MMA7361 Class Reference

API for the DFRobot MMA7361 Analog Accelerometer. More...

Detailed Description

• ID: mma7361
• Name: Triaxial Analog Accelerometer
• Category: accelerometer
• Manufacturer: dfrobot
• Connection: ainput gpio
• Link: http://www.dfrobot.com/index.php?route=product/product&path=36&product_id=507#.V7YEj99ytNJ

This library was tested with the DFRobot MMA7361 Analog Accelerometer. It supports 3 Axes with a selectable 1.5G and 6G sensitivity.

  // Instantiate a MMA7361 sensor on analog pins A0 (X), A1 (Y) A2
  // (Z), selftest pin on D2, sleep pin on D3 nd an analog reference
  // value of 5.0.  The freefall pin and the range pin are unused
  // (-1).
  upm::MMA7361 *sensor = new upm::MMA7361(0, 1, 2, 2, 3, -1, -1, 5.0);

  // 1.5g (true = 6g)
  sensor->setRange(false);

  // Every 10th of a second, update and print values

  while (shouldRun)
    {
      sensor->update();

      float x, y, z;

      sensor->getAcceleration(&x, &y, &z);
      cout << "Acceleration x = "
           << x
           << " y = "
           << y
           << "z = "
           << z
           << endl;

      sensor->getVolts(&x, &y, &z);
      cout << "Volts x = "
           << x
           << " y = "
           << y
           << "z = "
           << z
           << endl;

      cout << endl;

      usleep(100000);
    }

Public Member Functions
	MMA7361 (int x_pin, int y_pin, int z_pin, int selftest_pin, int sleep_pin, int freefall_pin, int range_pin, float a_ref=5.0)
	~MMA7361 ()
void	setRange (bool range)
void	setSleep (bool sleep)
bool	isInFreefall ()
void	enableSelftest (bool enable)
void	update ()
void	setOffset (float x, float y, float z)
void	setScale (float x, float y, float z)
void	getAcceleration (float *x, float *y, float *z)
float *	getAcceleration ()
void	getVolts (float *x, float *y, float *z)
float *	getVolts ()
void	getNormalized (float *x, float *y, float *z)
float *	getNormalized ()

Protected Attributes
mma7361_context	m_mma7361

Constructor & Destructor Documentation

MMA7361	(	int	x_pin,
		int	y_pin,
		int	z_pin,
		int	selftest_pin,
		int	sleep_pin,
		int	freefall_pin,
		int	range_pin,
		float	a_ref = 5.0
	)

MMA7361 object constructor

Parameters

x_pin	Analog pin to use for X axis. -1 to disable.
y_pin	Analog pin to use for Y axis. -1 to disable.
z_pin	Analog pin to use for Z axis. -1 to disable.
selftest_pin	GPIO pin to use for self test. -1 to disable.
sleep_pin	GPIO pin to use for sleep function. -1 to disable.
freefall_pin	GPIO pin to use for free fall (0g) detection. -1 to disable.
range_pin	GPIO pin to select range (1.5g or 6g). -1 to disable.
a_ref	The analog reference voltage in use. Default 5.0.

~MMA7361

(

)

MMA7361 object destructor

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Member Function Documentation

void setRange

(

bool

range

)

Set the range of the device. This device supports two G ranges: 1.5 and 6. The default is 1.5G.

Parameters

range

true for 6G, false for 1.5G

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void setSleep

(

bool

sleep

)

Set sleep mode. When in sleep mode the sensor uses minimal power.

Parameters

sleep

true to go into sleep mode, false to wake up

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bool isInFreefall

(

)

Get freefall detection status.

Returns

true if a freefall condition is detected, false otherwise.

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void enableSelftest

(

bool

enable

)

Enable self test mode.

Parameters

enable

true to enable the self test mode, false otherwise.

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void update

(

void

)

Read the sensor status an update internal state. update() must have been called before calling getAcceleration(), getNormalized(), or getVolts().

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void setOffset	(	float	x,
		float	y,
		float	z
	)

Set sensor offset. This offset is applied to the return values before scaling. Default is 0.0.

Parameters

x	Offset to apply to X value
y	Offset to apply to Y value
z	Offset to apply to Z value

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void setScale	(	float	x,
		float	y,
		float	z
	)

Set sensor scale. The acceleration return values are scaled by this value before the offset is applied. Default is 1.0.

Parameters

x	Scale to apply to X value
y	Scale to apply to Y value
z	Scale to apply to Z value

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void getAcceleration	(	float *	x,
		float *	y,
		float *	z
	)

Get computed acceleration from the sensor. update() must have been called prior to calling this function.

Parameters

x	a pointer in which X acceleration data will be returned
y	a pointer in which Y acceleration data will be returned
z	a pointer in which Z acceleration data will be returned

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float * getAcceleration

(

)

Get computed acceleration from the sensor. update() must have been called prior to calling this function.

Returns

a pointer to a statically allocated array of 3 floats containing the X, Y, and Z componenets.

void getVolts	(	float *	x,
		float *	y,
		float *	z
	)

Get the measured volts from the sensor. update() must have been called prior to calling this function.

Parameters

x	a pointer in which X volt data will be returned
y	a pointer in which Y volt data will be returned
z	a pointer in which Z volt data will be returned

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float * getVolts

(

)

Get the measured volts from the sensor. update() must have been called prior to calling this function.

Returns

a pointer to a statically allocated array of 3 floats containing the X, Y, and Z componenets.

void getNormalized	(	float *	x,
		float *	y,
		float *	z
	)

Get the normalized ADC values from the sensor. update() must have been called prior to calling this function.

Parameters

x	a pointer in which X normalized ADC data will be returned
y	a pointer in which Y normalized ADC data will be returned
z	a pointer in which Z normalized ADC data will be returned

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float * getNormalized

(

)

Get the normalized ADC values from the sensor. update() must have been called prior to calling this function.

Returns

a pointer to a statically allocated array of 3 ints containing the X, Y, and Z componenets.

Collaboration diagram for MMA7361:

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The documentation for this class was generated from the following files:

• src/mma7361/mma7361.hpp
• src/mma7361/mma7361.cxx