SRF02 ultrasonic range sensor

Driver for the SRF02 ultrasonic range sensor. More...

Detailed Description

Driver for the SRF02 ultrasonic range sensor.

Files
file	srf02.h
	Driver definitions for the SRF02 ultrasonic ranger.

Data Structures
struct	srf02_t
	Device descriptor for SRF02 sensors. More...

Macros
#define	SRF02_DEFAULT_ADDR   (0xe0) /* 224 decimal */
	Default I2C address of SRF02 sensors.
#define	SRF02_RANGE_DELAY   (70000U)
	The datasheet tells us, that ranging takes 70ms.

Enumerations
enum	srf02_mode_t {   SRF02_MODE_REAL_INCH = 0x50 , SRF02_MODE_REAL_CM = 0x51 , SRF02_MODE_REAL_MS = 0x52 , SRF02_MODE_FAKE_INCH = 0x56 ,   SRF02_MODE_FAKE_CM = 0x57 , SRF02_MODE_FAKE_MS = 0x58 }
	Possible measurement modes of the SRF02 sensor. More...

Functions
int	srf02_init (srf02_t *dev, i2c_t i2c, uint8_t addr)
	Initialize the SRF02 ultrasonic sensor.
int	srf02_trigger (const srf02_t *dev, srf02_mode_t mode)
	Trigger a new measurement.
uint16_t	srf02_read (const srf02_t *dev)
	Read the results of the last ranging operation.
uint16_t	srf02_get_distance (const srf02_t *dev, srf02_mode_t mode)
	Get the distance measured from the SRF02 ultrasonic sensor.
int	srf02_set_addr (srf02_t *dev, uint8_t new_addr)
	Program the given device with a new bus address.

Macro Definition Documentation

SRF02_DEFAULT_ADDR

#define SRF02_DEFAULT_ADDR   (0xe0) /* 224 decimal */

Default I2C address of SRF02 sensors.

Definition at line 38 of file srf02.h.

SRF02_RANGE_DELAY

#define SRF02_RANGE_DELAY   (70000U)

The datasheet tells us, that ranging takes 70ms.

Definition at line 43 of file srf02.h.

Enumeration Type Documentation

srf02_mode_t

enum srf02_mode_t

Possible measurement modes of the SRF02 sensor.

Enumerator
SRF02_MODE_REAL_INCH	result in inches
SRF02_MODE_REAL_CM	result in centimeters
SRF02_MODE_REAL_MS	result in microseconds
SRF02_MODE_FAKE_INCH	result in inches (no pulse send)
SRF02_MODE_FAKE_CM	result in cm (no pulse send)
SRF02_MODE_FAKE_MS	result in ms (no pulse send)

Definition at line 56 of file srf02.h.

Function Documentation

srf02_get_distance()

uint16_t srf02_get_distance	(	const srf02_t *	dev,
		srf02_mode_t	mode
	)

Get the distance measured from the SRF02 ultrasonic sensor.

This function combines the srf02_trigger and the srf02_read functions for simplified usage in simple (single sensor) setups.

Parameters

[in]	dev	device descriptor of an SRF02 sensor
[in]	mode	there are three real ranging modes, which return the result in inches, centimeters or microseconds. Another set of three fake ranging modes do the same but without transmitting the burst

Returns

the ranging result in inches, centimeters or microseconds

srf02_init()

int srf02_init	(	srf02_t *	dev,
		i2c_t	i2c,
		uint8_t	addr
	)

Initialize the SRF02 ultrasonic sensor.

Parameters

[in]	dev	device descriptor of an SRF02 sensor
[in]	i2c	I2C device the sensor is connected to
[in]	addr	I2C address of the sensor

Returns

0 on successful initialization

-1 on error

srf02_read()

uint16_t srf02_read

(

const srf02_t *

dev

)

Read the results of the last ranging operation.

Parameters

[in]

dev

device to read from

Returns

result of the last ranging operation, meaning depends on the mode parameter given to the srf02_trigger function

srf02_set_addr()

int srf02_set_addr	(	srf02_t *	dev,
		uint8_t	new_addr
	)

Program the given device with a new bus address.

Parameters

[in]	dev	device to program
[in]	new_addr	new address to program the given device to

Returns

0 On success, otherwise i2c_write error

srf02_trigger()

int srf02_trigger	(	const srf02_t *	dev,
		srf02_mode_t	mode
	)

Trigger a new measurement.

This function triggers a new ranging operation. After triggering this operation, you have to wait at least 70ms for the result to be ready.

The result of the ranging operation is returned in inches, centimeters or microseconds - depending on the given mode parameter.

Parameters

[in]	dev	device to trigger
[in]	mode	there are three real ranging modes, which return the result in inches, centimeters or microseconds. Another set of three fake ranging modes do the same but without transmitting the burst

Returns

0 On success, otherwise i2c_write error