Arduino en español
Circuitos con Arduino - Juan Antonio Villalpando
-- Tutorial de iniciación a Arduino --
Volver al índice del tutorial
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47.- Medidor de campo magnético y Brújula.
HMC5883L. Bus I2C.
Mide el campo magnético en los ejes X, Y, Z. Se puede utilizar como Brújula.
Las medidas obtenidas son microTeslas (uT).
Comunicación: Bus I2C
Dirección I2C: 0x1E
- [Consulta el tutorial: 31.- Pantalla LCD. Bus I2C, hay una aplicación para escanear y comprobar la dirección I2C, consulta si la tuya es 0x1E]
Hoja de datos: HMC5883L-FDS.pdf
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1.- Conexión.
______________________________
2.- Código. Medidas de campo magnético.
Código |
/*
An Arduino code example for interfacing with the HMC5883
by: Jordan McConnell
SparkFun Electronics
created on: 6/30/11
license: OSHW 1.0, http://freedomdefined.org/OSHW
Analog input 4 I2C SDA
Analog input 5 I2C SCL
*/
#include <Wire.h> //I2C Arduino Library
#define address 0x1E //0011110b, I2C 7bit address of HMC5883
void setup(){
//Initialize Serial and I2C communications
Serial.begin(9600);
Wire.begin();
//Put the HMC5883 IC into the correct operating mode
Wire.beginTransmission(address); //open communication with HMC5883
Wire.write(0x02); //select mode register
Wire.write(0x00); //continuous measurement mode
Wire.endTransmission();
}
void loop(){
int x,y,z; //triple axis data
//Tell the HMC5883 where to begin reading data
Wire.beginTransmission(address);
Wire.write(0x03); //select register 3, X MSB register
Wire.endTransmission();
//Read data from each axis, 2 registers per axis
Wire.requestFrom(address, 6);
if(6<=Wire.available()){
x = Wire.read()<<8; //X msb
x |= Wire.read(); //X lsb
z = Wire.read()<<8; //Z msb
z |= Wire.read(); //Z lsb
y = Wire.read()<<8; //Y msb
y |= Wire.read(); //Y lsb
}
//Print out values of each axis
Serial.print("x: ");
Serial.print(x);
Serial.print(" y: ");
Serial.print(y);
Serial.print(" z: ");
Serial.println(z);
delay(250);
}
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- El código anterior obtiene el campo magnético en tres direcciones, para obtener la orientación debemos utilizar varias fórmulas, están en en siguiente código
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3.- Código con la librería de Adafruit. Brújula.
Baja este archivo: Adafruit_HMC5883_Unified_Y_Sensor.zip lo descomprimes, obtendrás dos carpetas.
Adafruit_HC5833_Unified y Adafruit_Sensor.
Copia las dos en la carpeta libaries del IDE de Arduino.
Obtenido de :
https://github.com/adafruit/Adafruit_HMC5883_Unified
https://github.com/adafruit/Adafruit_Sensor
Heading (degrees) marca al norte.
La orientación la calcula en esta línea:
float heading = atan2(event.magnetic.y, event.magnetic.x);
Página para obtener la declinación:
http://www.magnetic-declination.com/
Pasamos el valor Magnetic Declination, de grados a radianes y ponemos el valor obtenido en...
float declinationAngle = aqui;
Código |
/***************************************************************************
This is a library example for the HMC5883 magnentometer/compass
Designed specifically to work with the Adafruit HMC5883 Breakout
http://www.adafruit.com/products/1746
*** You will also need to install the Adafruit_Sensor library! ***
These displays use I2C to communicate, 2 pins are required to interface.
Adafruit invests time and resources providing this open source code,
please support Adafruit andopen-source hardware by purchasing products
from Adafruit!
Written by Kevin Townsend for Adafruit Industries with some heading example from
Love Electronics (loveelectronics.co.uk)
This program is free software: you can redistribute it and/or modify
it under the terms of the version 3 GNU General Public License as
published by the Free Software Foundation.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
***************************************************************************/
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_HMC5883_U.h>
/* Assign a unique ID to this sensor at the same time */
Adafruit_HMC5883_Unified mag = Adafruit_HMC5883_Unified(12345);
void displaySensorDetails(void)
{
sensor_t sensor;
mag.getSensor(&sensor);
Serial.println("------------------------------------");
Serial.print ("Sensor: "); Serial.println(sensor.name);
Serial.print ("Driver Ver: "); Serial.println(sensor.version);
Serial.print ("Unique ID: "); Serial.println(sensor.sensor_id);
Serial.print ("Max Value: "); Serial.print(sensor.max_value); Serial.println(" uT");
Serial.print ("Min Value: "); Serial.print(sensor.min_value); Serial.println(" uT");
Serial.print ("Resolution: "); Serial.print(sensor.resolution); Serial.println(" uT");
Serial.println("------------------------------------");
Serial.println("");
delay(500);
}
void setup(void)
{
Serial.begin(9600);
Serial.println("HMC5883 Magnetometer Test"); Serial.println("");
/* Initialise the sensor */
if(!mag.begin())
{
/* There was a problem detecting the HMC5883 ... check your connections */
Serial.println("Ooops, no HMC5883 detected ... Check your wiring!");
while(1);
}
/* Display some basic information on this sensor */
displaySensorDetails();
}
void loop(void)
{
/* Get a new sensor event */
sensors_event_t event;
mag.getEvent(&event);
/* Display the results (magnetic vector values are in micro-Tesla (uT)) */
Serial.print("X: "); Serial.print(event.magnetic.x); Serial.print(" ");
Serial.print("Y: "); Serial.print(event.magnetic.y); Serial.print(" ");
Serial.print("Z: "); Serial.print(event.magnetic.z); Serial.print(" ");Serial.println("uT");
// Hold the module so that Z is pointing 'up' and you can measure the heading with x&y
// Calculate heading when the magnetometer is level, then correct for signs of axis.
float heading = atan2(event.magnetic.y, event.magnetic.x);
// Once you have your heading, you must then add your 'Declination Angle',
// which is the 'Error' of the magnetic field in your location.
// Find yours here: http://www.magnetic-declination.com/
// Mine is: -13* 2' W, which is ~13 Degrees, or (which we need) 0.22 radians
// If you cannot find your Declination, comment out these two lines, your compass will be slightly off.
float declinationAngle = 0.22;
heading += declinationAngle;
// Correct for when signs are reversed.
if(heading < 0)
heading += 2*PI;
// Check for wrap due to addition of declination.
if(heading > 2*PI)
heading -= 2*PI;
// Convert radians to degrees for readability.
float headingDegrees = heading * 180/M_PI;
Serial.print("Heading (degrees): "); Serial.println(headingDegrees);
delay(500);
} |
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- Propuestas.
- Observa si las medidas X, Y, Z de los dos códigos anteriores son iguales.
- En el primer código inserta las fórmulas necesarias para obtener la orientación. Toma esas fórmulas del segundo código.
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
Otros códigos
https://github.com/manifestinteractive/arduino/tree/master/Libraries/HMC5883L
https://github.com/jarzebski/Arduino-HMC5883L
HMC5883L.rar
Código |
/*
HMC5883L_Example.pde - Example sketch for integration with an HMC5883L triple axis magnetomerwe.
Copyright (C) 2011 Love Electronics (loveelectronics.co.uk)
This program is free software: you can redistribute it and/or modify
it under the terms of the version 3 GNU General Public License as
published by the Free Software Foundation.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/***************************************************
?????: HMC5883L_Example
??: HMC5883L??????????????????
??: 2013?3?1?
Modified and added Japanese comments
???? ???
URL: http://www.androciti.com
Wiki:http://wiki.androciti.com
Email: info@androciti.com
****************************************************/
// Reference the I2C Library
#include <Wire.h>
// Reference the HMC5883L Compass Library
#include <HMC5883L.h>
// Store our compass as a variable.
HMC5883L compass;
// Record any errors that may occur in the compass.
int error = 0;
// Out setup routine, here we will configure the microcontroller and compass.
void setup()
{
// Initialize the serial port.
Serial.begin(9600);
Serial.println("Starting the I2C interface.");
Wire.begin(); // Start the I2C interface.
Serial.println("Constructing new HMC5883L");
compass = HMC5883L(); // Construct a new HMC5883 compass.
Serial.println("Setting scale to +/- 1.3 Ga");
error = compass.SetScale(1.3); // Set the scale of the compass. ???????
if(error != 0) // If there is an error, print it out.
Serial.println(compass.GetErrorText(error));
Serial.println("Setting measurement mode to continous.");
error = compass.SetMeasurementMode(Measurement_Continuous); // Set the measurement mode to Continuous
if(error != 0) // If there is an error, print it out.
Serial.println(compass.GetErrorText(error));
}
// Our main program loop.
void loop()
{
// Retrive the raw values from the compass (not scaled).
MagnetometerRaw raw = compass.ReadRawAxis();
// Retrived the scaled values from the compass (scaled to the configured scale).
MagnetometerScaled scaled = compass.ReadScaledAxis();
// Values are accessed like so:
int MilliGauss_OnThe_XAxis = scaled.XAxis;// (or YAxis, or ZAxis)
// Calculate heading when the magnetometer is level, then correct for signs of axis.
float heading = atan2(scaled.YAxis, scaled.XAxis);
// Once you have your heading, you must then add your 'Declination Angle', which is the 'Error' of the magnetic field in your location.
// Find yours here: http://www.magnetic-declination.com/
// Mine is: 2� 37' W, which is 2.617 Degrees, or (which we need) 0.0456752665 radians, I will use 0.0457
// If you cannot find your Declination, comment out these two lines, your compass will be slightly off.
// float declinationAngle = 0.0457;
// ?????????????? ?7°18 '(??) =127.4 mrad
// ????????? http://magnetic-declination.com/?http://vldb.gsi.go.jp/sokuchi/geomag/menu_01/index.html??????????
float declinationAngle = 0.1274;
// ?????????? -= declinationAngle?????? += declinationAngle?????????
heading += declinationAngle;
// Correct for when signs are reversed.
if(heading < 0)
heading += 2*PI;
// Check for wrap due to addition of declination.
if(heading > 2*PI)
heading -= 2*PI;
// Convert radians to degrees for readability.
float headingDegrees = heading * 180/M_PI;
// Output the data via the serial port.
Output(raw, scaled, heading, headingDegrees);
// Normally we would delay the application by 66ms to allow the loop
// to run at 15Hz (default bandwidth for the HMC5883L).
// However since we have a long serial out (104ms at 9600) we will let
// it run at its natural speed.
// delay(66);
}
// Output the data down the serial port.
void Output(MagnetometerRaw raw, MagnetometerScaled scaled, float heading, float headingDegrees)
{
Serial.print("Raw:\t"); //????
Serial.print(raw.XAxis);
Serial.print(" ");
Serial.print(raw.YAxis);
Serial.print(" ");
Serial.print(raw.ZAxis);
Serial.print(" \tScaled:\t");
Serial.print(scaled.XAxis); // ?????????????????????
Serial.print(" ");
Serial.print(scaled.YAxis);
Serial.print(" ");
Serial.print(scaled.ZAxis);
Serial.print(" \tHeading:\t"); // ???????????????
Serial.print(heading);
Serial.print(" Radians \t");
Serial.print(headingDegrees);
Serial.println(" Degrees \t");
}
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- https://www.sparkfun.com/tutorials/301
Librería Adafruit brújula
Librería de muchos sensores Adafruit
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