PHP - Dust Detector Bricklet

This is the description of the PHP API bindings for the Dust Detector Bricklet. General information and technical specifications for the Dust Detector Bricklet 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)

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<?php

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

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletDustDetector;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your Dust Detector Bricklet

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

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

// Get current dust density
$dust_density = $dd->getDustDensity();
echo "Dust Density: $dust_density µg/m³\n";

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

?>

Callback

Download (ExampleCallback.php)

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<?php

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

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletDustDetector;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your Dust Detector Bricklet

// Callback function for dust density callback
function cb_dustDensity($dust_density)
{
    echo "Dust Density: $dust_density µg/m³\n";
}

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

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

// Register dust density callback to function cb_dustDensity
$dd->registerCallback(BrickletDustDetector::CALLBACK_DUST_DENSITY, 'cb_dustDensity');

// Set period for dust density callback to 1s (1000ms)
// Note: The dust density callback is only called every second
//       if the dust density has changed since the last call!
$dd->setDustDensityCallbackPeriod(1000);

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

?>

Threshold

Download (ExampleThreshold.php)

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<?php

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

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletDustDetector;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your Dust Detector Bricklet

// Callback function for dust density reached callback
function cb_dustDensityReached($dust_density)
{
    echo "Dust Density: $dust_density µg/m³\n";
}

$ipcon = new IPConnection(); // Create IP connection
$dd = new BrickletDustDetector(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)
$dd->setDebouncePeriod(10000);

// Register dust density reached callback to function cb_dustDensityReached
$dd->registerCallback(BrickletDustDetector::CALLBACK_DUST_DENSITY_REACHED,
                      'cb_dustDensityReached');

// Configure threshold for dust density "greater than 10 µg/m³"
$dd->setDustDensityCallbackThreshold('>', 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 BrickletDustDetector(string $uid, IPConnection $ipcon)

Creates an object with the unique device ID $uid:

<?php   $dust_detector = new BrickletDustDetector('YOUR_DEVICE_UID', $ipcon);   ?>

This object can then be used after the IP Connection is connected (see examples above).

int BrickletDustDetector::getDustDensity()

Returns the dust density in µg/m³.

If you want to get the dust density periodically, it is recommended to use the CALLBACK_DUST_DENSITY callback and set the period with setDustDensityCallbackPeriod().

Advanced Functions

void BrickletDustDetector::setMovingAverage(int $average)

Sets the length of a moving averaging for the dust_density.

Setting the length to 0 will turn the averaging completely off. With less averaging, there is more noise on the data.

The range for the averaging is 0-100.

The default value is 100.

int BrickletDustDetector::getMovingAverage()

Returns the length moving average as set by setMovingAverage().

array BrickletDustDetector::getAPIVersion()

Returns the version of the API definition (major, minor, revision) 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 BrickletDustDetector::getResponseExpected(int $function_id)

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 send and errors are silently ignored, because they cannot be detected.

See setResponseExpected() for the list of function ID constants available for this function.

void BrickletDustDetector::setResponseExpected(int $function_id, bool $response_expected)

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 send and errors are silently ignored, because they cannot be detected.

The following function ID constants are available for this function:

  • BrickletDustDetector::FUNCTION_SET_DUST_DENSITY_CALLBACK_PERIOD = 2
  • BrickletDustDetector::FUNCTION_SET_DUST_DENSITY_CALLBACK_THRESHOLD = 4
  • BrickletDustDetector::FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BrickletDustDetector::FUNCTION_SET_MOVING_AVERAGE = 10
void BrickletDustDetector::setResponseExpectedAll(bool $response_expected)

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

array BrickletDustDetector::getIdentity()

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' or 'd'.

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

The returned array has the keys uid, connected_uid, position, hardware_version, firmware_version and device_identifier.

Callback Configuration Functions

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

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 BrickletDustDetector::setDustDensityCallbackPeriod(int $period)

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

The CALLBACK_DUST_DENSITY callback is only triggered if the dust density has changed since the last triggering.

The default value is 0.

int BrickletDustDetector::getDustDensityCallbackPeriod()

Returns the period as set by setDustDensityCallbackPeriod().

void BrickletDustDetector::setDustDensityCallbackThreshold(string $option, int $min, int $max)

Sets the thresholds for the CALLBACK_DUST_DENSITY_REACHED callback.

The following options are possible:

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

The default value is ('x', 0, 0).

The following constants are available for this function:

  • BrickletDustDetector::THRESHOLD_OPTION_OFF = 'x'
  • BrickletDustDetector::THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletDustDetector::THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletDustDetector::THRESHOLD_OPTION_SMALLER = '<'
  • BrickletDustDetector::THRESHOLD_OPTION_GREATER = '>'
array BrickletDustDetector::getDustDensityCallbackThreshold()

Returns the threshold as set by setDustDensityCallbackThreshold().

The following constants are available for this function:

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

The returned array has the keys option, min and max.

void BrickletDustDetector::setDebouncePeriod(int $debounce)

Sets the period in ms with which the threshold callback

is triggered, if the threshold

keeps being reached.

The default value is 100.

int BrickletDustDetector::getDebouncePeriod()

Returns the debounce period as set by setDebouncePeriod().

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";
}

$dust_detector->registerCallback(BrickletDustDetector::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 BrickletDustDetector::CALLBACK_DUST_DENSITY
<?php   void callback(int $dust_density [, mixed $user_data])   ?>

This callback is triggered periodically with the period that is set by setDustDensityCallbackPeriod(). The parameter is the dust density of the sensor.

Der CALLBACK_DUST_DENSITY callback is only triggered if the dust density value has changed since the last triggering.

int BrickletDustDetector::CALLBACK_DUST_DENSITY_REACHED
<?php   void callback(int $dust_density [, mixed $user_data])   ?>

This callback is triggered when the threshold as set by setDustDensityCallbackThreshold() is reached. The parameter is the dust density of the sensor.

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

Constants

int BrickletDustDetector::DEVICE_IDENTIFIER

This constant is used to identify a Dust Detector Bricklet.

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

string BrickletDustDetector::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Dust Detector Bricklet.