C# - Gas Detector Bricklet – Tinkerforge

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# C# - Gas Detector Bricklet

Note

This Bricklet is currently in the prototype stage and the software/hardware as well as the documentation is in an incomplete state.

This is the description of the C# API bindings for the Gas Detector Bricklet. General information and technical specifications for the Gas Detector Bricklet are summarized in its hardware description.

An installation guide for the C# API bindings is part of their general description.

## Examples

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

## API

Generally, every method of the C# 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 C# does not support multiple return values directly, we use the `out` keyword to return multiple values from a method.

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

All methods listed below are thread-safe.

### Basic Functions

public class `BrickletGasDetector`(String uid, IPConnection ipcon)

  Creates an object with the unique device ID `uid`:

      BrickletGasDetector gasDetector = new BrickletGasDetector("YOUR_DEVICE_UID", ipcon);

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

public int `GetValue`()

  Returns a value between 0 and 4095.

  See here for more information about the measurements.

  If you want to get the value periodically, it is recommended to use the callback `Value` and set the period with `SetValueCallbackPeriod()`.

### Advanced Functions

public void `SetMovingAverage`(byte average)

  Sets the length of a moving averaging for the measured value.

  Setting the length to 1 will turn the averaging off. With less averaging, there is more noise on the data.

  The range for the averaging is 1-100.

  The default value is 100.

public byte `GetMovingAverage`()

  Returns the length moving average as set by `SetMovingAverage()`.

public void `SetDetectorType`(byte detectorType)

  Sets the detector type.

  The following types are currently supported.

  - Type 0: MQ2 and MQ5
  - Type 1: MQ3

  The detector type is written to the EEPROM of the Bricklet, so it only has to be set once.

  You can use the Brick Viewer to set the detector type, so you likely don't need to use this function in your source code.

  The default detector type is 0.

  The following constants are available for this function:

  - BrickletGasDetector.DETECTOR_TYPE_0 = 0
  - BrickletGasDetector.DETECTOR_TYPE_1 = 1

public byte `GetDetectorType`()

  Returns the detector type as set by `SetDetectorType()`.

  The following constants are available for this function:

  - BrickletGasDetector.DETECTOR_TYPE_0 = 0
  - BrickletGasDetector.DETECTOR_TYPE_1 = 1

public void `HeaterOn`()

  Turns the internal heater on.

public void `HeaterOff`()

  Turns the internal heater off.

public bool `IsHeaterOn`()

  Returns true if the heater is on, false otherwise.

public byte[] `GetAPIVersion`()

  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.

public bool `GetResponseExpected`(byte functionId)

  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.

public void `SetResponseExpected`(byte functionId, bool responseExpected)

  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:

  - BrickletGasDetector.FUNCTION_SET_VALUE_CALLBACK_PERIOD = 2
  - BrickletGasDetector.FUNCTION_SET_VALUE_CALLBACK_THRESHOLD = 4
  - BrickletGasDetector.FUNCTION_SET_DEBOUNCE_PERIOD = 6
  - BrickletGasDetector.FUNCTION_SET_MOVING_AVERAGE = 8
  - BrickletGasDetector.FUNCTION_SET_DETECTOR_TYPE = 10
  - BrickletGasDetector.FUNCTION_HEATER_ON = 12
  - BrickletGasDetector.FUNCTION_HEATER_OFF = 13

public void `SetResponseExpectedAll`(bool responseExpected)

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

public void `GetIdentity`(out string uid, out string connectedUid, out char position, out byte[] hardwareVersion, out byte[] firmwareVersion, out int deviceIdentifier)

  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

public void `SetValueCallbackPeriod`(long period)

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

  `Value` is only triggered if the value value has changed since the last triggering.

  The default value is 0.

public long `GetValueCallbackPeriod`()

  Returns the period as set by `SetValueCallbackPeriod()`.

public void `SetValueCallbackThreshold`(char option, int min, int max)

  Sets the thresholds for the `ValueReached` callback.

  The following options are possible:

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

  The default value is ('x', 0, 0).

  The following constants are available for this function:

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

public void `GetValueCallbackThreshold`(out char option, out int min, out int max)

  Returns the threshold as set by `SetValueCallbackThreshold()`.

  The following constants are available for this function:

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

public void `SetDebouncePeriod`(long debounce)

  Sets the period in ms with which the threshold callback

  - `ValueReached`

  is triggered, if the threshold

  - `SetValueCallbackThreshold()`

  keeps being reached.

  The default value is 100.

public long `GetDebouncePeriod`()

  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 appending your callback handler to the corresponding event:

    void Callback(BrickletGasDetector sender, int value)
    {
        System.Console.WriteLine("Value: " + value);
    }

    gasDetector.ExampleCallback += Callback;

The available events 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.

public event `Value`(BrickletGasDetector sender, int value)

  This callback is triggered periodically with the period that is set by `SetValueCallbackPeriod()`. The parameter is the value value of the sensor.

  `Value` is only triggered if the value has changed since the last triggering.

public event `ValueReached`(BrickletGasDetector sender, int value)

  This callback is triggered when the threshold as set by `SetValueCallbackThreshold()` is reached. The parameter is the value of the detector.

  If the threshold keeps being reached, the callback is triggered periodically with the period as set by `SetDebouncePeriod()`.

### Constants

public int `DEVICE_IDENTIFIER`

  This constant is used to identify a Gas Detector 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.

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