This is the description of the JavaScript API bindings for the Rotary Encoder Bricklet. General information and technical specifications for the Rotary Encoder Bricklet are summarized in its hardware description.
An installation guide for the JavaScript API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 | var Tinkerforge = require('tinkerforge');
var HOST = 'localhost';
var PORT = 4223;
var UID = 'utz'; // Change to your UID
var ipcon = new Tinkerforge.IPConnection(); // Create IP connection
var encoder = new Tinkerforge.BrickletRotaryEncoder(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 count of encoder without reset
encoder.getCount(false,
function(count) {
console.log('Count: '+count);
},
function(error) {
console.log('Error: '+error);
}
);
}
);
console.log("Press any key to exit ...");
process.stdin.on('data',
function(data) {
ipcon.disconnect();
process.exit(0);
}
);
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 | var Tinkerforge = require('tinkerforge');
var HOST = 'localhost';
var PORT = 4223;
var UID = 'utz'; // Change to your UID
var ipcon = new Tinkerforge.IPConnection(); // Create IP connection
var encoder = new Tinkerforge.BrickletRotaryEncoder(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 count callback to 0.05s (50ms)
// Note: The count callback is only called every 50ms if the
// count has changed since the last call!
encoder.setCountCallbackPeriod(50);
}
);
// Register count callback
encoder.on(Tinkerforge.BrickletRotaryEncoder.CALLBACK_COUNT,
// Callback function for count callback
function(count) {
console.log('Count: '+count);
}
);
console.log("Press any key to exit ...");
process.stdin.on('data',
function(data) {
ipcon.disconnect();
process.exit(0);
}
);
|
Download (ExampleSimple.html), Test (ExampleSimple.html)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 | <!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 Encoder 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 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 encoder = new Tinkerforge.BrickletRotaryEncoder(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 count of encoder without reset
encoder.getCount(false,
function(count) {
textArea.value += 'Count: '+count+'\n';
},
function(error) {
textArea.value += 'Error: '+error+'\n';
}
);
}
);
}
</script>
</body>
</html>
|
Download (ExampleCallback.html), Test (ExampleCallback.html)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 | <!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 Encoder 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 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 encoder = new Tinkerforge.BrickletRotaryEncoder(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 count callback to 0.05s (50ms)
// Note: The count callback is only called every 50ms if the
// count has changed since the last call!
encoder.setCountCallbackPeriod(50);
}
);
// Register count callback
encoder.on(Tinkerforge.BrickletRotaryEncoder.CALLBACK_COUNT,
// Callback function for count callback
function(count) {
textArea.value += 'Count: '+count+'\n';
textArea.value += '\n';
textArea.scrollTop = textArea.scrollHeight;
}
);
}
</script>
</body>
</html>
|
Generally, every method of the JavaScript bindings can take two optional parameters, returnCallback and errorCallback. These are two user defined callback functions. The returnCallback is called with the return values as parameters, if the method returns something. The errorCallback is called with an error code in case of an error. The error code can be one of the following values:
The namespace for the JavaScript bindings is Tinkerforge.*.
Parameters: |
|
---|
Creates an object with the unique device ID uid:
var rotaryEncoder = new BrickletRotaryEncoder("YOUR_DEVICE_UID", ipcon);
This object can then be used after the IP Connection is connected (see examples above).
Parameters: |
|
---|---|
Callback: |
|
Returns the current count of the encoder. If you set reset to true, the count is set back to 0 directly after the current count is read.
The encoder has 24 steps per rotation
Turning the encoder to the left decrements the counter, so a negative count is possible.
Callback: |
|
---|
Returns true if the button is pressed and false otherwise.
It is recommended to use the CALLBACK_PRESSED and CALLBACK_RELEASED callbacks to handle the button.
Return type: | [int, int, int] |
---|
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.
Parameters: |
|
---|---|
Return 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 send and errors are silently ignored, because they cannot be detected.
See setResponseExpected() for the list of function ID constants available for this function.
Parameters: |
|
---|
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 and callbacks it is always disabled.
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:
Parameters: |
|
---|
Changes the response expected flag for all setter and callback configuration functions of this device at once.
Callback: |
|
---|
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.
Parameters: |
|
---|
Registers a callback with ID id to the function callback. The available IDs with corresponding function signatures are listed below.
Parameters: |
|
---|---|
Callback: | undefined |
Sets the period in ms with which the CALLBACK_COUNT callback is triggered periodically. A value of 0 turns the callback off.
CALLBACK_COUNT is only triggered if the count has changed since the last triggering.
The default value is 0.
Callback: |
|
---|
Returns the period as set by setCountCallbackPeriod().
Parameters: |
|
---|---|
Callback: | undefined |
Sets the thresholds for the CALLBACK_COUNT_REACHED callback.
The following options are possible:
Option | Description |
---|---|
'x' | Callback is turned off |
'o' | Callback is triggered when the count is outside the min and max values |
'i' | Callback is triggered when the count is inside the min and max values |
'<' | Callback is triggered when the count is smaller than the min value (max is ignored) |
'>' | Callback is triggered when the count is greater than the min value (max is ignored) |
The default value is ('x', 0, 0).
The following constants are available for this function:
Callback: |
|
---|
Returns the threshold as set by setCountCallbackThreshold().
The following constants are available for this function:
Parameters: |
|
---|---|
Callback: | undefined |
Sets the period in ms with which the threshold callback
is triggered, if the thresholds
keeps being reached.
The default value is 100.
Callback: |
|
---|
Returns the debounce period as set by setDebouncePeriod().
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:
rotaryEncoder.on(BrickletRotaryEncoder.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.
Parameters: |
|
---|
This callback is triggered periodically with the period that is set by setCountCallbackPeriod(). The parameter is the count of the encoder.
CALLBACK_COUNT is only triggered if the count has changed since the last triggering.
Parameters: |
|
---|
This callback is triggered when the threshold as set by setCountCallbackThreshold() is reached. The parameter is the count of the encoder.
If the threshold keeps being reached, the callback is triggered periodically with the period as set by setDebouncePeriod().
This callback is triggered when the button is pressed.
This callback is triggered when the button is released.
This constant is used to identify a Rotary Encoder Bricklet.
The getIdentity() function and the CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.