gy)<=giro_deadzone) ready++;
- else gy_offset=gy_offset-mean_gy/(giro_deadzone+1);
- if (abs(mean_gz)<=giro_deadzone) ready++;
- else gz_offset=gz_offset-mean_gz/(giro_deadzone+1);
- if (ready==6) break;
- }
- }
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