Perl - Accelerometer Bricklet

This is the description of the Perl API bindings for the Accelerometer Bricklet. General information and technical specifications for the Accelerometer Bricklet are summarized in its hardware description.

An installation guide for the Perl API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Simple

Download (example_simple.pl)

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#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletAccelerometer;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Accelerometer Bricklet

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $a = Tinkerforge::BrickletAccelerometer->new(&UID, $ipcon); # Create device object

$ipcon->connect(&HOST, &PORT); # Connect to brickd
# Don't use device before ipcon is connected

# Get current acceleration
my ($x, $y, $z) = $a->get_acceleration();

print "Acceleration [X]: " . $x/1000.0 . " g\n";
print "Acceleration [Y]: " . $y/1000.0 . " g\n";
print "Acceleration [Z]: " . $z/1000.0 . " g\n";

print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();

Callback

Download (example_callback.pl)

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#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletAccelerometer;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Accelerometer Bricklet

# Callback subroutine for acceleration callback
sub cb_acceleration
{
    my ($x, $y, $z) = @_;

    print "Acceleration [X]: " . $x/1000.0 . " g\n";
    print "Acceleration [Y]: " . $y/1000.0 . " g\n";
    print "Acceleration [Z]: " . $z/1000.0 . " g\n";
    print "\n";
}

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $a = Tinkerforge::BrickletAccelerometer->new(&UID, $ipcon); # Create device object

$ipcon->connect(&HOST, &PORT); # Connect to brickd
# Don't use device before ipcon is connected

# Register acceleration callback to subroutine cb_acceleration
$a->register_callback($a->CALLBACK_ACCELERATION, 'cb_acceleration');

# Set period for acceleration callback to 1s (1000ms)
# Note: The acceleration callback is only called every second
#       if the acceleration has changed since the last call!
$a->set_acceleration_callback_period(1000);

print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();

Threshold

Download (example_threshold.pl)

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#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletAccelerometer;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Accelerometer Bricklet

# Callback subroutine for acceleration reached callback
sub cb_acceleration_reached
{
    my ($x, $y, $z) = @_;

    print "Acceleration [X]: " . $x/1000.0 . " g\n";
    print "Acceleration [Y]: " . $y/1000.0 . " g\n";
    print "Acceleration [Z]: " . $z/1000.0 . " g\n";
    print "\n";
}

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $a = Tinkerforge::BrickletAccelerometer->new(&UID, $ipcon); # Create device object

$ipcon->connect(&HOST, &PORT); # Connect to brickd
# Don't use device before ipcon is connected

# Get threshold callbacks with a debounce time of 10 seconds (10000ms)
$a->set_debounce_period(10000);

# Register acceleration reached callback to subroutine cb_acceleration_reached
$a->register_callback($a->CALLBACK_ACCELERATION_REACHED, 'cb_acceleration_reached');

# Configure threshold for acceleration "greater than 2 g, 2 g, 2 g"
$a->set_acceleration_callback_threshold('>', 2*1000, 0, 2*1000, 0, 2*1000, 0);

print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();

API

Generally, every subroutine of the Perl bindings can report an error as Tinkerforge::Error object via croak(). The object has a get_code() and a get_message() subroutine. There are different error code:

  • Error->ALREADY_CONNECTED = 11
  • Error->NOT_CONNECTED = 12
  • Error->CONNECT_FAILED = 13
  • Error->INVALID_FUNCTION_ID = 21
  • Error->TIMEOUT = 31
  • Error->INVALID_PARAMETER = 41
  • Error->FUNCTION_NOT_SUPPORTED = 42
  • Error->UNKNOWN_ERROR = 43
  • Error->STREAM_OUT_OF_SYNC = 51
  • Error->INVALID_UID = 61
  • Error->NON_ASCII_CHAR_IN_SECRET = 71
  • Error->WRONG_DEVICE_TYPE = 81
  • Error->DEVICE_REPLACED = 82
  • Error->WRONG_RESPONSE_LENGTH = 83

All functions listed below are thread-safe.

Basic Functions

BrickletAccelerometer->new($uid, $ipcon)
Parameters:
  • $uid – Type: string
  • $ipcon – Type: IPConnection
Returns:
  • $accelerometer – Type: BrickletAccelerometer

Creates an object with the unique device ID $uid:

$accelerometer = BrickletAccelerometer->new("YOUR_DEVICE_UID", $ipcon);

This object can then be used after the IP Connection is connected.

BrickletAccelerometer->get_acceleration()
Return Array:
  • 0: $x – Type: int, Unit: 1/1000 gₙ, Range: ?
  • 1: $y – Type: int, Unit: 1/1000 gₙ, Range: ?
  • 2: $z – Type: int, Unit: 1/1000 gₙ, Range: ?

Returns the acceleration in x, y and z direction. The values are given in gₙ/1000 (1gₙ = 9.80665m/s²). The range is configured with set_configuration().

If you want to get the acceleration periodically, it is recommended to use the CALLBACK_ACCELERATION callback and set the period with set_acceleration_callback_period().

BrickletAccelerometer->get_temperature()
Returns:
  • $temperature – Type: int, Unit: 1 °C, Range: [-103 to 152]

Returns the temperature of the accelerometer.

BrickletAccelerometer->led_on()
Returns:
  • undef

Enables the LED on the Bricklet.

BrickletAccelerometer->led_off()
Returns:
  • undef

Disables the LED on the Bricklet.

BrickletAccelerometer->is_led_on()
Returns:
  • $on – Type: bool, Default: 0

Returns true if the LED is enabled, false otherwise.

Advanced Functions

BrickletAccelerometer->set_configuration($data_rate, $full_scale, $filter_bandwidth)
Parameters:
  • $data_rate – Type: int, Range: See constants, Default: 6
  • $full_scale – Type: int, Range: See constants, Default: 1
  • $filter_bandwidth – Type: int, Range: See constants, Default: 2
Returns:
  • undef

Configures the data rate, full scale range and filter bandwidth. Possible values are:

  • Data rate of 0Hz to 1600Hz.
  • Full scale range of ±2gₙ up to ±16gₙ.
  • Filter bandwidth between 50Hz and 800Hz.

Decreasing data rate or full scale range will also decrease the noise on the data.

The following constants are available for this function:

For $data_rate:

  • BrickletAccelerometer->DATA_RATE_OFF = 0
  • BrickletAccelerometer->DATA_RATE_3HZ = 1
  • BrickletAccelerometer->DATA_RATE_6HZ = 2
  • BrickletAccelerometer->DATA_RATE_12HZ = 3
  • BrickletAccelerometer->DATA_RATE_25HZ = 4
  • BrickletAccelerometer->DATA_RATE_50HZ = 5
  • BrickletAccelerometer->DATA_RATE_100HZ = 6
  • BrickletAccelerometer->DATA_RATE_400HZ = 7
  • BrickletAccelerometer->DATA_RATE_800HZ = 8
  • BrickletAccelerometer->DATA_RATE_1600HZ = 9

For $full_scale:

  • BrickletAccelerometer->FULL_SCALE_2G = 0
  • BrickletAccelerometer->FULL_SCALE_4G = 1
  • BrickletAccelerometer->FULL_SCALE_6G = 2
  • BrickletAccelerometer->FULL_SCALE_8G = 3
  • BrickletAccelerometer->FULL_SCALE_16G = 4

For $filter_bandwidth:

  • BrickletAccelerometer->FILTER_BANDWIDTH_800HZ = 0
  • BrickletAccelerometer->FILTER_BANDWIDTH_400HZ = 1
  • BrickletAccelerometer->FILTER_BANDWIDTH_200HZ = 2
  • BrickletAccelerometer->FILTER_BANDWIDTH_50HZ = 3
BrickletAccelerometer->get_configuration()
Return Array:
  • 0: $data_rate – Type: int, Range: See constants, Default: 6
  • 1: $full_scale – Type: int, Range: See constants, Default: 1
  • 2: $filter_bandwidth – Type: int, Range: See constants, Default: 2

Returns the configuration as set by set_configuration().

The following constants are available for this function:

For $data_rate:

  • BrickletAccelerometer->DATA_RATE_OFF = 0
  • BrickletAccelerometer->DATA_RATE_3HZ = 1
  • BrickletAccelerometer->DATA_RATE_6HZ = 2
  • BrickletAccelerometer->DATA_RATE_12HZ = 3
  • BrickletAccelerometer->DATA_RATE_25HZ = 4
  • BrickletAccelerometer->DATA_RATE_50HZ = 5
  • BrickletAccelerometer->DATA_RATE_100HZ = 6
  • BrickletAccelerometer->DATA_RATE_400HZ = 7
  • BrickletAccelerometer->DATA_RATE_800HZ = 8
  • BrickletAccelerometer->DATA_RATE_1600HZ = 9

For $full_scale:

  • BrickletAccelerometer->FULL_SCALE_2G = 0
  • BrickletAccelerometer->FULL_SCALE_4G = 1
  • BrickletAccelerometer->FULL_SCALE_6G = 2
  • BrickletAccelerometer->FULL_SCALE_8G = 3
  • BrickletAccelerometer->FULL_SCALE_16G = 4

For $filter_bandwidth:

  • BrickletAccelerometer->FILTER_BANDWIDTH_800HZ = 0
  • BrickletAccelerometer->FILTER_BANDWIDTH_400HZ = 1
  • BrickletAccelerometer->FILTER_BANDWIDTH_200HZ = 2
  • BrickletAccelerometer->FILTER_BANDWIDTH_50HZ = 3
BrickletAccelerometer->get_identity()
Return Array:
  • 0: $uid – Type: string, Length: up to 8
  • 1: $connected_uid – Type: string, Length: up to 8
  • 2: $position – Type: char, Range: ['a' to 'h', 'z']
  • 3: @hardware_version – Type: [int, ...], Length: 3
    • 0: $major – Type: int, Range: [0 to 255]
    • 1: $minor – Type: int, Range: [0 to 255]
    • 2: $revision – Type: int, Range: [0 to 255]
  • 4: @firmware_version – Type: [int, ...], Length: 3
    • 0: $major – Type: int, Range: [0 to 255]
    • 1: $minor – Type: int, Range: [0 to 255]
    • 2: $revision – Type: int, Range: [0 to 255]
  • 5: $device_identifier – Type: int, Range: [0 to 216 - 1]

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always as position 'z'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

BrickletAccelerometer->register_callback($callback_id, $function)
Parameters:
  • $callback_id – Type: int
  • $function – Type: string
Returns:
  • undef

Registers the given $function name with the given $callback_id.

The available callback IDs with corresponding function signatures are listed below.

BrickletAccelerometer->set_acceleration_callback_period($period)
Parameters:
  • $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Returns:
  • undef

Sets the period with which the CALLBACK_ACCELERATION callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_ACCELERATION callback is only triggered if the acceleration has changed since the last triggering.

BrickletAccelerometer->get_acceleration_callback_period()
Returns:
  • $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by set_acceleration_callback_period().

BrickletAccelerometer->set_acceleration_callback_threshold($option, $min_x, $max_x, $min_y, $max_y, $min_z, $max_z)
Parameters:
  • $option – Type: char, Range: See constants, Default: 'x'
  • $min_x – Type: int, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • $max_x – Type: int, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • $min_y – Type: int, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • $max_y – Type: int, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • $min_z – Type: int, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • $max_z – Type: int, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
Returns:
  • undef

Sets the thresholds for the CALLBACK_ACCELERATION_REACHED callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the acceleration is outside the min and max values
'i' Callback is triggered when the acceleration is inside the min and max values
'<' Callback is triggered when the acceleration is smaller than the min value (max is ignored)
'>' Callback is triggered when the acceleration is greater than the min value (max is ignored)

The following constants are available for this function:

For $option:

  • BrickletAccelerometer->THRESHOLD_OPTION_OFF = 'x'
  • BrickletAccelerometer->THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletAccelerometer->THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletAccelerometer->THRESHOLD_OPTION_SMALLER = '<'
  • BrickletAccelerometer->THRESHOLD_OPTION_GREATER = '>'
BrickletAccelerometer->get_acceleration_callback_threshold()
Return Array:
  • 0: $option – Type: char, Range: See constants, Default: 'x'
  • 1: $min_x – Type: int, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • 2: $max_x – Type: int, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • 3: $min_y – Type: int, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • 4: $max_y – Type: int, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • 5: $min_z – Type: int, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • 6: $max_z – Type: int, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0

Returns the threshold as set by set_acceleration_callback_threshold().

The following constants are available for this function:

For $option:

  • BrickletAccelerometer->THRESHOLD_OPTION_OFF = 'x'
  • BrickletAccelerometer->THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletAccelerometer->THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletAccelerometer->THRESHOLD_OPTION_SMALLER = '<'
  • BrickletAccelerometer->THRESHOLD_OPTION_GREATER = '>'
BrickletAccelerometer->set_debounce_period($debounce)
Parameters:
  • $debounce – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100
Returns:
  • undef

Sets the period with which the threshold callback

is triggered, if the threshold

keeps being reached.

BrickletAccelerometer->get_debounce_period()
Returns:
  • $debounce – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Returns the debounce period as set by set_debounce_period().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the register_callback() function of the device object. The first parameter is the callback ID and the second parameter the callback function name:

sub my_callback
{
    print "@_[0]";
}

$accelerometer->register_callback(BrickletAccelerometer->CALLBACK_EXAMPLE, 'my_callback')

The callback function will be called from an internal thread of the IP Connection. In contrast to many other programming languages, variables are not automatically shared between threads in Perl. If you want to share a global variable between a callback function and the rest for your program it has to be marked as :shared. See the documentation of the threads::shared Perl module for more details.

The available constants with inherent number and type of parameters are described below.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

BrickletAccelerometer->CALLBACK_ACCELERATION
Callback Parameters:
  • $x – Type: int, Unit: 1/1000 gₙ, Range: ?
  • $y – Type: int, Unit: 1/1000 gₙ, Range: ?
  • $z – Type: int, Unit: 1/1000 gₙ, Range: ?

This callback is triggered periodically with the period that is set by set_acceleration_callback_period(). The parameters are the X, Y and Z acceleration. The range is configured with set_configuration().

The CALLBACK_ACCELERATION callback is only triggered if the acceleration has changed since the last triggering.

BrickletAccelerometer->CALLBACK_ACCELERATION_REACHED
Callback Parameters:
  • $x – Type: int, Unit: 1/1000 gₙ, Range: ?
  • $y – Type: int, Unit: 1/1000 gₙ, Range: ?
  • $z – Type: int, Unit: 1/1000 gₙ, Range: ?

This callback is triggered when the threshold as set by set_acceleration_callback_threshold() is reached. The parameters are the X, Y and Z acceleration. The range is configured with set_configuration().

If the threshold keeps being reached, the callback is triggered periodically with the period as set by set_debounce_period().

Virtual Functions

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

BrickletAccelerometer->get_api_version()
Return Array:
  • 0: @api_version – Type: [int, ...], Length: 3
    • 0: $major – Type: int, Range: [0 to 255]
    • 1: $minor – Type: int, Range: [0 to 255]
    • 2: $revision – Type: int, Range: [0 to 255]

Returns the version of the API definition implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

BrickletAccelerometer->get_response_expected($function_id)
Parameters:
  • $function_id – Type: int, Range: See constants
Returns:
  • $response_expected – Type: bool

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by set_response_expected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For $function_id:

  • BrickletAccelerometer->FUNCTION_SET_ACCELERATION_CALLBACK_PERIOD = 2
  • BrickletAccelerometer->FUNCTION_SET_ACCELERATION_CALLBACK_THRESHOLD = 4
  • BrickletAccelerometer->FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BrickletAccelerometer->FUNCTION_SET_CONFIGURATION = 9
  • BrickletAccelerometer->FUNCTION_LED_ON = 11
  • BrickletAccelerometer->FUNCTION_LED_OFF = 12
BrickletAccelerometer->set_response_expected($function_id, $response_expected)
Parameters:
  • $function_id – Type: int, Range: See constants
  • $response_expected – Type: bool
Returns:
  • undef

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For $function_id:

  • BrickletAccelerometer->FUNCTION_SET_ACCELERATION_CALLBACK_PERIOD = 2
  • BrickletAccelerometer->FUNCTION_SET_ACCELERATION_CALLBACK_THRESHOLD = 4
  • BrickletAccelerometer->FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BrickletAccelerometer->FUNCTION_SET_CONFIGURATION = 9
  • BrickletAccelerometer->FUNCTION_LED_ON = 11
  • BrickletAccelerometer->FUNCTION_LED_OFF = 12
BrickletAccelerometer->set_response_expected_all($response_expected)
Parameters:
  • $response_expected – Type: bool
Returns:
  • undef

Changes the response expected flag for all setter and callback configuration functions of this device at once.

Constants

BrickletAccelerometer->DEVICE_IDENTIFIER

This constant is used to identify a Accelerometer Bricklet.

The get_identity() function and the IPConnection->CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

BrickletAccelerometer->DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Accelerometer Bricklet.