Mathematica - Joystick Bricklet

This is the description of the Mathematica API bindings for the Joystick Bricklet. General information and technical specifications for the Joystick 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 Joystick Bricklet*)

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

(*Get current position*)
x=0;y=0
j@GetPosition[x,y]

Print["Position [X]: "<>ToString[x]]
Print["Position [Y]: "<>ToString[y]]

(*Clean up*)
ipcon@Disconnect[]
ReleaseNETObject[j]
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 Joystick Bricklet*)

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

(*Callback function for pressed callback*)
PressedCB[sender_]:=
 Print["Pressed"]
AddEventHandler[j@PressedCallback,PressedCB]

(*Callback function for released callback*)
ReleasedCB[sender_]:=
 Print["Released"]
AddEventHandler[j@ReleasedCallback,ReleasedCB]

Input["Click OK to exit"]

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

Find Borders

Download (ExampleFindBorders.nb)

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

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

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

(*Get threshold callbacks with a debounce time of 0.2 seconds (200ms)*)
j@SetDebouncePeriod[200]

(*Callback function for position reached callback*)
PositionReachedCB[sender_,x_,y_]:=
 Module[{},
  If[y==100,Print["Top"]];
  If[y==-100,Print["Bottom"]];
  If[x==100,Print["Right"]];
  If[x==-100,Print["Left"]];
 ]

AddEventHandler[j@PositionReachedCallback,PositionReachedCB]

(*Configure threshold for position "outside of -99, -99 to 99, 99"*)
option=Tinkerforge`BrickletJoystick`THRESHOLDUOPTIONUOUTSIDE
j@SetPositionCallbackThreshold[option,-99,99,-99,99]

Input["Click OK to exit"]

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

BrickletJoystick[uid, ipcon] → joystick
Parameters:
  • uid – Type: String
  • ipcon – Type: NETObject[IPConnection]
Returns:
  • joystick – Type: NETObject[BrickletJoystick]

Creates an object with the unique device ID uid:

joystick=NETNew["Tinkerforge.BrickletJoystick","YOUR_DEVICE_UID",ipcon]

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

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.

BrickletJoystick@GetPosition[out x, out y] → Null
Output Parameters:
  • x – Type: Integer, Range: [-100 to 100]
  • y – Type: Integer, Range: [-100 to 100]

Returns the position of the joystick. The middle position of the joystick is x=0, y=0. The returned values are averaged and calibrated (see Calibrate[]).

If you want to get the position periodically, it is recommended to use the PositionCallback callback and set the period with SetPositionCallbackPeriod[].

BrickletJoystick@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

BrickletJoystick@GetAnalogValue[out x, out y] → Null
Output Parameters:
  • x – Type: Integer, Range: [0 to 4095]
  • y – Type: Integer, Range: [0 to 4095]

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

Note

The values returned by GetPosition[] are 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 values periodically, it is recommended to use the AnalogValueCallback callback and set the period with SetAnalogValueCallbackPeriod[].

BrickletJoystick@Calibrate[] → Null

Calibrates the middle position of the joystick. If your Joystick Bricklet does not return x=0 and y=0 in the middle position, call this function while the joystick is standing still in the middle position.

The resulting calibration will be saved on the EEPROM of the Joystick Bricklet, thus you only have to calibrate it once.

BrickletJoystick@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

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

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

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

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

Returns the period as set by SetPositionCallbackPeriod[].

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

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

The AnalogValueCallback callback is only triggered if the analog values have changed since the last triggering.

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

Returns the period as set by SetAnalogValueCallbackPeriod[].

BrickletJoystick@SetPositionCallbackThreshold[option, minX, maxX, minY, maxY] → Null
Parameters:
  • option – Type: Integer, Range: See constants, Default: ToCharacterCode["x"][[0]]
  • minX – Type: Integer, Range: [-215 to 215 - 1], Default: 0
  • maxX – Type: Integer, Range: [-215 to 215 - 1], Default: 0
  • minY – Type: Integer, Range: [-215 to 215 - 1], Default: 0
  • maxY – Type: Integer, Range: [-215 to 215 - 1], Default: 0

Sets the thresholds for the PositionReachedCallback 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 values (max is ignored)
'>' Callback is triggered when the position is greater than the min values (max is ignored)

The following constants are available for this function:

For option:

  • BrickletJoystick`THRESHOLDUOPTIONUOFF = ToCharacterCode["x"][[0]]
  • BrickletJoystick`THRESHOLDUOPTIONUOUTSIDE = ToCharacterCode["o"][[0]]
  • BrickletJoystick`THRESHOLDUOPTIONUINSIDE = ToCharacterCode["i"][[0]]
  • BrickletJoystick`THRESHOLDUOPTIONUSMALLER = ToCharacterCode["<"][[0]]
  • BrickletJoystick`THRESHOLDUOPTIONUGREATER = ToCharacterCode[">"][[0]]
BrickletJoystick@GetPositionCallbackThreshold[out option, out minX, out maxX, out minY, out maxY] → Null
Output Parameters:
  • option – Type: Integer, Range: See constants, Default: ToCharacterCode["x"][[0]]
  • minX – Type: Integer, Range: [-215 to 215 - 1], Default: 0
  • maxX – Type: Integer, Range: [-215 to 215 - 1], Default: 0
  • minY – Type: Integer, Range: [-215 to 215 - 1], Default: 0
  • maxY – Type: Integer, Range: [-215 to 215 - 1], Default: 0

Returns the threshold as set by SetPositionCallbackThreshold[].

The following constants are available for this function:

For option:

  • BrickletJoystick`THRESHOLDUOPTIONUOFF = ToCharacterCode["x"][[0]]
  • BrickletJoystick`THRESHOLDUOPTIONUOUTSIDE = ToCharacterCode["o"][[0]]
  • BrickletJoystick`THRESHOLDUOPTIONUINSIDE = ToCharacterCode["i"][[0]]
  • BrickletJoystick`THRESHOLDUOPTIONUSMALLER = ToCharacterCode["<"][[0]]
  • BrickletJoystick`THRESHOLDUOPTIONUGREATER = ToCharacterCode[">"][[0]]
BrickletJoystick@SetAnalogValueCallbackThreshold[option, minX, maxX, minY, maxY] → Null
Parameters:
  • option – Type: Integer, Range: See constants, Default: ToCharacterCode["x"][[0]]
  • minX – Type: Integer, Range: [0 to 216 - 1], Default: 0
  • maxX – Type: Integer, Range: [0 to 216 - 1], Default: 0
  • minY – Type: Integer, Range: [0 to 216 - 1], Default: 0
  • maxY – Type: Integer, Range: [0 to 216 - 1], Default: 0

Sets the thresholds for the AnalogValueReachedCallback callback.

The following options are possible:

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

The following constants are available for this function:

For option:

  • BrickletJoystick`THRESHOLDUOPTIONUOFF = ToCharacterCode["x"][[0]]
  • BrickletJoystick`THRESHOLDUOPTIONUOUTSIDE = ToCharacterCode["o"][[0]]
  • BrickletJoystick`THRESHOLDUOPTIONUINSIDE = ToCharacterCode["i"][[0]]
  • BrickletJoystick`THRESHOLDUOPTIONUSMALLER = ToCharacterCode["<"][[0]]
  • BrickletJoystick`THRESHOLDUOPTIONUGREATER = ToCharacterCode[">"][[0]]
BrickletJoystick@GetAnalogValueCallbackThreshold[out option, out minX, out maxX, out minY, out maxY] → Null
Output Parameters:
  • option – Type: Integer, Range: See constants, Default: ToCharacterCode["x"][[0]]
  • minX – Type: Integer, Range: [0 to 216 - 1], Default: 0
  • maxX – Type: Integer, Range: [0 to 216 - 1], Default: 0
  • minY – Type: Integer, Range: [0 to 216 - 1], Default: 0
  • maxY – Type: Integer, Range: [0 to 216 - 1], Default: 0

Returns the threshold as set by SetAnalogValueCallbackThreshold[].

The following constants are available for this function:

For option:

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

Sets the period with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

BrickletJoystick@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[joystick@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 BrickletJoystick@PositionCallback[sender, x, y]
Callback Parameters:
  • sender – Type: NETObject[BrickletJoystick]
  • x – Type: Integer, Range: [-100 to 100]
  • y – Type: Integer, Range: [-100 to 100]

This callback is triggered periodically with the period that is set by SetPositionCallbackPeriod[]. The parameter is the position of the joystick.

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

event BrickletJoystick@AnalogValueCallback[sender, x, y]
Callback Parameters:
  • sender – Type: NETObject[BrickletJoystick]
  • x – Type: Integer, Range: [0 to 4095]
  • y – Type: Integer, Range: [0 to 4095]

This callback is triggered periodically with the period that is set by SetAnalogValueCallbackPeriod[]. The parameters are the analog values of the joystick.

The AnalogValueCallback callback is only triggered if the values have changed since the last triggering.

event BrickletJoystick@PositionReachedCallback[sender, x, y]
Callback Parameters:
  • sender – Type: NETObject[BrickletJoystick]
  • x – Type: Integer, Range: [-100 to 100]
  • y – Type: Integer, Range: [-100 to 100]

This callback is triggered when the threshold as set by SetPositionCallbackThreshold[] is reached. The parameters are the position of the joystick.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by SetDebouncePeriod[].

event BrickletJoystick@AnalogValueReachedCallback[sender, x, y]
Callback Parameters:
  • sender – Type: NETObject[BrickletJoystick]
  • x – Type: Integer, Range: [0 to 4095]
  • y – Type: Integer, Range: [0 to 4095]

This callback is triggered when the threshold as set by SetAnalogValueCallbackThreshold[] is reached. The parameters are the analog values of the joystick.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by SetDebouncePeriod[].

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

This callback is triggered when the button is pressed.

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

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.

BrickletJoystick@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.

BrickletJoystick@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 send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • BrickletJoystick`FUNCTIONUCALIBRATE = 4
  • BrickletJoystick`FUNCTIONUSETUPOSITIONUCALLBACKUPERIOD = 5
  • BrickletJoystick`FUNCTIONUSETUANALOGUVALUEUCALLBACKUPERIOD = 7
  • BrickletJoystick`FUNCTIONUSETUPOSITIONUCALLBACKUTHRESHOLD = 9
  • BrickletJoystick`FUNCTIONUSETUANALOGUVALUEUCALLBACKUTHRESHOLD = 11
  • BrickletJoystick`FUNCTIONUSETUDEBOUNCEUPERIOD = 13
BrickletJoystick@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 send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • BrickletJoystick`FUNCTIONUCALIBRATE = 4
  • BrickletJoystick`FUNCTIONUSETUPOSITIONUCALLBACKUPERIOD = 5
  • BrickletJoystick`FUNCTIONUSETUANALOGUVALUEUCALLBACKUPERIOD = 7
  • BrickletJoystick`FUNCTIONUSETUPOSITIONUCALLBACKUTHRESHOLD = 9
  • BrickletJoystick`FUNCTIONUSETUANALOGUVALUEUCALLBACKUTHRESHOLD = 11
  • BrickletJoystick`FUNCTIONUSETUDEBOUNCEUPERIOD = 13
BrickletJoystick@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

BrickletJoystick`DEVICEUIDENTIFIER

This constant is used to identify a Joystick 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.

BrickletJoystick`DEVICEDISPLAYNAME

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