Revision 0:9b3ea4450259, committed 2011-02-20

Comitter:

mkanli

Date:

Sun Feb 20 08:11:35 2011 +0000

Commit message:

First cut

Changed in this revision

diff -r 000000000000 -r 9b3ea4450259 DimEngAcc3D.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DimEngAcc3D.cpp	Sun Feb 20 08:11:35 2011 +0000
@@ -0,0 +1,105 @@
+/**
+ * @file
+ * @section LICENSE
+ * Copyright (c) 2010 Mustafa Ozgur Kanli.
+ *
+ * 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.
+ *
+ * @section Description
+ * Implementation of MaxSonar class.
+ */
+
+#include "mbed.h"
+#include "DimEngAcc3D.h"
+
+DimEngAcc3D::DimEngAcc3D(PinName pin_x, PinName pin_y, PinName pin_z) {
+
+    // Set defaults.
+    initFromVoltage(3.3);
+    this->ain_x = NULL;
+    this->ain_y = NULL;
+    this->ain_z = NULL;
+
+    // Create analog inputs as required.
+    if (pin_x != NC)
+        this->ain_x = new AnalogIn(pin_x);
+
+    if (pin_y != NC)
+        this->ain_y = new AnalogIn(pin_y);
+
+    if (pin_z != NC)
+        this->ain_z = new AnalogIn(pin_z);
+
+}
+
+DimEngAcc3D::~DimEngAcc3D(void) {
+
+    if (this->ain_x != NULL)
+        delete this->ain_x;
+
+    if (this->ain_y != NULL)
+        delete this->ain_y;
+
+    if (this->ain_z != NULL)
+        delete this->ain_z;
+}
+
+void DimEngAcc3D::initFromVoltage(float voltage) {
+    /*
+     * The equation was obtained from the linear relationship
+     * of the sensitivity and input/reference voltage and two
+     * pairs of sensitivity & voltage value pairs:
+     * 195 mV/g @ 2V and 360mV @ 3.6V
+     *
+     * s = sensitivity (V/g)
+     * v = reference voltage (V)
+     * s = 0.103125*v - 0.01125
+     */
+    this->ref_voltage = voltage;
+    this->zero_point = this->ref_voltage / 2.0;
+    this->sensitivity = (0.103125 * this->ref_voltage) - 0.01125;
+    this->x = this->zero_point;
+    this->y = this->zero_point;
+    this->z = this->zero_point;
+    
+    printf("ref: %f, zero: %f, sens: %f \r\n", this->ref_voltage, this->zero_point, this->sensitivity);
+}
+
+void DimEngAcc3D::setVoltage(float voltage) {
+    initFromVoltage(voltage);
+}
+
+void DimEngAcc3D::read(void) {
+
+    // Read the acceleration outputs.
+    if (this->ain_x != NULL)
+        this->x = this->ain_x->read() * this->ref_voltage;
+
+    if (this->ain_y != NULL)
+        this->y = this->ain_y->read() * this->ref_voltage;
+
+    if (this->ain_z != NULL)
+        this->z = this->ain_z->read() * this->ref_voltage;
+
+    // Convert raw voltage measurements to m/s/s
+    this->x = ACC_G * (this->x - this->zero_point) / this->sensitivity;
+    this->y = ACC_G * (this->y - this->zero_point) / this->sensitivity;
+    this->z = ACC_G * (this->z - this->zero_point) / this->sensitivity;
+}
+

diff -r 000000000000 -r 9b3ea4450259 DimEngAcc3D.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DimEngAcc3D.h	Sun Feb 20 08:11:35 2011 +0000
@@ -0,0 +1,119 @@
+/**
+ * @file
+ * @section LICENSE
+ * Copyright (c) 2010 Mustafa Ozgur Kanli.
+ *
+ * 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.
+ *
+ * @section Description
+ * This class provides an object to obtain 3D acceleration measurements from a
+ * Dimension Engineering Buffered +-3g Tri-axis Accelerometer. This device uses
+ * the ADXL330. Measurements are obtained using 3 analog inputs.
+ *
+ */
+#ifndef DIMENG_ACC3D_H_
+#define DIMENG_ACC3D_H_
+
+#include "mbed.h"
+
+/**
+ * Acceleration due to gravity at sea level on Earth (m/s/s).
+ */
+#define ACC_G	9.80665
+
+/**
+ * Class to read acceleration measurements from Dimension Engineering
+ * Buffered +-3g Tri-axis Accelerometer device.
+ *
+ * Example
+ * @code
+ * #include "mbed.h"
+ * #include "DimEngAcc3D.h"
+ *
+ * int main() {
+ *     DimEngAcc3D *acc;
+ *
+ *     // Create and configure object for 3.3V powered device,
+ *     acc = new DimEngAcc3D(p18, p19, p20);
+ *     acc->setVoltage(3.3);
+ *
+ *     while(1) {
+ *         // Read.
+ *         acc->read();
+ *
+ *         // Print and delay 0.5s.
+ *         printf("%.3f, %.3f, %.3f\r\n", acc->x, acc->y, acc->z);
+ *         wait(0.5);
+ *     }
+ * }
+ * @endcode
+ */
+class DimEngAcc3D {
+
+private:
+    float ref_voltage;          //!< Supply/reference voltage (V).
+    float zero_point;			//!< Zero g voltage output (V).
+    float sensitivity;          //!< Sensitivity at reference voltage (V/g).
+    AnalogIn *ain_x;            //!< For analog reads of acceleration in x axis.
+    AnalogIn *ain_y;            //!< For analog reads of acceleration in y axis.
+    AnalogIn *ain_z;            //!< For analog reads of acceleration in z axis.
+
+    /**
+     * Initialize private variables according to the specified
+     * reference voltage
+     * @param   voltage The specified voltage.
+     */
+    void initFromVoltage(float voltage);
+
+public:
+    float x;					//!< Most recent acceleration in x axis (m/s/s).
+    float y;					//!< Most recent acceleration in y axis (m/s/s).
+    float z;					//!< Most recent acceleration in z axis (m/s/s).
+
+    /**
+     * Constructor.
+     *
+     * @param   pin_x    Pin connected to output x of device.
+     * @param   pin_y    Pin connected to output y of device.
+    * @param   pin_z    Pin connected to output z of device.
+     * @note    Unused/unconnected outputs may be specified as NC.
+     */
+    DimEngAcc3D(PinName pin_x, PinName pin_y, PinName pin_z);
+
+    /**
+     * Destructor.
+     */
+    ~DimEngAcc3D(void);
+
+    /**
+     * Specify the supply voltage used by the device.
+     *
+     * @param   voltage The specified voltage (default 3.3)
+     * @note    This is important for correct conversion of the voltage
+     *          from output pins of device into acceleration in m/s/s.
+     */
+    void setVoltage(float voltage);
+
+    /**
+     * Read acceleration and store in x, y & z.
+     */
+    void read(void);
+};
+
+#endif