PHP - Rotary Poti Bricklet

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

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletRotaryPoti;

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

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

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

// Get current position
$position = $rp->getPosition();
echo "Position: $position\n"; // Range: -150 to 150

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/BrickletRotaryPoti.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletRotaryPoti;

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

// Callback function for position callback
function cb_position($position)
{
    echo "Position: $position\n"; // Range: -150 to 150
}

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

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

// Register position callback to function cb_position
$rp->registerCallback(BrickletRotaryPoti::CALLBACK_POSITION, 'cb_position');

// Set period for position callback to 0.05s (50ms)
// Note: The position callback is only called every 0.05 seconds
//       if the position has changed since the last call!
$rp->setPositionCallbackPeriod(50);

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 BrickletRotaryPoti(string $uid, IPConnection $ipcon)

Creates an object with the unique device ID $uid:

<?php   $rotary_poti = new BrickletRotaryPoti('YOUR_DEVICE_UID', $ipcon);   ?>

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

int BrickletRotaryPoti::getPosition()

Returns the position of the rotary potentiometer. The value is in degree and between -150° (turned left) and 150° (turned right).

If you want to get the position periodically, it is recommended to use the CALLBACK_POSITION callback and set the period with setPositionCallbackPeriod().

Advanced Functions

int BrickletRotaryPoti::getAnalogValue()

Returns the value as read by a 12-bit analog-to-digital converter. The value is between 0 and 4095.

Note

The value returned by getPosition() is averaged over several samples to yield less noise, while getAnalogValue() gives back raw unfiltered analog values. The only reason to use getAnalogValue() is, if you need the full resolution of the analog-to-digital converter.

If you want the analog value periodically, it is recommended to use the CALLBACK_ANALOG_VALUE callback and set the period with setAnalogValueCallbackPeriod().

array BrickletRotaryPoti::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 BrickletRotaryPoti::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 BrickletRotaryPoti::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:

  • BrickletRotaryPoti::FUNCTION_SET_POSITION_CALLBACK_PERIOD = 3
  • BrickletRotaryPoti::FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • BrickletRotaryPoti::FUNCTION_SET_POSITION_CALLBACK_THRESHOLD = 7
  • BrickletRotaryPoti::FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • BrickletRotaryPoti::FUNCTION_SET_DEBOUNCE_PERIOD = 11
void BrickletRotaryPoti::setResponseExpectedAll(bool $response_expected)

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

array BrickletRotaryPoti::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 BrickletRotaryPoti::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 BrickletRotaryPoti::setPositionCallbackPeriod(int $period)

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

The CALLBACK_POSITION callback is only triggered if the position has changed since the last triggering.

The default value is 0.

int BrickletRotaryPoti::getPositionCallbackPeriod()

Returns the period as set by setPositionCallbackPeriod().

void BrickletRotaryPoti::setAnalogValueCallbackPeriod(int $period)

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

The CALLBACK_ANALOG_VALUE callback is only triggered if the analog value has changed since the last triggering.

The default value is 0.

int BrickletRotaryPoti::getAnalogValueCallbackPeriod()

Returns the period as set by setAnalogValueCallbackPeriod().

void BrickletRotaryPoti::setPositionCallbackThreshold(string $option, int $min, int $max)

Sets the thresholds for the CALLBACK_POSITION_REACHED callback.

The following options are possible:

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

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

The following constants are available for this function:

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

Returns the threshold as set by setPositionCallbackThreshold().

The following constants are available for this function:

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

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

void BrickletRotaryPoti::setAnalogValueCallbackThreshold(string $option, int $min, int $max)

Sets the thresholds for the CALLBACK_ANALOG_VALUE_REACHED callback.

The following options are possible:

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

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

Returns the threshold as set by setAnalogValueCallbackThreshold().

The following constants are available for this function:

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

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

void BrickletRotaryPoti::setDebouncePeriod(int $debounce)

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

int BrickletRotaryPoti::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";
}

$rotary_poti->registerCallback(BrickletRotaryPoti::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 BrickletRotaryPoti::CALLBACK_POSITION
<?php   void callback(int $position [, mixed $user_data])   ?>

This callback is triggered periodically with the period that is set by setPositionCallbackPeriod(). The parameter is the position of the rotary potentiometer.

The CALLBACK_POSITION callback is only triggered if the position has changed since the last triggering.

int BrickletRotaryPoti::CALLBACK_ANALOG_VALUE
<?php   void callback(int $value [, mixed $user_data])   ?>

This callback is triggered periodically with the period that is set by setAnalogValueCallbackPeriod(). The parameter is the analog value of the rotary potentiometer.

The CALLBACK_ANALOG_VALUE callback is only triggered if the position has changed since the last triggering.

int BrickletRotaryPoti::CALLBACK_POSITION_REACHED
<?php   void callback(int $position [, mixed $user_data])   ?>

This callback is triggered when the threshold as set by setPositionCallbackThreshold() is reached. The parameter is the position of the rotary potentiometer.

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

int BrickletRotaryPoti::CALLBACK_ANALOG_VALUE_REACHED
<?php   void callback(int $value [, mixed $user_data])   ?>

This callback is triggered when the threshold as set by setAnalogValueCallbackThreshold() is reached. The parameter is the analog value of the rotary potentiometer.

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

Constants

int BrickletRotaryPoti::DEVICE_IDENTIFIER

This constant is used to identify a Rotary Poti 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 BrickletRotaryPoti::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Rotary Poti Bricklet.