PHP - Temperature Bricklet

This is the description of the PHP API bindings for the Temperature Bricklet. General information and technical specifications for the Temperature 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/BrickletTemperature.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletTemperature;

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

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

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

// Get current temperature
$temperature = $t->getTemperature();
echo "Temperature: " . $temperature/100.0 . " °C\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/BrickletTemperature.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletTemperature;

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

// Callback function for temperature callback
function cb_temperature($temperature)
{
    echo "Temperature: " . $temperature/100.0 . " °C\n";
}

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

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

// Register temperature callback to function cb_temperature
$t->registerCallback(BrickletTemperature::CALLBACK_TEMPERATURE, 'cb_temperature');

// Set period for temperature callback to 1s (1000ms)
// Note: The temperature callback is only called every second
//       if the temperature has changed since the last call!
$t->setTemperatureCallbackPeriod(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/BrickletTemperature.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletTemperature;

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

// Callback function for temperature reached callback
function cb_temperatureReached($temperature)
{
    echo "Temperature: " . $temperature/100.0 . " °C\n";
    echo "It is too hot, we need air conditioning!\n";
}

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

// Register temperature reached callback to function cb_temperatureReached
$t->registerCallback(BrickletTemperature::CALLBACK_TEMPERATURE_REACHED,
                     'cb_temperatureReached');

// Configure threshold for temperature "greater than 30 °C"
$t->setTemperatureCallbackThreshold('>', 30*100, 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 BrickletTemperature(string $uid, IPConnection $ipcon)

Creates an object with the unique device ID $uid:

<?php   $temperature = new BrickletTemperature('YOUR_DEVICE_UID', $ipcon);   ?>

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

int BrickletTemperature::getTemperature()

Returns the temperature of the sensor. The value has a range of -2500 to 8500 and is given in °C/100, e.g. a value of 4223 means that a temperature of 42.23 °C is measured.

If you want to get the temperature periodically, it is recommended to use the CALLBACK_TEMPERATURE callback and set the period with setTemperatureCallbackPeriod().

Advanced Functions

void BrickletTemperature::setI2CMode(int $mode)

Sets the I2C mode. Possible modes are:

  • 0: Fast (400kHz, default)
  • 1: Slow (100kHz)

If you have problems with obvious outliers in the Temperature Bricklet measurements, they may be caused by EMI issues. In this case it may be helpful to lower the I2C speed.

It is however not recommended to lower the I2C speed in applications where a high throughput needs to be achieved.

The following constants are available for this function:

  • BrickletTemperature::I2C_MODE_FAST = 0
  • BrickletTemperature::I2C_MODE_SLOW = 1

New in version 2.0.1 (Plugin).

int BrickletTemperature::getI2CMode()

Returns the I2C mode as set by setI2CMode().

The following constants are available for this function:

  • BrickletTemperature::I2C_MODE_FAST = 0
  • BrickletTemperature::I2C_MODE_SLOW = 1

New in version 2.0.1 (Plugin).

array BrickletTemperature::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 BrickletTemperature::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 BrickletTemperature::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:

  • BrickletTemperature::FUNCTION_SET_TEMPERATURE_CALLBACK_PERIOD = 2
  • BrickletTemperature::FUNCTION_SET_TEMPERATURE_CALLBACK_THRESHOLD = 4
  • BrickletTemperature::FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BrickletTemperature::FUNCTION_SET_I2C_MODE = 10
void BrickletTemperature::setResponseExpectedAll(bool $response_expected)

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

array BrickletTemperature::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 BrickletTemperature::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 BrickletTemperature::setTemperatureCallbackPeriod(int $period)

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

The CALLBACK_TEMPERATURE callback is only triggered if the temperature has changed since the last triggering.

The default value is 0.

int BrickletTemperature::getTemperatureCallbackPeriod()

Returns the period as set by setTemperatureCallbackPeriod().

void BrickletTemperature::setTemperatureCallbackThreshold(string $option, int $min, int $max)

Sets the thresholds for the CALLBACK_TEMPERATURE_REACHED callback.

The following options are possible:

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

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

The following constants are available for this function:

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

Returns the threshold as set by setTemperatureCallbackThreshold().

The following constants are available for this function:

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

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

void BrickletTemperature::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 BrickletTemperature::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";
}

$temperature->registerCallback(BrickletTemperature::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 BrickletTemperature::CALLBACK_TEMPERATURE
<?php   void callback(int $temperature [, mixed $user_data])   ?>

This callback is triggered periodically with the period that is set by setTemperatureCallbackPeriod(). The parameter is the temperature of the sensor.

The CALLBACK_TEMPERATURE callback is only triggered if the temperature has changed since the last triggering.

int BrickletTemperature::CALLBACK_TEMPERATURE_REACHED
<?php   void callback(int $temperature [, mixed $user_data])   ?>

This callback is triggered when the threshold as set by setTemperatureCallbackThreshold() is reached. The parameter is the temperature of the sensor.

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

Constants

int BrickletTemperature::DEVICE_IDENTIFIER

This constant is used to identify a Temperature 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 BrickletTemperature::DEVICE_DISPLAY_NAME

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