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Software / API Bindings / Shell / API Reference and Examples / Bricklets / Dual Button Bricklet

Shell - Dual Button Bricklet

This is the description of the Shell API bindings for the Dual Button Bricklet. General information and technical specifications for the Dual Button Bricklet are summarized in its hardware description.

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

Examples

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

Callback

Download (example-callback.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your Dual Button Bricklet

# Handle incoming state changed callbacks
tinkerforge dispatch dual-button-bricklet $uid state-changed &

echo "Press key to exit"; read dummy

kill -- -$$ # Stop callback dispatch in background

API

Possible exit codes for all tinkerforge commands are:

  • 1: interrupted (ctrl+c)
  • 2: syntax error
  • 21: Python 2.5 or newer is required
  • 22: Python argparse module is missing
  • 23: socket error
  • 24: other exception
  • 25: invalid placeholder in format string
  • 26: authentication error
  • 201: timeout occurred
  • 209: invalid argument value
  • 210: function is not supported
  • 211: unknown error

Command Structure

The common options of the call and dispatch commands are documented here. The specific command structure is shown below.

tinkerforge call dual-button-bricklet [<option>..] <uid> <function> [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The call command is used to call a function of the Dual Button Bricklet. It can take several options:

  • --help shows help for the specific call command and exits
  • --list-functions shows a list of known functions of the Dual Button Bricklet and exits
tinkerforge dispatch dual-button-bricklet [<option>..] <uid> <callback>
Parameters:
  • <uid> -- string
  • <callback> -- string

The dispatch command is used to dispatch a callback of the Dual Button Bricklet. It can take several options:

  • --help shows help for the specific dispatch command and exits
  • --list-callbacks shows a list of known callbacks of the Dual Button Bricklet and exits
tinkerforge call dual-button-bricklet <uid> <function> [<option>..] [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The <function> to be called can take different options depending of its kind. All functions can take the following options:

  • --help shows help for the specific function and exits

Getter functions can take the following options:

  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Setter functions can take the following options:

  • --expect-response requests response and waits for it

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.

tinkerforge dispatch dual-button-bricklet <uid> <callback> [<option>..]
Parameters:
  • <uid> -- string
  • <callback> -- string

The <callback> to be dispatched can take several options:

  • --help shows help for the specific callback and exits
  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Basic Functions

tinkerforge call dual-button-bricklet <uid> set-led-state <led-l> <led-r>
Parameters:
  • <led-l> -- int (has symbols)
  • <led-r> -- int (has symbols)
Output:

no output

Sets the state of the LEDs. Possible states are:

  • 0 = AutoToggleOn: Enables auto toggle with initially enabled LED.
  • 1 = AutoToggleOff: Activates auto toggle with initially disabled LED.
  • 2 = On: Enables LED (auto toggle is disabled).
  • 3 = Off: Disables LED (auto toggle is disabled).

In auto toggle mode the LED is toggled automatically at each press of a button.

If you just want to set one of the LEDs and don't know the current state of the other LED, you can get the state with get-led-state or you can use set-selected-led-state.

The default value is (1, 1).

The following symbols are available for this function:

  • led-state-auto-toggle-on = 0, for <led-l> and <led-r>
  • led-state-auto-toggle-off = 1, for <led-l> and <led-r>
  • led-state-on = 2, for <led-l> and <led-r>
  • led-state-off = 3, for <led-l> and <led-r>
tinkerforge call dual-button-bricklet <uid> get-led-state
Output:
  • led-l -- int (has symbols)
  • led-r -- int (has symbols)

Returns the current state of the LEDs, as set by set-led-state.

The following symbols are available for this function:

  • led-state-auto-toggle-on = 0, for led-l and led-r
  • led-state-auto-toggle-off = 1, for led-l and led-r
  • led-state-on = 2, for led-l and led-r
  • led-state-off = 3, for led-l and led-r
tinkerforge call dual-button-bricklet <uid> get-button-state
Output:
  • button-l -- int (has symbols)
  • button-r -- int (has symbols)

Returns the current state for both buttons. Possible states are:

  • 0 = pressed
  • 1 = released

The following symbols are available for this function:

  • button-state-pressed = 0, for button-l and button-r
  • button-state-released = 1, for button-l and button-r

Advanced Functions

tinkerforge call dual-button-bricklet <uid> set-selected-led-state <led> <state>
Parameters:
  • <led> -- int (has symbols)
  • <state> -- int (has symbols)
Output:

no output

Sets the state of the selected LED (0 or 1).

The other LED remains untouched.

The following symbols are available for this function:

  • led-left = 0, for <led>
  • led-right = 1, for <led>
  • led-state-auto-toggle-on = 0, for <state>
  • led-state-auto-toggle-off = 1, for <state>
  • led-state-on = 2, for <state>
  • led-state-off = 3, for <state>
tinkerforge call dual-button-bricklet <uid> get-identity
Output:
  • uid -- string
  • connected-uid -- string
  • position -- char
  • hardware-version -- int,int,int
  • firmware-version -- int,int,int
  • device-identifier -- int (has symbols)

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. 

Callbacks

Callbacks can be used to receive time critical or recurring data from the device:

tinkerforge dispatch dual-button-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.

tinkerforge dispatch dual-button-bricklet <uid> state-changed
Output:
  • button-l -- int (has symbols)
  • button-r -- int (has symbols)
  • led-l -- int (has symbols)
  • led-r -- int (has symbols)

This callback is called whenever a button is pressed.

Possible states for buttons are:

  • 0 = pressed
  • 1 = released

Possible states for LEDs are:

  • 0 = AutoToggleOn: Auto toggle enabled and LED on.
  • 1 = AutoToggleOff: Auto toggle enabled and LED off.
  • 2 = On: LED on (auto toggle is disabled).
  • 3 = Off: LED off (auto toggle is disabled).

The following symbols are available for this function:

  • button-state-pressed = 0, for button-l and button-r
  • button-state-released = 1, for button-l and button-r
  • led-state-auto-toggle-on = 0, for led-l and led-r
  • led-state-auto-toggle-off = 1, for led-l and led-r
  • led-state-on = 2, for led-l and led-r
  • led-state-off = 3, for led-l and led-r