Mathematica - Rotary Encoder Bricklet

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

Examples

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

Simple

Download (ExampleSimple.nb)

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Needs["NETLink`"]
LoadNETAssembly["Tinkerforge",NotebookDirectory[]<>"../../.."]

host="localhost"
port=4223
uid="XYZ"(*Change XYZ to the UID of your Rotary Encoder Bricklet*)

(*Create IPConnection and device object*)
ipcon=NETNew["Tinkerforge.IPConnection"]
re=NETNew["Tinkerforge.BrickletRotaryEncoder",uid,ipcon]
ipcon@Connect[host,port]

(*Get current count without reset*)
Print["Count: "<>ToString[re@GetCount[False]]]

(*Clean up*)
ipcon@Disconnect[]
ReleaseNETObject[re]
ReleaseNETObject[ipcon]

Callback

Download (ExampleCallback.nb)

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Needs["NETLink`"]
LoadNETAssembly["Tinkerforge",NotebookDirectory[]<>"../../.."]

host="localhost"
port=4223
uid="XYZ"(*Change XYZ to the UID of your Rotary Encoder Bricklet*)

(*Create IPConnection and device object*)
ipcon=NETNew["Tinkerforge.IPConnection"]
re=NETNew["Tinkerforge.BrickletRotaryEncoder",uid,ipcon]
ipcon@Connect[host,port]

(*Callback function for count callback*)
CountCB[sender_,count_]:=
 Print["Count: "<>ToString[count]]
AddEventHandler[re@CountCallback,CountCB]

(*Set period for count callback to 0.05s (50ms)*)
(*Note: The count callback is only called every 0.05 seconds*)
(*if the count has changed since the last call!*)
re@SetCountCallbackPeriod[50]

Input["Click OK to exit"]

(*Clean up*)
ipcon@Disconnect[]
ReleaseNETObject[re]
ReleaseNETObject[ipcon]

API

Generally, every function of the Mathematica bindings that returns a value can throw a Tinkerforge.TimeoutException. This exception gets thrown if the device did not respond. If a cable based connection is used, it is unlikely that this exception gets thrown (assuming nobody plugs the device out). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.

Since .NET/Link does not support multiple return values directly, we use the out keyword to return multiple values from a function. For further information about the out keyword in .NET/Link see the corresponding Mathematica .NET/Link documentation.

The namespace for all Brick/Bricklet bindings and the IPConnection is Tinkerforge.*.

Basic Functions

BrickletRotaryEncoder[uid, ipcon] → rotaryEncoder
Parameters:
  • uid – Type: String
  • ipcon – Type: NETObject[IPConnection]
Returns:
  • rotaryEncoder – Type: NETObject[BrickletRotaryEncoder]

Creates an object with the unique device ID uid:

rotaryEncoder=NETNew["Tinkerforge.BrickletRotaryEncoder","YOUR_DEVICE_UID",ipcon]

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

The .NET runtime has built-in garbage collection that frees objects that are no longer in use by a program. But because Mathematica can not automatically tell when a Mathematica "program" doesn't use a .NET object anymore, this has to be done by the program. For this the ReleaseNETObject[] function is used in the examples.

For further information about object management in .NET/Link see the corresponding Mathematica .NET/Link documentation.

BrickletRotaryEncoder@GetCount[reset] → count
Parameters:
  • reset – Type: True/False
Returns:
  • count – Type: Integer, Range: [-231 to 231 - 1]

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.

BrickletRotaryEncoder@IsPressed[] → pressed
Returns:
  • pressed – Type: True/False

Returns true if the button is pressed and false otherwise.

It is recommended to use the PressedCallback and ReleasedCallback callbacks to handle the button.

Advanced Functions

BrickletRotaryEncoder@GetIdentity[out uid, out connectedUid, out position, out {hardwareVersion1, hardwareVersion2, hardwareVersion3}, out {firmwareVersion1, firmwareVersion2, firmwareVersion3}, out deviceIdentifier] → Null
Output Parameters:
  • uid – Type: String, Length: up to 8
  • connectedUid – Type: String, Length: up to 8
  • position – Type: Integer, Range: [ToCharacterCode["a"][[0]] to ToCharacterCode["h"][[0]], ToCharacterCode["i"][[0]], ToCharacterCode["z"][[0]]]
  • hardwareVersioni – Type: Integer
    • 1: major – Type: Integer, Range: [0 to 255]
    • 2: minor – Type: Integer, Range: [0 to 255]
    • 3: revision – Type: Integer, Range: [0 to 255]
  • firmwareVersioni – Type: Integer
    • 1: major – Type: Integer, Range: [0 to 255]
    • 2: minor – Type: Integer, Range: [0 to 255]
    • 3: revision – Type: Integer, Range: [0 to 255]
  • deviceIdentifier – Type: Integer, Range: [0 to 216 - 1]

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). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as 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

BrickletRotaryEncoder@SetCountCallbackPeriod[period] → Null
Parameters:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

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

The CountCallback callback is only triggered if the count has changed since the last triggering.

BrickletRotaryEncoder@GetCountCallbackPeriod[] → period
Returns:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by SetCountCallbackPeriod[].

BrickletRotaryEncoder@SetCountCallbackThreshold[option, min, max] → Null
Parameters:
  • option – Type: Integer, Range: See constants, Default: ToCharacterCode["x"][[0]]
  • min – Type: Integer, Range: [-231 to 231 - 1], Default: 0
  • max – Type: Integer, Range: [-231 to 231 - 1], Default: 0

Sets the thresholds for the CountReachedCallback 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 following constants are available for this function:

For option:

  • BrickletRotaryEncoder`THRESHOLDUOPTIONUOFF = ToCharacterCode["x"][[0]]
  • BrickletRotaryEncoder`THRESHOLDUOPTIONUOUTSIDE = ToCharacterCode["o"][[0]]
  • BrickletRotaryEncoder`THRESHOLDUOPTIONUINSIDE = ToCharacterCode["i"][[0]]
  • BrickletRotaryEncoder`THRESHOLDUOPTIONUSMALLER = ToCharacterCode["<"][[0]]
  • BrickletRotaryEncoder`THRESHOLDUOPTIONUGREATER = ToCharacterCode[">"][[0]]
BrickletRotaryEncoder@GetCountCallbackThreshold[out option, out min, out max] → Null
Output Parameters:
  • option – Type: Integer, Range: See constants, Default: ToCharacterCode["x"][[0]]
  • min – Type: Integer, Range: [-231 to 231 - 1], Default: 0
  • max – Type: Integer, Range: [-231 to 231 - 1], Default: 0

Returns the threshold as set by SetCountCallbackThreshold[].

The following constants are available for this function:

For option:

  • BrickletRotaryEncoder`THRESHOLDUOPTIONUOFF = ToCharacterCode["x"][[0]]
  • BrickletRotaryEncoder`THRESHOLDUOPTIONUOUTSIDE = ToCharacterCode["o"][[0]]
  • BrickletRotaryEncoder`THRESHOLDUOPTIONUINSIDE = ToCharacterCode["i"][[0]]
  • BrickletRotaryEncoder`THRESHOLDUOPTIONUSMALLER = ToCharacterCode["<"][[0]]
  • BrickletRotaryEncoder`THRESHOLDUOPTIONUGREATER = ToCharacterCode[">"][[0]]
BrickletRotaryEncoder@SetDebouncePeriod[debounce] → Null
Parameters:
  • debounce – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Sets the period with which the threshold callback

is triggered, if the thresholds

keeps being reached.

BrickletRotaryEncoder@GetDebouncePeriod[] → debounce
Returns:
  • debounce – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

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 by assigning a function to a callback property of the device object:

MyCallback[sender_,value_]:=Print["Value: "<>ToString[value]]

AddEventHandler[rotaryEncoder@ExampleCallback,MyCallback]

For further information about event handling using .NET/Link see the corresponding Mathematica .NET/Link documentation.

The available callback property and their 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.

event BrickletRotaryEncoder@CountCallback[sender, count]
Callback Parameters:
  • sender – Type: NETObject[BrickletRotaryEncoder]
  • count – Type: Integer, Range: [-231 to 231 - 1]

This callback is triggered periodically with the period that is set by SetCountCallbackPeriod[]. The parameter is the count of the encoder.

The CountCallback callback is only triggered if the count has changed since the last triggering.

event BrickletRotaryEncoder@CountReachedCallback[sender, count]
Callback Parameters:
  • sender – Type: NETObject[BrickletRotaryEncoder]
  • count – Type: Integer, Range: [-231 to 231 - 1]

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[].

event BrickletRotaryEncoder@PressedCallback[sender]
Callback Parameters:
  • sender – Type: NETObject[BrickletRotaryEncoder]

This callback is triggered when the button is pressed.

event BrickletRotaryEncoder@ReleasedCallback[sender]
Callback Parameters:
  • sender – Type: NETObject[BrickletRotaryEncoder]

This callback is triggered when the button is released.

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.

BrickletRotaryEncoder@GetAPIVersion[] → {apiVersion1, apiVersion2, apiVersion3}
Output Parameters:
  • apiVersioni – Type: Integer
    • 1: major – Type: Integer, Range: [0 to 255]
    • 2: minor – Type: Integer, Range: [0 to 255]
    • 3: revision – Type: Integer, 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.

BrickletRotaryEncoder@GetResponseExpected[functionId] → responseExpected
Parameters:
  • functionId – Type: Integer, Range: See constants
Returns:
  • responseExpected – Type: True/False

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 functionId:

  • BrickletRotaryEncoder`FUNCTIONUSETUCOUNTUCALLBACKUPERIOD = 2
  • BrickletRotaryEncoder`FUNCTIONUSETUCOUNTUCALLBACKUTHRESHOLD = 4
  • BrickletRotaryEncoder`FUNCTIONUSETUDEBOUNCEUPERIOD = 6
BrickletRotaryEncoder@SetResponseExpected[functionId, responseExpected] → Null
Parameters:
  • functionId – Type: Integer, Range: See constants
  • responseExpected – Type: True/False

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

The following constants are available for this function:

For functionId:

  • BrickletRotaryEncoder`FUNCTIONUSETUCOUNTUCALLBACKUPERIOD = 2
  • BrickletRotaryEncoder`FUNCTIONUSETUCOUNTUCALLBACKUTHRESHOLD = 4
  • BrickletRotaryEncoder`FUNCTIONUSETUDEBOUNCEUPERIOD = 6
BrickletRotaryEncoder@SetResponseExpectedAll[responseExpected] → Null
Parameters:
  • responseExpected – Type: True/False

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

Constants

BrickletRotaryEncoder`DEVICEUIDENTIFIER

This constant is used to identify a Rotary Encoder Bricklet.

The GetIdentity[] function and the IPConnection@EnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

BrickletRotaryEncoder`DEVICEDISPLAYNAME

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