Software / API Bindings / PHP / API Reference and Examples / Bricklets / Distance US Bricklet 2.0

PHP - Distance US Bricklet 2.0¶

This is the description of the PHP API bindings for the Distance US Bricklet 2.0. General information and technical specifications for the Distance US Bricklet 2.0 are summarized in its hardware description.

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

Examples¶

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

Simple¶

Download (ExampleSimple.php)

<?php

require_once('Tinkerforge/IPConnection.php');
require_once('Tinkerforge/BrickletDistanceUSV2.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletDistanceUSV2;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your Distance US Bricklet 2.0

$ipcon = new IPConnection(); // Create IP connection
$dus = new BrickletDistanceUSV2(UID, $ipcon); // Create device object

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

// Get current distance
$distance = $dus->getDistance();
echo "Distance: " . $distance/10.0 . " cm\n";

echo "Press key to exit\n";
fgetc(fopen('php://stdin', 'r'));
$ipcon->disconnect();

?>

Callback¶

Download (ExampleCallback.php)

<?php

require_once('Tinkerforge/IPConnection.php');
require_once('Tinkerforge/BrickletDistanceUSV2.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletDistanceUSV2;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your Distance US Bricklet 2.0

// Callback function for distance callback
function cb_distance($distance)
{
    echo "Distance: " . $distance/10.0 . " cm\n";
}

$ipcon = new IPConnection(); // Create IP connection
$dus = new BrickletDistanceUSV2(UID, $ipcon); // Create device object

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

// Register distance callback to function cb_distance
$dus->registerCallback(BrickletDistanceUSV2::CALLBACK_DISTANCE, 'cb_distance');

// Set period for distance callback to 0.1s (100ms) without a threshold
$dus->setDistanceCallbackConfiguration(100, FALSE, 'x', 0, 0);

echo "Press ctrl+c to exit\n";
$ipcon->dispatchCallbacks(-1); // Dispatch callbacks forever

?>

Threshold¶

Download (ExampleThreshold.php)

<?php

require_once('Tinkerforge/IPConnection.php');
require_once('Tinkerforge/BrickletDistanceUSV2.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletDistanceUSV2;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your Distance US Bricklet 2.0

// Callback function for distance callback
function cb_distance($distance)
{
    echo "Distance: " . $distance/10.0 . " cm\n";
}

$ipcon = new IPConnection(); // Create IP connection
$dus = new BrickletDistanceUSV2(UID, $ipcon); // Create device object

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

// Register distance callback to function cb_distance
$dus->registerCallback(BrickletDistanceUSV2::CALLBACK_DISTANCE, 'cb_distance');

// Configure threshold for distance "greater than 100 cm"
// with a debounce period of 0.1s (100ms)
$dus->setDistanceCallbackConfiguration(100, FALSE, '>', 100*10, 0);

echo "Press ctrl+c to exit\n";
$ipcon->dispatchCallbacks(-1); // Dispatch callbacks forever

?>

API¶

Functions that return multiple values return them in an associative array.

Basic Functions¶

class BrickletDistanceUSV2(string $uid, IPConnection $ipcon)¶

Parameters:	$uid – Type: string $ipcon – Type: IPConnection
Returns:	$distance_us_v2 – Type: BrickletDistanceUSV2

Creates an object with the unique device ID $uid:

<?php   $distance_us_v2 = new BrickletDistanceUSV2('YOUR_DEVICE_UID', $ipcon);   ?>

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

int BrickletDistanceUSV2::getDistance()¶

Returns:	$distance – Type: int, Unit: 1 mm, Range: [300 to 5000]

Returns the distance.

If you want to get the value periodically, it is recommended to use the CALLBACK_DISTANCE callback. You can set the callback configuration with setDistanceCallbackConfiguration().

void BrickletDistanceUSV2::setUpdateRate(int $update_rate)¶

Parameters:	$update_rate – Type: int, Range: See constants, Default: 0

Sets the update rate to 2 Hz or 10 Hz.

With 2 Hz update rate the noise is about ±1mm, while with 10 Hz update rate the noise increases to about ±5mm.

The following constants are available for this function:

For $update_rate:

BrickletDistanceUSV2::UPDATE_RATE_2_HZ = 0
BrickletDistanceUSV2::UPDATE_RATE_10_HZ = 1

int BrickletDistanceUSV2::getUpdateRate()¶

Returns:	$update_rate – Type: int, Range: See constants, Default: 0

Returns the update rate as set by setUpdateRate().

The following constants are available for this function:

For $update_rate:

BrickletDistanceUSV2::UPDATE_RATE_2_HZ = 0
BrickletDistanceUSV2::UPDATE_RATE_10_HZ = 1

void BrickletDistanceUSV2::setDistanceLEDConfig(int $config)¶

Parameters:	$config – Type: int, Range: See constants, Default: 3

Configures the distance LED to be either turned off, turned on, blink in heartbeat mode or show the distance (brighter = object is nearer).

The following constants are available for this function:

For $config:

BrickletDistanceUSV2::DISTANCE_LED_CONFIG_OFF = 0
BrickletDistanceUSV2::DISTANCE_LED_CONFIG_ON = 1
BrickletDistanceUSV2::DISTANCE_LED_CONFIG_SHOW_HEARTBEAT = 2
BrickletDistanceUSV2::DISTANCE_LED_CONFIG_SHOW_DISTANCE = 3

int BrickletDistanceUSV2::getDistanceLEDConfig()¶

Returns:	$config – Type: int, Range: See constants, Default: 3

Returns the LED configuration as set by setDistanceLEDConfig()

The following constants are available for this function:

For $config:

BrickletDistanceUSV2::DISTANCE_LED_CONFIG_OFF = 0
BrickletDistanceUSV2::DISTANCE_LED_CONFIG_ON = 1
BrickletDistanceUSV2::DISTANCE_LED_CONFIG_SHOW_HEARTBEAT = 2
BrickletDistanceUSV2::DISTANCE_LED_CONFIG_SHOW_DISTANCE = 3

Advanced Functions¶

array BrickletDistanceUSV2::getSPITFPErrorCount()¶

Return Array:	'error_count_ack_checksum' – Type: int, Range: [0 to 2³² - 1] 'error_count_message_checksum' – Type: int, Range: [0 to 2³² - 1] 'error_count_frame' – Type: int, Range: [0 to 2³² - 1] 'error_count_overflow' – Type: int, Range: [0 to 2³² - 1]

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

ACK checksum errors,
message checksum errors,
framing errors and
overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

void BrickletDistanceUSV2::setStatusLEDConfig(int $config)¶

Parameters:	$config – Type: int, Range: See constants, Default: 3

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following constants are available for this function:

For $config:

BrickletDistanceUSV2::STATUS_LED_CONFIG_OFF = 0
BrickletDistanceUSV2::STATUS_LED_CONFIG_ON = 1
BrickletDistanceUSV2::STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
BrickletDistanceUSV2::STATUS_LED_CONFIG_SHOW_STATUS = 3

int BrickletDistanceUSV2::getStatusLEDConfig()¶

Returns:	$config – Type: int, Range: See constants, Default: 3

Returns the configuration as set by setStatusLEDConfig()

The following constants are available for this function:

For $config:

BrickletDistanceUSV2::STATUS_LED_CONFIG_OFF = 0
BrickletDistanceUSV2::STATUS_LED_CONFIG_ON = 1
BrickletDistanceUSV2::STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
BrickletDistanceUSV2::STATUS_LED_CONFIG_SHOW_STATUS = 3

int BrickletDistanceUSV2::getChipTemperature()¶

Returns:	$temperature – Type: int, Unit: 1 °C, Range: [-2¹⁵ to 2¹⁵ - 1]

Returns the temperature as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

void BrickletDistanceUSV2::reset()¶

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

array BrickletDistanceUSV2::getIdentity()¶

Return Array:

Return Array:	'uid' – Type: string, Length: up to 8 'connected_uid' – Type: string, Length: up to 8 'position' – Type: string, Range: ['a' to 'h', 'z'] 'hardware_version' – Type: array(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] 'firmware_version' – Type: array(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] 'device_identifier' – Type: int, Range: [0 to 2¹⁶ - 1]

'uid' – Type: string, Length: up to 8
'connected_uid' – Type: string, Length: up to 8
'position' – Type: string, Range: ['a' to 'h', 'z']
'hardware_version' – Type: array(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]

'firmware_version' – Type: array(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]

'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 at 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¶

void BrickletDistanceUSV2::registerCallback(int $callback_id, callable $callback, mixed $user_data=NULL)¶

Parameters:	$callback_id – Type: int $callback – Type: callable $user_data – Type: mixed

Registers the given $function with the given $callback_id. The optional $user_data will be passed as the last parameter to the function.

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

void BrickletDistanceUSV2::setDistanceCallbackConfiguration(int $period, bool $value_has_to_change, string $option, int $min, int $max)¶

Parameters:	$period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0 $value_has_to_change – Type: bool, Default: FALSE $option – Type: string, Range: See constants, Default: 'x' $min – Type: int, Unit: 1 mm, Range: [0 to 2¹⁶ - 1], Default: 0 $max – Type: int, Unit: 1 mm, Range: [0 to 2¹⁶ - 1], Default: 0

The period is the period with which the CALLBACK_DISTANCE callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the CALLBACK_DISTANCE callback.

The following options are possible:

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

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

The following constants are available for this function:

For $option:

BrickletDistanceUSV2::THRESHOLD_OPTION_OFF = 'x'
BrickletDistanceUSV2::THRESHOLD_OPTION_OUTSIDE = 'o'
BrickletDistanceUSV2::THRESHOLD_OPTION_INSIDE = 'i'
BrickletDistanceUSV2::THRESHOLD_OPTION_SMALLER = '<'
BrickletDistanceUSV2::THRESHOLD_OPTION_GREATER = '>'

array BrickletDistanceUSV2::getDistanceCallbackConfiguration()¶

Return Array:	'period' – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0 'value_has_to_change' – Type: bool, Default: FALSE 'option' – Type: string, Range: See constants, Default: 'x' 'min' – Type: int, Unit: 1 mm, Range: [0 to 2¹⁶ - 1], Default: 0 'max' – Type: int, Unit: 1 mm, Range: [0 to 2¹⁶ - 1], Default: 0

Returns the callback configuration as set by setDistanceCallbackConfiguration().

The following constants are available for this function:

For $option:

BrickletDistanceUSV2::THRESHOLD_OPTION_OFF = 'x'
BrickletDistanceUSV2::THRESHOLD_OPTION_OUTSIDE = 'o'
BrickletDistanceUSV2::THRESHOLD_OPTION_INSIDE = 'i'
BrickletDistanceUSV2::THRESHOLD_OPTION_SMALLER = '<'
BrickletDistanceUSV2::THRESHOLD_OPTION_GREATER = '>'

Callbacks¶

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

<?php

function myCallback($param)
{
    echo $param . "\n";
}

$distance_us_v2->registerCallback(BrickletDistanceUSV2::CALLBACK_EXAMPLE, 'myCallback');

?>

The available constants with corresponding function signatures 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.

int BrickletDistanceUSV2::CALLBACK_DISTANCE¶

<?php   void callback(int $distance [, mixed $user_data])   ?>

Callback Parameters:	$distance – Type: int, Unit: 1 mm, Range: [300 to 5000] $user_data – Type: mixed

This callback is triggered periodically according to the configuration set by setDistanceCallbackConfiguration().

The parameter is the same as getDistance().

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.

array BrickletDistanceUSV2::getAPIVersion()¶

Return Array:	$api_version – Type: array(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.

bool BrickletDistanceUSV2::getResponseExpected(int $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 setResponseExpected(). 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:

BrickletDistanceUSV2::FUNCTION_SET_DISTANCE_CALLBACK_CONFIGURATION = 2
BrickletDistanceUSV2::FUNCTION_SET_UPDATE_RATE = 5
BrickletDistanceUSV2::FUNCTION_SET_DISTANCE_LED_CONFIG = 7
BrickletDistanceUSV2::FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
BrickletDistanceUSV2::FUNCTION_SET_STATUS_LED_CONFIG = 239
BrickletDistanceUSV2::FUNCTION_RESET = 243
BrickletDistanceUSV2::FUNCTION_WRITE_UID = 248

void BrickletDistanceUSV2::setResponseExpected(int $function_id, bool $response_expected)¶

Parameters:	$function_id – Type: int, Range: See constants $response_expected – Type: bool

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.

The following constants are available for this function:

For $function_id:

BrickletDistanceUSV2::FUNCTION_SET_DISTANCE_CALLBACK_CONFIGURATION = 2
BrickletDistanceUSV2::FUNCTION_SET_UPDATE_RATE = 5
BrickletDistanceUSV2::FUNCTION_SET_DISTANCE_LED_CONFIG = 7
BrickletDistanceUSV2::FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
BrickletDistanceUSV2::FUNCTION_SET_STATUS_LED_CONFIG = 239
BrickletDistanceUSV2::FUNCTION_RESET = 243
BrickletDistanceUSV2::FUNCTION_WRITE_UID = 248

void BrickletDistanceUSV2::setResponseExpectedAll(bool $response_expected)¶

Parameters:	$response_expected – Type: bool

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

Internal Functions¶

Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.

int BrickletDistanceUSV2::setBootloaderMode(int $mode)¶

Parameters:	$mode – Type: int, Range: See constants
Returns:	$status – Type: int, Range: See constants

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following constants are available for this function:

For $mode:

BrickletDistanceUSV2::BOOTLOADER_MODE_BOOTLOADER = 0
BrickletDistanceUSV2::BOOTLOADER_MODE_FIRMWARE = 1
BrickletDistanceUSV2::BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
BrickletDistanceUSV2::BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
BrickletDistanceUSV2::BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4

For $status:

BrickletDistanceUSV2::BOOTLOADER_STATUS_OK = 0
BrickletDistanceUSV2::BOOTLOADER_STATUS_INVALID_MODE = 1
BrickletDistanceUSV2::BOOTLOADER_STATUS_NO_CHANGE = 2
BrickletDistanceUSV2::BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
BrickletDistanceUSV2::BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
BrickletDistanceUSV2::BOOTLOADER_STATUS_CRC_MISMATCH = 5

int BrickletDistanceUSV2::getBootloaderMode()¶

Returns:	$mode – Type: int, Range: See constants

Returns the current bootloader mode, see setBootloaderMode().

The following constants are available for this function:

For $mode:

BrickletDistanceUSV2::BOOTLOADER_MODE_BOOTLOADER = 0
BrickletDistanceUSV2::BOOTLOADER_MODE_FIRMWARE = 1
BrickletDistanceUSV2::BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
BrickletDistanceUSV2::BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
BrickletDistanceUSV2::BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4

void BrickletDistanceUSV2::setWriteFirmwarePointer(int $pointer)¶

Parameters:	$pointer – Type: int, Unit: 1 B, Range: [0 to 2³² - 1]

Sets the firmware pointer for writeFirmware(). The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

int BrickletDistanceUSV2::writeFirmware(array $data)¶

Parameters:	$data – Type: array(int, ...), Length: 64, Range: [0 to 255]
Returns:	$status – Type: int, Range: [0 to 255]

Writes 64 Bytes of firmware at the position as written by setWriteFirmwarePointer() before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

void BrickletDistanceUSV2::writeUID(int $uid)¶

Parameters:	$uid – Type: int, Range: [0 to 2³² - 1]

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

int BrickletDistanceUSV2::readUID()¶

Returns:	$uid – Type: int, Range: [0 to 2³² - 1]

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

Constants¶

int BrickletDistanceUSV2::DEVICE_IDENTIFIER¶

This constant is used to identify a Distance US Bricklet 2.0.

The getIdentity() function and the IPConnection::CALLBACK_ENUMERATE callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

string BrickletDistanceUSV2::DEVICE_DISPLAY_NAME¶: This constant represents the human readable name of a Distance US Bricklet 2.0.