e_acc.c File Reference

Accessing the accelerometer data. More...

#include "math.h"
#include "e_acc.h"
#include "e_ad_conv.h"
#include "../../motor_led/e_epuck_ports.h"
#include "../../motor_led/advance_one_timer/e_led.h"
#include <stdlib.h>

Functions
int	e_get_acc (unsigned int captor)
	Read the last value of a given accelerator axes.
int	e_get_acc_filtered (unsigned int captor, unsigned int filter_size)
	Read the value of a channel, filtered by an averaging filter.
void	calculate_acc_raw (void)
	read the x, y, z values, apply an averaging filter and finaly subbstract the center values.
void	calculate_acc_spherical (void)
	calculate the intensity of the acceleration vector, and the Euler's angles
void	e_acc_calibr (void)
	initialize de ad converter and calculate the zero values
TypeAccSpheric	e_read_acc_spheric (void)
	calculate and return the accel. in spherical coord
float	e_read_inclination (void)
	calculate and return the inclination angle
float	e_read_orientation (void)
	calculate and return the orientation angle
float	e_read_acc (void)
	calculate and return the intensity of the acceleration
TypeAccRaw	e_read_acc_xyz (void)
	calculate and return acceleration on the x,y,z axis
int	e_read_acc_x (void)
	calculate and return acceleration on the x axis
int	e_read_acc_y (void)
	calculate and return acceleration on the y axis
int	e_read_acc_z (void)
	calculate and return acceleration on the z axis
void	e_display_angle (void)
	light the led according to the orientation angle
Variables
int	e_acc_scan [3][ACC_SAMP_NB]
unsigned int	e_last_acc_scan_id
static int	angle_mem = 0
static int	centre_x = 0
static int	centre_y = 0
static int	centre_z = 2000
static int	acc_x
static int	acc_y
static int	acc_z
static float	acceleration
static float	orientation
static float	inclination

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Detailed Description

Accessing the accelerometer data.

The functions of this file are made to deal with the accelerometer data. You can know the magnitude, the orientation, the inclination, ... of the acceleration that the e-puck is enduring.

Two structures are used:

• TypeAccSpheric to store the acceleration data on sherical coordinates.
• TypeAccRaw to store the acceleration data on cartesian coordinates.

A little exemple to read the accelerator.

 #include <p30f6014A.h>
 #include <motor_led/e_epuck_ports.h>
 #include <motor_led/e_init_port.h>
 #include <a_d/advance_ad_scan/e_ad_conv.h>
 #include <a_d/advance_ad_scan/e_acc.h>
 
 int main(void)
 {
        int z;
        e_init_port();
        e_init_ad_scan();
        while(1)
        {
                long i;
                        z = e_get_acc(2);
                if(z < 2100)    //LED4 on if e-puck is on the back
                {
                        LED0 = 0;
                        LED4 = 1;
                }
                else            //LED0 on if e-puck is on his wells
                {
                        LED0 = 1;
                        LED4 = 0;
                }
                for(i=0; i<100000; i++) { asm("nop"); }
                }
  }

Author:

Code: Borter Jean-Joel
Doc: Jonathan Besuchet

---

Function Documentation

void calculate_acc_raw

(

void

)

read the x, y, z values, apply an averaging filter and finaly subbstract the center values.

void calculate_acc_spherical

(

void

)

calculate the intensity of the acceleration vector, and the Euler's angles

void e_acc_calibr

(

void

)

initialize de ad converter and calculate the zero values

It reads two times the average_size to avoid edge effects then it reads 100 values and average them to initiate the "zero" value of the accelerometer

void e_display_angle

(

void

)

light the led according to the orientation angle

int e_get_acc

(

unsigned int

captor

)

Read the last value of a given accelerator axes.

Parameters:

captor

ID of the AD channel to read (must be 0 = x, 1 = y or 2 = z)

Returns:

value filtered channel's value

int e_get_acc_filtered	(	unsigned int	captor,
		unsigned int	filter_size
	)

Read the value of a channel, filtered by an averaging filter.

Parameters:

	captor	ID of the AD channel to read (must be 0 to 2)
	filter_size	size of the filter (must be between 1 and SAMPLE_NUMBER)

Returns:

value filtered channel's value

float e_read_acc

(

void

)

calculate and return the intensity of the acceleration

Returns:

intensity of the acceleration vector

TypeAccSpheric e_read_acc_spheric

(

void

)

calculate and return the accel. in spherical coord

Returns:

acceleration in spherical coord

See also:

TypeAccSpheric

int e_read_acc_x

(

void

)

calculate and return acceleration on the x axis

Returns:

acceleration on the x axis

TypeAccRaw e_read_acc_xyz

(

void

)

calculate and return acceleration on the x,y,z axis

Returns:

acceleration on the x,y,z axis

See also:

TypeAccRaw

int e_read_acc_y

(

void

)

calculate and return acceleration on the y axis

Returns:

acceleration on the y axis

int e_read_acc_z

(

void

)

calculate and return acceleration on the z axis

Returns:

acceleration on the z axis

float e_read_inclination

(

void

)

calculate and return the inclination angle

Returns:

inclination angle of the robot

float e_read_orientation

(

void

)

calculate and return the orientation angle

Returns:

orientation of the accel vector

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Variable Documentation

int acc_x [static]

int acc_y [static]

int acc_z [static]

float acceleration [static]

int angle_mem = 0 [static]

int centre_x = 0 [static]

int centre_y = 0 [static]

int centre_z = 2000 [static]

int e_acc_scan[3][ACC_SAMP_NB]

Array to store the acc values

unsigned int e_last_acc_scan_id

float inclination [static]

float orientation [static]

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