Revision 3:f3796683b4c9, committed 2012-05-06

Comitter:

tosihisa

Date:

Sun May 06 05:14:30 2012 +0000

Parent:

2:39cdefe3c9f2

Child:

4:3c677edffb13

Commit message:

An angle of inclination is obtained using an accelerometer.

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LSM303DLH/LSM303DLH.cpp	Sun May 06 05:14:30 2012 +0000
@@ -0,0 +1,227 @@
+/** LSM303DLH Interface Library
+ *
+ * Michael Shimniok http://bot-thoughts.com
+ *
+ * Based on test program by @tosihisa and 
+ *
+ * Pololu sample library for LSM303DLH breakout by ryantm:
+ *
+ * Copyright (c) 2011 Pololu Corporation. For more information, see
+ *
+ * http://www.pololu.com/
+ * http://forum.pololu.com/
+ *
+ * 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.
+ */
+#include "mbed.h"
+#include "LSM303DLH.h"
+
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
+#define FILTER_SHIFT 6      // used in filtering acceleromter readings
+
+const int addr_acc = 0x30;
+const int addr_mag = 0x3c;
+
+enum REG_ADDRS {
+    /* --- Mag --- */
+    CRA_REG_M   = 0x00,
+    CRB_REG_M   = 0x01,
+    MR_REG_M    = 0x02,
+    OUT_X_M     = 0x03,
+    OUT_Y_M     = 0x05,
+    OUT_Z_M     = 0x07,
+    /* --- Acc --- */
+    CTRL_REG1_A = 0x20,
+    CTRL_REG4_A = 0x23,
+    OUT_X_A     = 0x28,
+    OUT_Y_A     = 0x2A,
+    OUT_Z_A     = 0x2C,
+};
+
+bool LSM303DLH::write_reg(int addr_i2c,int addr_reg, char v)
+{
+    char data[2] = {addr_reg, v}; 
+    return LSM303DLH::_compass.write(addr_i2c, data, 2) == 0;
+}
+
+bool LSM303DLH::read_reg(int addr_i2c,int addr_reg, char *v)
+{
+    char data = addr_reg; 
+    bool result = false;
+    
+    __disable_irq();
+    if ((_compass.write(addr_i2c, &data, 1) == 0) && (_compass.read(addr_i2c, &data, 1) == 0)){
+        *v = data;
+        result = true;
+    }
+    __enable_irq();
+    return result;
+}
+
+bool LSM303DLH::read_reg_short(int addr_i2c,int addr_reg, short *v)
+{
+    char *pv = (char *)v;
+    bool result;
+    
+    result =  read_reg(addr_i2c,addr_reg+0,pv+1);
+    result &= read_reg(addr_i2c,addr_reg+1,pv+0);
+  
+    return result;
+}
+
+LSM303DLH::LSM303DLH(PinName sda, PinName scl):
+    _compass(sda, scl), _offset_x(0), _offset_y(0), _offset_z(0), _scale_x(0), _scale_y(0), _scale_z(0), _filt_ax(0), _filt_ay(0), _filt_az(6000)
+{
+    char reg_v;
+    _compass.frequency(100000);
+        
+    reg_v = 0;
+    reg_v |= 0x01 << 5;     /* Normal mode  */
+    reg_v |= 0x03 << 3;     /* Output data rate 1000 [Hz] */
+    reg_v |= 0x07;          /* X/Y/Z axis enable. */
+    write_reg(addr_acc,CTRL_REG1_A,reg_v);
+    reg_v = 0;
+    read_reg(addr_acc,CTRL_REG1_A,&reg_v);
+
+    reg_v = 0;
+    reg_v |= 0x01 << 6;     /* 1: data MSB @ lower address */
+    reg_v |= 0x01 << 4;     /* +/- 4g */
+    //reg_v |= 0x00 << 4;     /* +/- 2g */
+    write_reg(addr_acc,CTRL_REG4_A,reg_v);
+
+    /* -- mag --- */
+    reg_v = 0;
+    reg_v |= 0x04 << 2;     /* Minimum data output rate = 15Hz */
+    write_reg(addr_mag,CRA_REG_M,reg_v);
+
+    reg_v = 0;
+    //reg_v |= 0x01 << 5;     /* +-1.3Gauss */
+    reg_v |= 0x07 << 5;     /* +-8.1Gauss */
+    write_reg(addr_mag,CRB_REG_M,reg_v);
+
+    reg_v = 0;              /* Continuous-conversion mode */
+    write_reg(addr_mag,MR_REG_M,reg_v);
+}
+
+
+void LSM303DLH::setOffset(float x, float y, float z)
+{
+    _offset_x = x;
+    _offset_y = y;
+    _offset_z = z;   
+}
+
+void LSM303DLH::setScale(float x, float y, float z)
+{
+    _scale_x = x;
+    _scale_y = y;
+    _scale_z = z;
+}
+
+void LSM303DLH::read(vector &a, vector &m)
+{
+    short a_x, a_y, a_z;
+    short m_x, m_y, m_z;
+    //Timer t;
+    //int usec1, usec2;
+    
+    //t.reset();
+    //t.start();
+
+    //usec1 = t.read_us();
+    read_reg_short(addr_acc, OUT_X_A, &a_x);
+    read_reg_short(addr_acc, OUT_Y_A, &a_y);
+    read_reg_short(addr_acc, OUT_Z_A, &a_z);
+    read_reg_short(addr_mag, OUT_X_M, &m_x);
+    read_reg_short(addr_mag, OUT_Y_M, &m_y);
+    read_reg_short(addr_mag, OUT_Z_M, &m_z);
+    //usec2 = t.read_us();
+    
+    //if (debug) debug->printf("%d %d %d\n", usec1, usec2, usec2-usec1);
+
+#if 0
+    // Perform simple lowpass filtering
+    // Intended to stabilize heading despite
+    // device vibration such as on a UGV
+    _filt_ax += a_x - (_filt_ax >> FILTER_SHIFT);
+    _filt_ay += a_y - (_filt_ay >> FILTER_SHIFT);
+    _filt_az += a_z - (_filt_az >> FILTER_SHIFT);
+
+    a.x = (float) (_filt_ax >> FILTER_SHIFT);
+    a.y = (float) (_filt_ay >> FILTER_SHIFT);
+    a.z = (float) (_filt_az >> FILTER_SHIFT);
+#else
+    a.x = (float)a_x;
+    a.y = (float)a_y;
+    a.z = (float)a_z;
+#endif
+    
+    // offset and scale
+    m.x = (m_x + _offset_x) * _scale_x;
+    m.y = (m_y + _offset_y) * _scale_y;
+    m.z = (m_z + _offset_z) * _scale_z;
+}
+
+
+// Returns the number of degrees from the -Y axis that it
+// is pointing.
+float LSM303DLH::heading()
+{
+    return heading((vector){0,-1,0});
+}
+
+float LSM303DLH::heading(vector from)
+{
+    vector a, m;
+
+    this->read(a, m);
+    
+    ////////////////////////////////////////////////
+    // compute heading       
+    ////////////////////////////////////////////////
+
+    vector temp_a = a;
+    // normalize
+    vector_normalize(&temp_a);
+    //vector_normalize(&m);
+
+    // compute E and N
+    vector E;
+    vector N;
+    vector_cross(&m,&temp_a,&E);
+    vector_normalize(&E);
+    vector_cross(&temp_a,&E,&N);
+    
+    // compute heading
+    float heading = atan2(vector_dot(&E,&from), vector_dot(&N,&from)) * 180/M_PI;
+    if (heading < 0) heading += 360;
+    
+    return heading;
+}
+
+void LSM303DLH::frequency(int hz)
+{
+    _compass.frequency(hz);
+}
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LSM303DLH/LSM303DLH.h	Sun May 06 05:14:30 2012 +0000
@@ -0,0 +1,138 @@
+#include "mbed.h"
+#include "vector.h"
+
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
+/** Tilt-compensated compass interface Library for the STMicro LSM303DLH 3-axis magnetometer, 3-axis acceleromter
+ *
+ * Michael Shimniok http://bot-thoughts.com
+ *
+ * Based on test program by @tosihisa and 
+ *
+ * Pololu sample library for LSM303DLH breakout by ryantm:
+ *
+ * Copyright (c) 2011 Pololu Corporation. For more information, see
+ *
+ * http://www.pololu.com/
+ * http://forum.pololu.com/
+ *
+ * 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.
+ *
+ * @code
+ * #include "mbed.h"
+ * #include "LSM303DLH.h"
+ *
+ * Serial debug(USBTX,USBRX);
+ * LSM303DLH compass(p28, p27);
+ *
+ * int main() {
+ *   float hdg;
+ *   debug.format(8,Serial::None,1);
+ *   debug.baud(115200);
+ *   debug.printf("LSM303DLH Test\x0d\x0a");
+ *   compass.setOffset(29.50, -0.50, 4.00); // example calibration
+ *   compass.setScale(1.00, 1.03, 1.21);    // example calibration
+ *   while(1) {
+ *     hdg = compass.heading();
+ *     debug.printf("Heading: %.2f\n", hdg);
+ *     wait(0.1);
+ *   }
+ * }
+ * @endcode
+ */
+class LSM303DLH {
+    public:
+        /** Create a new interface for an LSM303DLH
+         *
+         * @param sda is the pin for the I2C SDA line
+         * @param scl is the pin for the I2C SCL line
+         */
+        LSM303DLH(PinName sda, PinName scl);
+
+        /** sets the x, y, and z offset corrections for hard iron calibration
+         * 
+         * Calibration details here:
+         *  http://mbed.org/users/shimniok/notebook/quick-and-dirty-3d-compass-calibration/
+         *
+         * If you gather raw magnetometer data and find, for example, x is offset
+         * by hard iron by -20 then pass +20 to this member function to correct
+         * for hard iron.
+         *
+         * @param x is the offset correction for the x axis
+         * @param y is the offset correction for the y axis
+         * @param z is the offset correction for the z axis
+         */
+        void setOffset(float x, float y, float z);
+        
+        /** sets the scale factor for the x, y, and z axes
+         *
+         * Calibratio details here:
+         *  http://mbed.org/users/shimniok/notebook/quick-and-dirty-3d-compass-calibration/
+         *
+         * Sensitivity of the three axes is never perfectly identical and this
+         * function can help to correct differences in sensitivity.  You're
+         * supplying a multipler such that x, y and z will be normalized to the
+         * same max/min values
+         */
+        void setScale(float x, float y, float z);
+
+        /** read the raw accelerometer and compass values
+         *
+         * @param a is the accelerometer 3d vector, written by the function
+         * @param m is the magnetometer 3d vector, written by the function
+         */
+        void read(vector &a, vector &m);
+        
+        /** returns the magnetic heading with respect to the y axis
+         *
+         */
+        float heading(void);
+        
+        /** returns the heading with respect to the specified vector
+         *
+         */
+        float heading(vector from);
+    
+        /** sets the I2C bus frequency
+         *
+         * @param frequency is the I2C bus/clock frequency, either standard (100000) or fast (400000)
+         */
+        void frequency(int hz);
+    
+    private:
+        I2C _compass;
+        float _offset_x;
+        float _offset_y;
+        float _offset_z;
+        float _scale_x;
+        float _scale_y;
+        float _scale_z;
+        long _filt_ax;
+        long _filt_ay;
+        long _filt_az;
+       
+        bool write_reg(int addr_i2c,int addr_reg, char v);
+        bool read_reg(int addr_i2c,int addr_reg, char *v);
+        bool read_reg_short(int addr_i2c,int addr_reg, short *v);
+};

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LSM303DLH/vector.cpp	Sun May 06 05:14:30 2012 +0000
@@ -0,0 +1,22 @@
+#include <vector.h>
+#include <math.h>
+
+void vector_cross(const vector *a,const vector *b, vector *out)
+{
+  out->x = a->y*b->z - a->z*b->y;
+  out->y = a->z*b->x - a->x*b->z;
+  out->z = a->x*b->y - a->y*b->x;
+}
+
+float vector_dot(const vector *a,const vector *b)
+{
+  return a->x*b->x+a->y*b->y+a->z*b->z;
+}
+
+void vector_normalize(vector *a)
+{
+  float mag = sqrt(vector_dot(a,a));
+  a->x /= mag;
+  a->y /= mag;
+  a->z /= mag;
+}
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LSM303DLH/vector.h	Sun May 06 05:14:30 2012 +0000
@@ -0,0 +1,11 @@
+#ifndef vector_h
+#define vector_h
+typedef struct vector
+{
+  float x, y, z;
+} vector;
+
+extern void vector_cross(const vector *a, const vector *b, vector *out);
+extern float vector_dot(const vector *a,const vector *b);
+extern void vector_normalize(vector *a);
+#endif
\ No newline at end of file

--- a/main.cpp	Tue Nov 30 14:42:07 2010 +0000
+++ b/main.cpp	Sun May 06 05:14:30 2012 +0000
@@ -1,122 +1,26 @@
-
-/*
- * LSM303DLH Test program
- * @tosihisa
- */
 
 #include "mbed.h"
-#ifndef M_PI
-#define M_PI 3.14159265358979323846
-#endif
-
-Serial debug(USBTX,USBRX);
-
-I2C LSM303DLH(p28, p27);
-
-const int addr_acc = 0x30;
-const int addr_mag = 0x3c;
-
-enum REG_ADDRS {
-    /* --- Mag --- */
-    CRA_REG_M   = 0x00,
-    CRB_REG_M   = 0x01,
-    MR_REG_M    = 0x02,
-    OUT_X_M     = 0x03,
-    OUT_Y_M     = 0x05,
-    OUT_Z_M     = 0x07,
-    /* --- Acc --- */
-    CTRL_REG1_A = 0x20,
-    CTRL_REG4_A = 0x23,
-    OUT_X_A     = 0x28,
-    OUT_Y_A     = 0x2A,
-    OUT_Z_A     = 0x2C,
-};
+ #include "LSM303DLH.h"
 
-bool write_reg(int addr_i2c,int addr_reg, char v)
-{
-    char data[2] = {addr_reg, v}; 
-    return LSM303DLH.write(addr_i2c, data, 2) == 0;
-}
-
-bool read_reg(int addr_i2c,int addr_reg, char *v)
-{
-    char data = addr_reg; 
-    if ((LSM303DLH.write(addr_i2c, &data, 1) == 0) && (LSM303DLH.read(addr_i2c, &data, 1) == 0)){
-        *v = data;
-        return true;
-    }
-    return false;
-}
-
-bool read_reg_short(int addr_i2c,int addr_reg, short *v)
-{
-    char *pv = (char *)v;
-    read_reg(addr_i2c,addr_reg+0,pv+1);
-    return read_reg(addr_i2c,addr_reg+1,pv+0);
-}
-
-int main() {
-    char reg_v;
-    bool result;
-    short a_x,a_y,a_z;
-    short m_x,m_y,m_z;
-    double m_deg;
+ Serial debug(USBTX,USBRX);
+ LSM303DLH compass(p28, p27);
 
-    debug.format(8,Serial::None,1);
-    debug.baud(115200);
-    debug.printf("LSM303DLH Test\x0d\x0a");
-
-    /* --- acc --- */
-    reg_v = 0;
-    result = read_reg(addr_acc,CTRL_REG1_A,&reg_v);
-    debug.printf("(%s) CTRL_REG1_A=[0x%02X]\x0d\x0a",(result) ? "OK" : "NG",reg_v);
-
-    reg_v = 0;
-    result = read_reg(addr_mag,CRA_REG_M,&reg_v);
-    debug.printf("(%s) CRA_REG_M=[0x%02X]\x0d\x0a",(result) ? "OK" : "NG",reg_v);
-
-    reg_v = 0;
-    reg_v |= 0x01 << 5;     /* Normal mode  */
-    reg_v |= 0x07;          /* X/Y/Z axis enable. */
-    result = write_reg(addr_acc,CTRL_REG1_A,reg_v);
-    reg_v = 0;
-    result = read_reg(addr_acc,CTRL_REG1_A,&reg_v);
-    debug.printf("(%s) CTRL_REG1_A=[0x%02X]\x0d\x0a",(result) ? "OK" : "NG",reg_v);
-
-    reg_v = 0;
-    reg_v |= 0x01 << 6;     /* 1: data MSB @ lower address */
-    reg_v |= 0x01 << 4;     /* +/- 4g */
-    result = write_reg(addr_acc,CTRL_REG4_A,reg_v);
-
-    /* -- mag --- */
-    reg_v = 0;
-    reg_v |= 0x04 << 2;     /* Minimum data output rate = 15Hz */
-    result = write_reg(addr_mag,CRA_REG_M,reg_v);
-
-    reg_v = 0;
-    //reg_v |= 0x01 << 5;     /* +-1.3Gauss */
-    reg_v |= 0x07 << 5;     /* +-8.1Gauss */
-    result = write_reg(addr_mag,CRB_REG_M,reg_v);
-
-    reg_v = 0;              /* Continuous-conversion mode */
-    result = write_reg(addr_mag,MR_REG_M,reg_v);
-
-    while(1) {
-        read_reg_short(addr_acc,OUT_X_A,&a_x);
-        read_reg_short(addr_acc,OUT_Y_A,&a_y);
-        read_reg_short(addr_acc,OUT_Z_A,&a_z);
-        read_reg_short(addr_mag,OUT_X_M,&m_x);
-        read_reg_short(addr_mag,OUT_Y_M,&m_y);
-        read_reg_short(addr_mag,OUT_Z_M,&m_z);
-        m_deg = (atan2((double)(m_x),(double)(m_y)) * 180) / M_PI;
-        if(m_deg < 0){
-            m_deg = m_deg * -1.0;
-        } else {
-            m_deg = 360.0 - m_deg;
-        }
-
-        debug.printf("ACC:X=%-7d,Y=%-7d,Z=%-7d ",a_x,a_y,a_z);
-        debug.printf("MAG:X=%-7d,Y=%-7d,Z=%-7d DEG=%f\x0d\x0a",m_x,m_y,m_z,m_deg);
-        wait(0.1);
-    }
-}
+ int main() {
+   float hdg;
+   float hdgV;
+   vector acc;
+   vector mag;
+   debug.format(8,Serial::None,1);
+   debug.baud(115200);
+   debug.printf("LSM303DLH Test\x0d\x0a");
+   compass.setOffset(0.00,0.00,0.00); // example calibration
+   compass.setScale(1.00,1.00,1.00);    // example calibration
+   while(1) {
+     compass.read(acc,mag);
+     hdg = compass.heading();
+     hdgV = atan2(acc.y,acc.z) * 180/M_PI;
+     debug.printf("ACC: %6.2f %6.2f %6.2f Heading: %6.2f %6.2f\n",acc.x,acc.y,acc.z,hdgV,hdg);
+     wait(0.1);
+   }
+ }
+ 
\ No newline at end of file

--- a/mbed.bld	Tue Nov 30 14:42:07 2010 +0000
+++ b/mbed.bld	Sun May 06 05:14:30 2012 +0000
@@ -1,1 +1,1 @@
-http://mbed.org/users/mbed_official/code/mbed/builds/e2ac27c8e93e
+http://mbed.org/users/mbed_official/code/mbed/builds/737756e0b479