Mathematica - Hall Effect Bricklet

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

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

(*Get current edge count without reset*)
Print["Count: "<>ToString[he@GetEdgeCount[False]]]

(*Clean up*)
ipcon@Disconnect[]
ReleaseNETObject[he]
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 Hall Effect Bricklet*)

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

(*Callback function for edge count callback*)
EdgeCountCB[sender_,count_,value_]:=
 Print["Count: "<>ToString[count]]
AddEventHandler[he@EdgeCountCallback,EdgeCountCB]

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

Input["Click OK to exit"]

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

API

Generally, every method 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 method. 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

BrickletHallEffect[uid, ipcon] → hallEffect
Parameters:
  • uid -- String
  • ipcon -- NETObject[IPConnection]
Returns:
  • hallEffect -- NETObject[BrickletHallEffect]

Creates an object with the unique device ID uid:

hallEffect=NETNew["Tinkerforge.BrickletHallEffect","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.

BrickletHallEffect@GetValue[] → value
Returns:
  • value -- True/False

Returns true if a magnetic field of 35 Gauss (3.5mT) or greater is detected.

BrickletHallEffect@GetEdgeCount[resetCounter] → count
Parameters:
  • resetCounter -- True/False
Returns:
  • count -- Integer

Returns the current value of the edge counter. You can configure edge type (rising, falling, both) that is counted with SetEdgeCountConfig[].

If you set the reset counter to true, the count is set back to 0 directly after it is read.

Advanced Functions

BrickletHallEffect@SetEdgeCountConfig[edgeType, debounce] → Null
Parameters:
  • edgeType -- Integer
  • debounce -- Integer

The edge type parameter configures if rising edges, falling edges or both are counted. Possible edge types are:

  • 0 = rising (default)
  • 1 = falling
  • 2 = both

A magnetic field of 35 Gauss (3.5mT) or greater causes a falling edge and a magnetic field of 25 Gauss (2.5mT) or smaller causes a rising edge.

If a magnet comes near the Bricklet the signal goes low (falling edge), if a magnet is removed from the vicinity the signal goes high (rising edge).

The debounce time is given in ms.

Configuring an edge counter resets its value to 0.

If you don't know what any of this means, just leave it at default. The default configuration is very likely OK for you.

Default values: 0 (edge type) and 100ms (debounce time)

The following constants are available for this function:

  • BrickletHallEffect`EDGEUTYPEURISING = 0
  • BrickletHallEffect`EDGEUTYPEUFALLING = 1
  • BrickletHallEffect`EDGEUTYPEUBOTH = 2
BrickletHallEffect@GetEdgeCountConfig[out edgeType, out debounce] → Null
Parameters:
  • edgeType -- Integer
  • debounce -- Integer

Returns the edge type and debounce time as set by SetEdgeCountConfig[].

The following constants are available for this function:

  • BrickletHallEffect`EDGEUTYPEURISING = 0
  • BrickletHallEffect`EDGEUTYPEUFALLING = 1
  • BrickletHallEffect`EDGEUTYPEUBOTH = 2
BrickletHallEffect@GetAPIVersion[] → {apiVersion1, apiVersion2, apiVersion3}
Returns:
  • apiVersioni -- Integer

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.

BrickletHallEffect@GetResponseExpected[functionId] → responseExpected
Parameters:
  • functionId -- Integer
Returns:
  • responseExpected -- 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.

See SetResponseExpected[] for the list of function ID constants available for this function.

BrickletHallEffect@SetResponseExpected[functionId, responseExpected] → Null
Parameters:
  • functionId -- Integer
  • responseExpected -- 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 function ID constants are available for this function:

  • BrickletHallEffect`FUNCTIONUSETUEDGEUCOUNTUCONFIG = 3
  • BrickletHallEffect`FUNCTIONUSETUEDGEUINTERRUPT = 5
  • BrickletHallEffect`FUNCTIONUSETUEDGEUCOUNTUCALLBACKUPERIOD = 7
BrickletHallEffect@SetResponseExpectedAll[responseExpected] → Null
Parameters:
  • responseExpected -- True/False

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

BrickletHallEffect@GetIdentity[out uid, out connectedUid, out position, out {hardwareVersion1, hardwareVersion2, hardwareVersion3}, out {firmwareVersion1, firmwareVersion2, firmwareVersion3}, out deviceIdentifier] → Null
Parameters:
  • uid -- String
  • connectedUid -- String
  • position -- Integer
  • hardwareVersioni -- Integer
  • firmwareVersioni -- Integer
  • deviceIdentifier -- Integer

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.

Callback Configuration Functions

BrickletHallEffect@SetEdgeInterrupt[edges] → Null
Parameters:
  • edges -- Integer

Sets the number of edges until an interrupt is invoked.

If edges is set to n, an interrupt is invoked for every n-th detected edge.

If edges is set to 0, the interrupt is disabled.

Default value is 0.

BrickletHallEffect@GetEdgeInterrupt[] → edges
Returns:
  • edges -- Integer

Returns the edges as set by SetEdgeInterrupt[].

BrickletHallEffect@SetEdgeCountCallbackPeriod[period] → Null
Parameters:
  • period -- Integer

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

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

The default value is 0.

BrickletHallEffect@GetEdgeCountCallbackPeriod[] → period
Returns:
  • period -- Integer

Returns the period as set by SetEdgeCountCallbackPeriod[].

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[hallEffect@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 BrickletHallEffect@EdgeCountCallback[sender, count, value]
Parameters:
  • sender -- NETObject[BrickletHallEffect]
  • count -- Integer
  • value -- True/False

This callback is triggered periodically with the period that is set by SetEdgeCountCallbackPeriod[]. The parameters are the current count and the current value (see GetValue[] and GetEdgeCount[]).

The EdgeCountCallback callback is only triggered if the count or value changed since the last triggering.

Constants

BrickletHallEffect`DEVICEUIDENTIFIER

This constant is used to identify a Hall Effect Bricklet.

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

BrickletHallEffect`DEVICEDISPLAYNAME

This constant represents the human readable name of a Hall Effect Bricklet.