This is the description of the Shell 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 Shell API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
1 2 3 4 5 6 7 8 | #!/bin/sh
# connects to localhost:4223 by default, use --host and --port to change it
# change to your UID
uid=XYZ
# get current count without reset
tinkerforge call rotary-encoder-bricklet $uid get-count false
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Download (example-callback.sh)
1 2 3 4 5 6 7 8 9 10 11 12 13 | #!/bin/sh
# connects to localhost:4223 by default, use --host and --port to change it
# change to your UID
uid=XYZ
# set period for count callback to 0.05s (50ms)
# note: the count callback is only called every second if the
# count has changed since the last call!
tinkerforge call rotary-encoder-bricklet $uid set-count-callback-period 50
# handle incoming count callbacks
tinkerforge dispatch rotary-encoder-bricklet $uid count
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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 Rotary Encoder Bricklet. It can take several options:
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The dispatch command is used to dispatch a callback of the Rotary Encoder 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 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.
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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 count callback is triggered periodically. A value of 0 turns the callback off.
count is only triggered if the count has changed since the last triggering.
The default value is 0.
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Returns the period as set by set-count-callback-period.
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Output: | no output |
Sets the thresholds for the count-reached callback.
The following options are possible:
Option | Description |
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'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 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-count-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 thresholds
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 rotary-encoder-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-count-callback-period. The parameter is the count of the encoder.
count is only triggered if the count has changed since the last triggering.
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This callback is triggered when the threshold as set by set-count-callback-threshold 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 set-debounce-period.
Output: | no output |
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This callback is triggered when the button is pressed.
Output: | no output |
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This callback is triggered when the button is released.