Sensor interface

Data Structures
struct	sensors_sensor
	Sensor defintion structure. More...

Macros
#define	SENSORS_ACTIVATE(sensor)   (sensor).configure(SENSORS_ACTIVE, 1)
	Activates sensor.
#define	SENSORS_DEACTIVATE(sensor)   (sensor).configure(SENSORS_ACTIVE, 0)
	Deactivates sensor.
#define	SENSORS_SENSOR(name, type, value, configure, status)   const struct sensors_sensor name = { type, value, configure, status }
	Defines new sensor. More...
#define	SENSORS_NUM   (sizeof(sensors) / sizeof(struct sensors_sensor *))
	Provides the number of available sensors. More...
#define	SENSORS(...)
	Setup defined sensors. More...

Functions
struct sensors_sensor *	sensors_find (const char *type)
	Returns sensor associated with type name if existing. More...
struct sensors_sensor *	sensors_next (const struct sensors_sensor *s)
	Returns next sensor in sensors list. More...
struct sensors_sensor *	sensors_first (void)
	Returns first sensor in sensors list. More...
void	sensors_changed (const struct sensors_sensor *s)
	To be called from sensor readout interrupt. More...

Default constants for the configure/status API
#define	SENSORS_HW_INIT   128
	internal - used only for (hardware) initialization. More...
#define	SENSORS_ACTIVE   129
	Configuration: activates/deactives sensor: 0 -> turn off, 1 -> turn on. More...
#define	SENSORS_READY   130
	Status query: Returns 1 if sensor is ready.

Detailed Description

Using a sensor

Each sensor has a set of functions for controlling it and query it for its state. Some sensors also generate an events when the sensors change. A sensor must be activated before it generates events or relevant values.

• SENSORS_ACTIVATE(sensor) - activate the sensor
• SENSORS_DEACTIVATE(sensor) - deactivate the sensor
• sensor.value(0) - query the sensor for its last value

• sensors_event - event sent when a sensor has changed (the data argument will referer to the actual sensor)

Example for querying the button:

SENSORS_ACTIVATE(button_sensor) // activate the button sensor
button_sensor::value(0) // the button has been pressed or not

Defining new sensors

Platform designers may need to define new sensors. This sections describes the steps required.

Each sensor requires 3 functions; one for quering data, one for configuring the sensor, and one for requesting status.

static int my_value(int type) {...}
static int my_configure(int type, int value) {...}
static int my_status(int type) {...}

These functions have to adapt the interface described in sensors_sensor.

To create a contiki sensor of them use the SENSORS_SENSOR() macro.

SENSORS_SENSOR(my_sensor, "MY_TYPE", my_value, my_configure, my_status);

Finally add the sensor to your platforms sensor list.

SENSORS(..., &my_sensor, ...);

Macro Definition Documentation

#define SENSORS

(

...

)

Value:

const struct sensors_sensor *sensors[] = {__VA_ARGS__, NULL};       \
unsigned char sensors_flags[SENSORS_NUM]

Setup defined sensors.

Parameters

comma-separated

list of pointers to defined sensors.

SENSORS_SENSOR(acc_sensor, "ACC", acc_val, acc_cfg, acc_status);
SENSORS_SENSOR(battery_sensor, "ACC", battery_val, battery_cfg, battery_status);
SENSORS(accsensor, battery_sensor);

Definition at line 124 of file sensors.h.

#define SENSORS_ACTIVE   129

Configuration: activates/deactives sensor: 0 -> turn off, 1 -> turn on.

Status query: Returns 1 if sensor is active.

Definition at line 92 of file sensors.h.

#define SENSORS_HW_INIT   128

internal - used only for (hardware) initialization.

Definition at line 88 of file sensors.h.

#define SENSORS_NUM   (sizeof(sensors) / sizeof(struct sensors_sensor *))

Provides the number of available sensors.

Definition at line 113 of file sensors.h.

#define SENSORS_SENSOR	(		name,
			type,
			value,
			configure,
			status
	)		const struct sensors_sensor name = { type, value, configure, status }

Defines new sensor.

Parameters

name	of the sensor
String	type name of the sensor
pointer	to sensors value function
pointer	to sensors configure function
pointer	to sensors status function

Definition at line 109 of file sensors.h.

Function Documentation

void sensors_changed

(

const struct sensors_sensor *

s

)

To be called from sensor readout interrupt.

Polls sensor process.

Parameters

s	Reference to the sensor that updated

Definition at line 77 of file sensors.c.

References process_poll().

struct sensors_sensor* sensors_find ( const char *  type )

read

Returns sensor associated with type name if existing.

Parameters

type	Type name (string)

Returns

pointer to sensor

Definition at line 84 of file sensors.c.

References NULL, and sensors_sensor::type.

struct sensors_sensor* sensors_first ( void  )

read

Returns first sensor in sensors list.

Returns

pointer to sensor

Definition at line 65 of file sensors.c.

struct sensors_sensor* sensors_next ( const struct sensors_sensor *  s )

read

Returns next sensor in sensors list.

Returns

pointer to sensor

Definition at line 71 of file sensors.c.