WheelSpeed.h File Reference

#include "../DigitalSensor.h"
#include "../../Utils/WheelLocation.h"

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Classes
struct	WheelSpeed

Functions
void	initWheelSpeed (WheelSpeed *ws, int hz, int port, float radius, int numTeeth, WHEEL_LOCATION location)
	Initialization function for a wheel speed sensor. More...
float	calculateSpeed (WheelSpeed *ws)
	Translates data to speed in mph. More...
int	updateWheelSpeed (Updateable *updateable)
	Updated the speed var in this sensor. More...
void	setTimeInterval (WheelSpeed *ws, float interval)
	Set time interval. More...
void	addPulse (WheelSpeed *wf, int num)
	Add pulses to sensor;. More...

Function Documentation

addPulse()

void addPulse	(	WheelSpeed *	wf,
		int	num
	)

Add pulses to sensor;.

Note

For testing and debugging.

Parameters

ws	A pointer to the WheelSpeed structure.
num	Number of pulses to add.

Definition at line 76 of file WheelSpeed.c.

                                       {
    ws->pulses += num;
}

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calculateSpeed()

float calculateSpeed

(

WheelSpeed *

ws

)

Translates data to speed in mph.

Parameters

ws	A pointer to the WheelSpeed structure.

Returns

The speed in miles per hour.

Definition at line 25 of file WheelSpeed.c.

                                     {
    // Check if the pointer is null
    if (ws == NULL) {
        fprintf(stderr, "Error: Null pointer passed to calculateSpeed\n");
        return -1; // Or handle the error as appropriate
    }
 
    int numTeeth = ws->numTeeth;
    float radius = ws->radius;
    int pulses = ws->pulses;
    float delta = measureInterval(ws->interval);
 
    // Reset pulse count and elapsed time for the next measurement interval
    ws->interval = getCurrentTime();
    ws->pulses = 0;
 
    // Verify inputs
    if (numTeeth <= 0 || radius <= 0.0f || pulses <= 0 || delta <= 0.0) {
        printf("Error: Invalid argument. "
               "NumTeeth = %d, Radius = %.2f, Pulses = %d, Time Delta = %.2f\n",
               numTeeth, radius, pulses, delta);
        return 0.0f;
    }
 
    // Calculations
    float circumference = 2 * M_PI * radius;
    float distancePerPulse = circumference / numTeeth;
    float speedMetersPerSecond = (distancePerPulse * pulses) / delta;
    float speed = convertMpsToMph(speedMetersPerSecond);
 
    return speed;
}

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initWheelSpeed()

void initWheelSpeed	(	WheelSpeed *	ws,
		int	hz,
		int	port,
		float	radius,
		int	numTeeth,
		WHEEL_LOCATION	location
	)

Initialization function for a wheel speed sensor.

Parameters

ws	A pointer to the WheelSpeed structure. @pram hz Rate at which the sensor is called (in hz). @pram port Location of sensor. @pram radius Radius of wheel (in mm). @pram numTeeth Number of teeth on reluctor wheel. @pram location Location of sensor on car.

Definition at line 13 of file WheelSpeed.c.

                                             {
    initDigitalSensor(&ws->base, "Wheel Speed", hz, port, ws);
    ws->base.sensor.updateable.update = updateWheelSpeed;
    ws->radius = radius;
    ws->wheel_location = location;
    ws->numTeeth = numTeeth;
    ws->pulses = 0;
    ws->speed = 0.0f;
    ws->interval = getCurrentTime();
}

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setTimeInterval()

void setTimeInterval	(	WheelSpeed *	ws,
		float	interval
	)

Set time interval.

Note

For testing and debugging.

Parameters

ws	A pointer to the WheelSpeed structure.
interval	Time interval to set.

Definition at line 72 of file WheelSpeed.c.

                                                     {
    ws->interval = interval + getCurrentTime();
}

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updateWheelSpeed()

int updateWheelSpeed

(

Updateable *

updateable

)

Updated the speed var in this sensor.

Parameters

updateable

A pointer to the updateable structure.

Returns

_SUCCESS if the speed was updated, _FAILURE otherwise.

Definition at line 58 of file WheelSpeed.c.

                                             {
    // Cast the updateable pointer to a wheel speed sensor
    Sensor* sensor = (Sensor*)updateable->child;
    DigitalSensor* digitalSensor = (DigitalSensor*)sensor->child;
    WheelSpeed* ws = (WheelSpeed*)digitalSensor->child;
 
    ws->speed = calculateSpeed(ws);
    if (ws->speed < 0) {
        printf("Error: Speed calculation failed\n");
        return _FAILURE;
    }
    return _SUCCESS;
}

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