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 Shell 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 Shell API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
Possible exit codes for all tinkerforge commands are:
The common options of the call and dispatch commands are documented here. The specific command structure is shown below.
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The call command is used to call a function of the Gas Detector Bricklet. It can take several options:
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The dispatch command is used to dispatch a callback of the Gas Detector Bricklet. It can take several options:
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The <function> to be called can take different options depending of its kind. All functions can take the following options:
Getter functions can take the following options:
Setter functions can take the following options:
The --expect-response option for setter functions allows to detect timeouts and other error conditions calls of setters as well. The device will then send a response for this purpose. If this option is not given for a setter function then no response is send and errors are silently ignored, because they cannot be detected.
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The <callback> to be dispatched can take several options:
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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 set-value-callback-period.
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Output: | no output |
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.
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Returns the length moving average as set by set-moving-average.
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Output: | no output |
Sets the detector type.
The following types are currently supported.
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 symbols are available for this function:
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Returns the detector type as set by set-detector-type.
The following symbols are available for this function:
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Turns the internal heater on.
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Turns the internal heater off.
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Returns true if the heater is on, false otherwise.
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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.
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Output: | no output |
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.
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Returns the period as set by set-value-callback-period.
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Output: | no output |
Sets the thresholds for the value-reached callback.
The following options are possible:
Option | Description |
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'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 symbols are available for this function:
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Returns the threshold as set by set-value-callback-threshold.
The following symbols are available for this function:
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Output: | no output |
Sets the period in ms with which the threshold callback
is triggered, if the threshold
keeps being reached.
The default value is 100.
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Returns the debounce period as set by set-debounce-period.
Callbacks can be used to receive time critical or recurring data from the device:
tinkerforge dispatch gas-detector-bricklet <uid> example
The available callbacks 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.
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This callback is triggered periodically with the period that is set by set-value-callback-period. The parameter is the value value of the sensor.
value is only triggered if the value has changed since the last triggering.
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This callback is triggered when the threshold as set by set-value-callback-threshold 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 set-debounce-period.