Python - Joystick Bricklet

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

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

Examples

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

Simple

Download (example_simple.py)

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#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your Joystick Bricklet

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_joystick import BrickletJoystick

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    j = BrickletJoystick(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Get current position
    x, y = j.get_position()

    print("Position [X]: " + str(x))
    print("Position [Y]: " + str(y))

    raw_input("Press key to exit\n") # Use input() in Python 3
    ipcon.disconnect()

Callback

Download (example_callback.py)

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#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your Joystick Bricklet

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_joystick import BrickletJoystick

# Callback function for pressed callback
def cb_pressed():
    print("Pressed")

# Callback function for released callback
def cb_released():
    print("Released")

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    j = BrickletJoystick(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Register pressed callback to function cb_pressed
    j.register_callback(j.CALLBACK_PRESSED, cb_pressed)

    # Register released callback to function cb_released
    j.register_callback(j.CALLBACK_RELEASED, cb_released)

    raw_input("Press key to exit\n") # Use input() in Python 3
    ipcon.disconnect()

Find Borders

Download (example_find_borders.py)

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#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your Joystick Bricklet

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_joystick import BrickletJoystick

# Callback function for position reached callback
def cb_position_reached(x, y):
    if y == 100:
        print('Top')
    elif y == -100:
        print('Bottom')

    if x == 100:
        print('Right')
    elif x == -100:
        print('Left')

    print("")

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    j = BrickletJoystick(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Get threshold callbacks with a debounce time of 0.2 seconds (200ms)
    j.set_debounce_period(200)

    # Register position reached callback to function cb_position_reached
    j.register_callback(j.CALLBACK_POSITION_REACHED, cb_position_reached)

    # Configure threshold for position "outside of -99, -99 to 99, 99"
    j.set_position_callback_threshold("o", -99, 99, -99, 99)

    raw_input("Press key to exit\n") # Use input() in Python 3
    ipcon.disconnect()

API

Generally, every function of the Python bindings can throw an tinkerforge.ip_connection.Error exception that has a value and a description property. value can have different values:

  • Error.TIMEOUT = -1
  • Error.NOT_ADDED = -6 (unused since Python bindings version 2.0.0)
  • Error.ALREADY_CONNECTED = -7
  • Error.NOT_CONNECTED = -8
  • Error.INVALID_PARAMETER = -9
  • Error.NOT_SUPPORTED = -10
  • Error.UNKNOWN_ERROR_CODE = -11
  • Error.STREAM_OUT_OF_SYNC = -12
  • Error.INVALID_UID = -13
  • Error.NON_ASCII_CHAR_IN_SECRET = -14

All functions listed below are thread-safe.

Basic Functions

BrickletJoystick(uid, ipcon)
Parameters:
  • uid – Type: str
  • ipcon – Type: IPConnection
Returns:
  • joystick – Type: BrickletJoystick

Creates an object with the unique device ID uid:

joystick = BrickletJoystick("YOUR_DEVICE_UID", ipcon)

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

BrickletJoystick.get_position()
Return Object:
  • x – Type: int, Range: [-100 to 100]
  • y – Type: int, Range: [-100 to 100]

Returns the position of the joystick. The middle position of the joystick is x=0, y=0. The returned values are averaged and calibrated (see calibrate()).

If you want to get the position periodically, it is recommended to use the CALLBACK_POSITION callback and set the period with set_position_callback_period().

BrickletJoystick.is_pressed()
Returns:
  • pressed – Type: bool

Returns true if the button is pressed and false otherwise.

It is recommended to use the CALLBACK_PRESSED and CALLBACK_RELEASED callbacks to handle the button.

Advanced Functions

BrickletJoystick.get_analog_value()
Return Object:
  • x – Type: int, Range: [0 to 4095]
  • y – Type: int, Range: [0 to 4095]

Returns the values as read by a 12-bit analog-to-digital converter.

Note

The values returned by get_position() are averaged over several samples to yield less noise, while get_analog_value() gives back raw unfiltered analog values. The only reason to use get_analog_value() is, if you need the full resolution of the analog-to-digital converter.

If you want the analog values periodically, it is recommended to use the CALLBACK_ANALOG_VALUE callback and set the period with set_analog_value_callback_period().

BrickletJoystick.calibrate()
Returns:
  • None

Calibrates the middle position of the joystick. If your Joystick Bricklet does not return x=0 and y=0 in the middle position, call this function while the joystick is standing still in the middle position.

The resulting calibration will be saved on the EEPROM of the Joystick Bricklet, thus you only have to calibrate it once.

BrickletJoystick.get_identity()
Return Object:
  • uid – Type: str, Length: up to 8
  • connected_uid – Type: str, Length: up to 8
  • position – Type: chr, Range: ["a" to "h", "i", "z"]
  • hardware_version – Type: [int, ...], Length: 3
    • 0: major – Type: int, Range: [0 to 255]
    • 1: minor – Type: int, Range: [0 to 255]
    • 2: revision – Type: int, Range: [0 to 255]
  • firmware_version – Type: [int, ...], Length: 3
    • 0: major – Type: int, Range: [0 to 255]
    • 1: minor – Type: int, Range: [0 to 255]
    • 2: revision – Type: int, Range: [0 to 255]
  • device_identifier – Type: int, Range: [0 to 216 - 1]

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', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as position 'z'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

BrickletJoystick.register_callback(callback_id, function)
Parameters:
  • callback_id – Type: int
  • function – Type: callable
Returns:
  • None

Registers the given function with the given callback_id.

The available callback IDs with corresponding function signatures are listed below.

BrickletJoystick.set_position_callback_period(period)
Parameters:
  • period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Returns:
  • None

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

The CALLBACK_POSITION callback is only triggered if the position has changed since the last triggering.

BrickletJoystick.get_position_callback_period()
Returns:
  • period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by set_position_callback_period().

BrickletJoystick.set_analog_value_callback_period(period)
Parameters:
  • period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Returns:
  • None

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

The CALLBACK_ANALOG_VALUE callback is only triggered if the analog values have changed since the last triggering.

BrickletJoystick.get_analog_value_callback_period()
Returns:
  • period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by set_analog_value_callback_period().

BrickletJoystick.set_position_callback_threshold(option, min_x, max_x, min_y, max_y)
Parameters:
  • option – Type: chr, Range: See constants, Default: "x"
  • min_x – Type: int, Range: [-215 to 215 - 1], Default: 0
  • max_x – Type: int, Range: [-215 to 215 - 1], Default: 0
  • min_y – Type: int, Range: [-215 to 215 - 1], Default: 0
  • max_y – Type: int, Range: [-215 to 215 - 1], Default: 0
Returns:
  • None

Sets the thresholds for the CALLBACK_POSITION_REACHED callback.

The following options are possible:

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

The following constants are available for this function:

For option:

  • BrickletJoystick.THRESHOLD_OPTION_OFF = "x"
  • BrickletJoystick.THRESHOLD_OPTION_OUTSIDE = "o"
  • BrickletJoystick.THRESHOLD_OPTION_INSIDE = "i"
  • BrickletJoystick.THRESHOLD_OPTION_SMALLER = "<"
  • BrickletJoystick.THRESHOLD_OPTION_GREATER = ">"
BrickletJoystick.get_position_callback_threshold()
Return Object:
  • option – Type: chr, Range: See constants, Default: "x"
  • min_x – Type: int, Range: [-215 to 215 - 1], Default: 0
  • max_x – Type: int, Range: [-215 to 215 - 1], Default: 0
  • min_y – Type: int, Range: [-215 to 215 - 1], Default: 0
  • max_y – Type: int, Range: [-215 to 215 - 1], Default: 0

Returns the threshold as set by set_position_callback_threshold().

The following constants are available for this function:

For option:

  • BrickletJoystick.THRESHOLD_OPTION_OFF = "x"
  • BrickletJoystick.THRESHOLD_OPTION_OUTSIDE = "o"
  • BrickletJoystick.THRESHOLD_OPTION_INSIDE = "i"
  • BrickletJoystick.THRESHOLD_OPTION_SMALLER = "<"
  • BrickletJoystick.THRESHOLD_OPTION_GREATER = ">"
BrickletJoystick.set_analog_value_callback_threshold(option, min_x, max_x, min_y, max_y)
Parameters:
  • option – Type: chr, Range: See constants, Default: "x"
  • min_x – Type: int, Range: [0 to 216 - 1], Default: 0
  • max_x – Type: int, Range: [0 to 216 - 1], Default: 0
  • min_y – Type: int, Range: [0 to 216 - 1], Default: 0
  • max_y – Type: int, Range: [0 to 216 - 1], Default: 0
Returns:
  • None

Sets the thresholds for the CALLBACK_ANALOG_VALUE_REACHED callback.

The following options are possible:

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

The following constants are available for this function:

For option:

  • BrickletJoystick.THRESHOLD_OPTION_OFF = "x"
  • BrickletJoystick.THRESHOLD_OPTION_OUTSIDE = "o"
  • BrickletJoystick.THRESHOLD_OPTION_INSIDE = "i"
  • BrickletJoystick.THRESHOLD_OPTION_SMALLER = "<"
  • BrickletJoystick.THRESHOLD_OPTION_GREATER = ">"
BrickletJoystick.get_analog_value_callback_threshold()
Return Object:
  • option – Type: chr, Range: See constants, Default: "x"
  • min_x – Type: int, Range: [0 to 216 - 1], Default: 0
  • max_x – Type: int, Range: [0 to 216 - 1], Default: 0
  • min_y – Type: int, Range: [0 to 216 - 1], Default: 0
  • max_y – Type: int, Range: [0 to 216 - 1], Default: 0

Returns the threshold as set by set_analog_value_callback_threshold().

The following constants are available for this function:

For option:

  • BrickletJoystick.THRESHOLD_OPTION_OFF = "x"
  • BrickletJoystick.THRESHOLD_OPTION_OUTSIDE = "o"
  • BrickletJoystick.THRESHOLD_OPTION_INSIDE = "i"
  • BrickletJoystick.THRESHOLD_OPTION_SMALLER = "<"
  • BrickletJoystick.THRESHOLD_OPTION_GREATER = ">"
BrickletJoystick.set_debounce_period(debounce)
Parameters:
  • debounce – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100
Returns:
  • None

Sets the period with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

BrickletJoystick.get_debounce_period()
Returns:
  • debounce – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Returns the debounce period as set by set_debounce_period().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the register_callback() function of the device object. The first parameter is the callback ID and the second parameter the callback function:

def my_callback(param):
    print(param)

joystick.register_callback(BrickletJoystick.CALLBACK_EXAMPLE, my_callback)

The available constants with inherent number and 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.

BrickletJoystick.CALLBACK_POSITION
Callback Parameters:
  • x – Type: int, Range: [-100 to 100]
  • y – Type: int, Range: [-100 to 100]

This callback is triggered periodically with the period that is set by set_position_callback_period(). The parameter is the position of the joystick.

The CALLBACK_POSITION callback is only triggered if the position has changed since the last triggering.

BrickletJoystick.CALLBACK_ANALOG_VALUE
Callback Parameters:
  • x – Type: int, Range: [0 to 4095]
  • y – Type: int, Range: [0 to 4095]

This callback is triggered periodically with the period that is set by set_analog_value_callback_period(). The parameters are the analog values of the joystick.

The CALLBACK_ANALOG_VALUE callback is only triggered if the values have changed since the last triggering.

BrickletJoystick.CALLBACK_POSITION_REACHED
Callback Parameters:
  • x – Type: int, Range: [-100 to 100]
  • y – Type: int, Range: [-100 to 100]

This callback is triggered when the threshold as set by set_position_callback_threshold() is reached. The parameters are the position of the joystick.

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

BrickletJoystick.CALLBACK_ANALOG_VALUE_REACHED
Callback Parameters:
  • x – Type: int, Range: [0 to 4095]
  • y – Type: int, Range: [0 to 4095]

This callback is triggered when the threshold as set by set_analog_value_callback_threshold() is reached. The parameters are the analog values of the joystick.

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

BrickletJoystick.CALLBACK_PRESSED
Callback Parameters:
  • no parameters

This callback is triggered when the button is pressed.

BrickletJoystick.CALLBACK_RELEASED
Callback Parameters:
  • no parameters

This callback is triggered when the button is released.

Virtual Functions

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

BrickletJoystick.get_api_version()
Return Object:
  • api_version – Type: [int, ...], Length: 3
    • 0: major – Type: int, Range: [0 to 255]
    • 1: minor – Type: int, Range: [0 to 255]
    • 2: revision – Type: int, Range: [0 to 255]

Returns the version of the API definition 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.

BrickletJoystick.get_response_expected(function_id)
Parameters:
  • function_id – Type: int, Range: See constants
Returns:
  • response_expected – Type: bool

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 set_response_expected(). 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.

The following constants are available for this function:

For function_id:

  • BrickletJoystick.FUNCTION_CALIBRATE = 4
  • BrickletJoystick.FUNCTION_SET_POSITION_CALLBACK_PERIOD = 5
  • BrickletJoystick.FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 7
  • BrickletJoystick.FUNCTION_SET_POSITION_CALLBACK_THRESHOLD = 9
  • BrickletJoystick.FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 11
  • BrickletJoystick.FUNCTION_SET_DEBOUNCE_PERIOD = 13
BrickletJoystick.set_response_expected(function_id, response_expected)
Parameters:
  • function_id – Type: int, Range: See constants
  • response_expected – Type: bool
Returns:
  • None

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 constants are available for this function:

For function_id:

  • BrickletJoystick.FUNCTION_CALIBRATE = 4
  • BrickletJoystick.FUNCTION_SET_POSITION_CALLBACK_PERIOD = 5
  • BrickletJoystick.FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 7
  • BrickletJoystick.FUNCTION_SET_POSITION_CALLBACK_THRESHOLD = 9
  • BrickletJoystick.FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 11
  • BrickletJoystick.FUNCTION_SET_DEBOUNCE_PERIOD = 13
BrickletJoystick.set_response_expected_all(response_expected)
Parameters:
  • response_expected – Type: bool
Returns:
  • None

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

Constants

BrickletJoystick.DEVICE_IDENTIFIER

This constant is used to identify a Joystick Bricklet.

The get_identity() function and the IPConnection.CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

BrickletJoystick.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Joystick Bricklet.