Software / API Bindings / JavaScript / API Reference and Examples / Bricklets / Rotary Poti Bricklet

JavaScript - Rotary Poti Bricklet¶

This is the description of the JavaScript 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 JavaScript API bindings is part of their general description.

Examples¶

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

Simple (Node.js)¶

Download (ExampleSimple.js)

var Tinkerforge = require('tinkerforge');

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

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

ipcon.connect(HOST, PORT,
    function (error) {
        console.log('Error: ' + error);
    }
); // Connect to brickd
// Don't use device before ipcon is connected

ipcon.on(Tinkerforge.IPConnection.CALLBACK_CONNECTED,
    function (connectReason) {
        // Get current position
        rp.getPosition(
            function (position) {
                console.log('Position: ' + position); // Range: -150 to 150
            },
            function (error) {
                console.log('Error: ' + error);
            }
        );
    }
);

console.log('Press key to exit');
process.stdin.on('data',
    function (data) {
        ipcon.disconnect();
        process.exit(0);
    }
);

Callback (Node.js)¶

Download (ExampleCallback.js)

var Tinkerforge = require('tinkerforge');

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

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

ipcon.connect(HOST, PORT,
    function (error) {
        console.log('Error: ' + error);
    }
); // Connect to brickd
// Don't use device before ipcon is connected

ipcon.on(Tinkerforge.IPConnection.CALLBACK_CONNECTED,
    function (connectReason) {
        // 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);
    }
);

// Register position callback
rp.on(Tinkerforge.BrickletRotaryPoti.CALLBACK_POSITION,
    // Callback function for position callback
    function (position) {
        console.log('Position: ' + position); // Range: -150 to 150
    }
);

console.log('Press key to exit');
process.stdin.on('data',
    function (data) {
        ipcon.disconnect();
        process.exit(0);
    }
);

Simple (HTML)¶

Download (ExampleSimple.html), Test (ExampleSimple.html)

<!DOCTYPE html>
<html>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <head>
        <title>Tinkerforge | JavaScript Example</title>
    </head>
    <body>
        <div style="text-align:center;">
            <h1>Rotary Poti Bricklet Simple Example</h1>
            <p>
                <input value="localhost" id="host" type="text" size="20">:
                <input value="4280" id="port" type="text" size="5">,
                <input value="uid" id="uid" type="text" size="5">
                <input value="Start Example" id="start" type="button" onclick="startExample();">
            </p>
            <p>
                <textarea readonly id="text" cols="80" rows="24" style="resize:none;"
                          >Press "Start Example" to begin ...</textarea>
            </p>
        </div>
        <script src="./Tinkerforge.js" type='text/javascript'></script>
        <script type='text/javascript'>
            var ipcon;
            var textArea = document.getElementById("text");
            function startExample() {
                textArea.value = "";
                var HOST = document.getElementById("host").value;
                var PORT = parseInt(document.getElementById("port").value);
                var UID = document.getElementById("uid").value;
                if(ipcon !== undefined) {
                    ipcon.disconnect();
                }
                ipcon = new Tinkerforge.IPConnection(); // Create IP connection
                var rp = new Tinkerforge.BrickletRotaryPoti(UID, ipcon); // Create device object
                ipcon.connect(HOST, PORT,
                    function(error) {
                        textArea.value += 'Error: ' + error + '\n';
                    }
                ); // Connect to brickd
                // Don't use device before ipcon is connected

                ipcon.on(Tinkerforge.IPConnection.CALLBACK_CONNECTED,
                    function (connectReason) {
                        // Get current position
                        rp.getPosition(
                            function (position) {
                                textArea.value += 'Position: ' + position + '\n'; // Range: -150 to 150
                            },
                            function (error) {
                                textArea.value += 'Error: ' + error + '\n';
                            }
                        );
                    }
                );
            }
        </script>
    </body>
</html>

Callback (HTML)¶

Download (ExampleCallback.html), Test (ExampleCallback.html)

<!DOCTYPE html>
<html>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <head>
        <title>Tinkerforge | JavaScript Example</title>
    </head>
    <body>
        <div style="text-align:center;">
            <h1>Rotary Poti Bricklet Callback Example</h1>
            <p>
                <input value="localhost" id="host" type="text" size="20">:
                <input value="4280" id="port" type="text" size="5">,
                <input value="uid" id="uid" type="text" size="5">
                <input value="Start Example" id="start" type="button" onclick="startExample();">
            </p>
            <p>
                <textarea readonly id="text" cols="80" rows="24" style="resize:none;"
                          >Press "Start Example" to begin ...</textarea>
            </p>
        </div>
        <script src="./Tinkerforge.js" type='text/javascript'></script>
        <script type='text/javascript'>
            var ipcon;
            var textArea = document.getElementById("text");
            function startExample() {
                textArea.value = "";
                var HOST = document.getElementById("host").value;
                var PORT = parseInt(document.getElementById("port").value);
                var UID = document.getElementById("uid").value;
                if(ipcon !== undefined) {
                    ipcon.disconnect();
                }
                ipcon = new Tinkerforge.IPConnection(); // Create IP connection
                var rp = new Tinkerforge.BrickletRotaryPoti(UID, ipcon); // Create device object
                ipcon.connect(HOST, PORT,
                    function(error) {
                        textArea.value += 'Error: ' + error + '\n';
                    }
                ); // Connect to brickd
                // Don't use device before ipcon is connected

                ipcon.on(Tinkerforge.IPConnection.CALLBACK_CONNECTED,
                    function (connectReason) {
                        // 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);
                    }
                );

                // Register position callback
                rp.on(Tinkerforge.BrickletRotaryPoti.CALLBACK_POSITION,
                    // Callback function for position callback
                    function (position) {
                        textArea.value += 'Position: ' + position + '\n'; // Range: -150 to 150
                        textArea.scrollTop = textArea.scrollHeight;
                    }
                );
            }
        </script>
    </body>
</html>

API¶

Generally, every function of the JavaScript bindings can take two optional parameters, returnCallback and errorCallback. These are two user defined callback functions. The returnCallback function is called with the results as arguments, if the function returns its results asynchronously. The errorCallback is called with an error code in case of an error. The error code can be one of the following values:

IPConnection.ERROR_ALREADY_CONNECTED = 11
IPConnection.ERROR_NOT_CONNECTED = 12
IPConnection.ERROR_CONNECT_FAILED = 13
IPConnection.ERROR_INVALID_FUNCTION_ID = 21
IPConnection.ERROR_TIMEOUT = 31
IPConnection.ERROR_INVALID_PARAMETER = 41
IPConnection.ERROR_FUNCTION_NOT_SUPPORTED = 42
IPConnection.ERROR_UNKNOWN_ERROR = 43
IPConnection.ERROR_STREAM_OUT_OF_SYNC = 51
IPConnection.ERROR_NON_ASCII_CHAR_IN_SECRET = 71
IPConnection.ERROR_WRONG_DEVICE_TYPE = 81
IPConnection.ERROR_DEVICE_REPLACED = 82
IPConnection.ERROR_WRONG_RESPONSE_LENGTH = 83
IPConnection.ERROR_INT64_NOT_SUPPORTED = 91

The namespace for the JavaScript bindings is Tinkerforge.*.

Basic Functions¶

new BrickletRotaryPoti(uid, ipcon)¶

Parameters:	uid – Type: string ipcon – Type: IPConnection
Returns:	rotaryPoti – Type: BrickletRotaryPoti

Creates an object with the unique device ID uid:

var rotaryPoti = new BrickletRotaryPoti("YOUR_DEVICE_UID", ipcon);

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

BrickletRotaryPoti.getPosition([returnCallback][, errorCallback])¶

Callback Parameters:	position – Type: int, Unit: 1 °, Range: [-150 to 150]
Returns:	undefined

Returns the position of the rotary potentiometer. The value is 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¶

BrickletRotaryPoti.getAnalogValue([returnCallback][, errorCallback])¶

Callback Parameters:	value – Type: int, Range: [0 to 2¹²]
Returns:	undefined

Returns the value as read by a 12-bit analog-to-digital converter.

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().

BrickletRotaryPoti.getIdentity([returnCallback][, errorCallback])¶

Callback Parameters:

Callback Parameters:	uid – Type: string, Length: up to 8 connectedUid – Type: string, Length: up to 8 position – Type: char, Range: ['a' to 'h', 'z'] hardwareVersion – 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] firmwareVersion – 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] deviceIdentifier – Type: int, Range: [0 to 2¹⁶ - 1]
Returns:	undefined

uid – Type: string, Length: up to 8
connectedUid – Type: string, Length: up to 8
position – Type: char, Range: ['a' to 'h', 'z']
hardwareVersion – 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]

firmwareVersion – 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]

deviceIdentifier – Type: int, Range: [0 to 2¹⁶ - 1]

Returns:

undefined

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¶

BrickletRotaryPoti.on(callback_id, function[, errorCallback])¶

Parameters:	callback_id – Type: int function – Type: function
Returns:	undefined

Registers the given function with the given callback_id.

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

BrickletRotaryPoti.setPositionCallbackPeriod(period[, returnCallback][, errorCallback])¶

Parameters:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Callback Parameters:	undefined
Returns:	undefined

Sets the period 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.

BrickletRotaryPoti.getPositionCallbackPeriod([returnCallback][, errorCallback])¶

Callback Parameters:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Returns:	undefined

Returns the period as set by setPositionCallbackPeriod().

BrickletRotaryPoti.setAnalogValueCallbackPeriod(period[, returnCallback][, errorCallback])¶

Parameters:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Callback Parameters:	undefined
Returns:	undefined

Sets the period 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.

BrickletRotaryPoti.getAnalogValueCallbackPeriod([returnCallback][, errorCallback])¶

Callback Parameters:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Returns:	undefined

Returns the period as set by setAnalogValueCallbackPeriod().

BrickletRotaryPoti.setPositionCallbackThreshold(option, min, max[, returnCallback][, errorCallback])¶

Parameters:	option – Type: char, Range: See constants, Default: 'x' min – Type: int, Unit: 1 °, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0 max – Type: int, Unit: 1 °, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0
Callback Parameters:	undefined
Returns:	undefined

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 following constants are available for this function:

For option:

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

BrickletRotaryPoti.getPositionCallbackThreshold([returnCallback][, errorCallback])¶

Callback Parameters:	option – Type: char, Range: See constants, Default: 'x' min – Type: int, Unit: 1 °, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0 max – Type: int, Unit: 1 °, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0
Returns:	undefined

Returns the threshold as set by setPositionCallbackThreshold().

The following constants are available for this function:

For option:

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

BrickletRotaryPoti.setAnalogValueCallbackThreshold(option, min, max[, returnCallback][, errorCallback])¶

Parameters:	option – Type: char, Range: See constants, Default: 'x' min – Type: int, Unit: 1 °, Range: [0 to 2¹⁶ - 1], Default: 0 max – Type: int, Unit: 1 °, Range: [0 to 2¹⁶ - 1], Default: 0
Callback Parameters:	undefined
Returns:	undefined

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 following constants are available for this function:

For option:

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

BrickletRotaryPoti.getAnalogValueCallbackThreshold([returnCallback][, errorCallback])¶

Callback Parameters:	option – Type: char, Range: See constants, Default: 'x' min – Type: int, Unit: 1 °, Range: [0 to 2¹⁶ - 1], Default: 0 max – Type: int, Unit: 1 °, Range: [0 to 2¹⁶ - 1], Default: 0
Returns:	undefined

Returns the threshold as set by setAnalogValueCallbackThreshold().

The following constants are available for this function:

For option:

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

BrickletRotaryPoti.setDebouncePeriod(debounce[, returnCallback][, errorCallback])¶

Parameters:	debounce – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100
Callback Parameters:	undefined
Returns:	undefined

Sets the period with which the threshold callbacks

CALLBACK_POSITION_REACHED,
CALLBACK_ANALOG_VALUE_REACHED

are triggered, if the thresholds

setPositionCallbackThreshold(),
setAnalogValueCallbackThreshold()

keep being reached.

BrickletRotaryPoti.getDebouncePeriod([returnCallback][, errorCallback])¶

Callback Parameters:	debounce – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100
Returns:	undefined

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 on() function of the device object. The first parameter is the callback ID and the second parameter the callback function:

rotaryPoti.on(BrickletRotaryPoti.CALLBACK_EXAMPLE,
    function (param) {
        console.log(param);
    }
);

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.

BrickletRotaryPoti.CALLBACK_POSITION¶

Callback Parameters:	position – Type: int, Unit: 1 °, Range: [-150 to 150]

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.

BrickletRotaryPoti.CALLBACK_ANALOG_VALUE¶

Callback Parameters:	value – Type: int, Range: [0 to 2¹²]

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.

BrickletRotaryPoti.CALLBACK_POSITION_REACHED¶

Callback Parameters:	position – Type: int, Unit: 1 °, Range: [-150 to 150]

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().

BrickletRotaryPoti.CALLBACK_ANALOG_VALUE_REACHED¶

Callback Parameters:	value – Type: int, Range: [0 to 2¹²]

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().

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.

BrickletRotaryPoti.getAPIVersion()¶

Returns:	apiVersion – 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.

BrickletRotaryPoti.getResponseExpected(functionId[, errorCallback])¶

Parameters:	functionId – Type: int, Range: See constants
Returns:	responseExpected – Type: boolean

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:

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

BrickletRotaryPoti.setResponseExpected(functionId, responseExpected[, errorCallback])¶

Parameters:	functionId – Type: int, Range: See constants responseExpected – Type: boolean
Returns:	undefined

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:

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

BrickletRotaryPoti.setResponseExpectedAll(responseExpected)¶

Parameters:	responseExpected – Type: boolean
Returns:	undefined

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

Constants¶

BrickletRotaryPoti.DEVICE_IDENTIFIER¶

This constant is used to identify a Rotary Poti Bricklet.

The getIdentity() 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.

BrickletRotaryPoti.DEVICE_DISPLAY_NAME¶: This constant represents the human readable name of a Rotary Poti Bricklet.