Python - Ambient Light Bricklet 2.0

This is the description of the Python API bindings for the Ambient Light Bricklet 2.0. General information and technical specifications for the Ambient Light Bricklet 2.0 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 Ambient Light Bricklet 2.0

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_ambient_light_v2 import BrickletAmbientLightV2

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    al = BrickletAmbientLightV2(UID, ipcon) # Create device object

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

    # Get current illuminance
    illuminance = al.get_illuminance()
    print("Illuminance: " + str(illuminance/100.0) + " lx")

    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 Ambient Light Bricklet 2.0

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_ambient_light_v2 import BrickletAmbientLightV2

# Callback function for illuminance callback
def cb_illuminance(illuminance):
    print("Illuminance: " + str(illuminance/100.0) + " lx")

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    al = BrickletAmbientLightV2(UID, ipcon) # Create device object

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

    # Register illuminance callback to function cb_illuminance
    al.register_callback(al.CALLBACK_ILLUMINANCE, cb_illuminance)

    # Set period for illuminance callback to 1s (1000ms)
    # Note: The illuminance callback is only called every second
    #       if the illuminance has changed since the last call!
    al.set_illuminance_callback_period(1000)

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

Threshold

Download (example_threshold.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 Ambient Light Bricklet 2.0

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_ambient_light_v2 import BrickletAmbientLightV2

# Callback function for illuminance reached callback
def cb_illuminance_reached(illuminance):
    print("Illuminance: " + str(illuminance/100.0) + " lx")
    print("Too bright, close the curtains!")

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    al = BrickletAmbientLightV2(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 10 seconds (10000ms)
    al.set_debounce_period(10000)

    # Register illuminance reached callback to function cb_illuminance_reached
    al.register_callback(al.CALLBACK_ILLUMINANCE_REACHED, cb_illuminance_reached)

    # Configure threshold for illuminance "greater than 500 lx"
    al.set_illuminance_callback_threshold(">", 500*100, 0)

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

API

Generally, every method 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.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

All methods listed below are thread-safe.

Basic Functions

BrickletAmbientLightV2(uid, ipcon)
Parameters:
  • uid -- string
  • ipcon -- IPConnection

Creates an object with the unique device ID uid:

ambient_light_v2 = BrickletAmbientLightV2("YOUR_DEVICE_UID", ipcon)

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

BrickletAmbientLightV2.get_illuminance()
Return type:int

Returns the illuminance of the ambient light sensor. The measurement range goes up to about 100000lux, but above 64000lux the precision starts to drop. The illuminance is given in lux/100, i.e. a value of 450000 means that an illuminance of 4500lux is measured.

Changed in version 2.0.2 (Plugin): An illuminance of 0lux indicates that the sensor is saturated and the configuration should be modified, see set_configuration().

If you want to get the illuminance periodically, it is recommended to use the CALLBACK_ILLUMINANCE callback and set the period with set_illuminance_callback_period().

Advanced Functions

BrickletAmbientLightV2.set_configuration(illuminance_range, integration_time)
Parameters:
  • illuminance_range -- int
  • integration_time -- int
Return type:

None

Sets the configuration. It is possible to configure an illuminance range between 0-600lux and 0-64000lux and an integration time between 50ms and 400ms.

New in version 2.0.2 (Plugin): The unlimited illuminance range allows to measure up to about 100000lux, but above 64000lux the precision starts to drop.

A smaller illuminance range increases the resolution of the data. A longer integration time will result in less noise on the data.

Changed in version 2.0.2 (Plugin): If the actual measure illuminance is out-of-range then the current illuminance range maximum +0.01lux is reported by get_illuminance() and the CALLBACK_ILLUMINANCE callback. For example, 800001 for the 0-8000lux range.

Changed in version 2.0.2 (Plugin): With a long integration time the sensor might be saturated before the measured value reaches the maximum of the selected illuminance range. In this case 0lux is reported by get_illuminance() and the CALLBACK_ILLUMINANCE callback.

If the measurement is out-of-range or the sensor is saturated then you should configure the next higher illuminance range. If the highest range is already in use, then start to reduce the integration time.

The default values are 0-8000lux illuminance range and 200ms integration time.

The following constants are available for this function:

  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_UNLIMITED = 6
  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_64000LUX = 0
  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_32000LUX = 1
  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_16000LUX = 2
  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_8000LUX = 3
  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_1300LUX = 4
  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_600LUX = 5
  • BrickletAmbientLightV2.INTEGRATION_TIME_50MS = 0
  • BrickletAmbientLightV2.INTEGRATION_TIME_100MS = 1
  • BrickletAmbientLightV2.INTEGRATION_TIME_150MS = 2
  • BrickletAmbientLightV2.INTEGRATION_TIME_200MS = 3
  • BrickletAmbientLightV2.INTEGRATION_TIME_250MS = 4
  • BrickletAmbientLightV2.INTEGRATION_TIME_300MS = 5
  • BrickletAmbientLightV2.INTEGRATION_TIME_350MS = 6
  • BrickletAmbientLightV2.INTEGRATION_TIME_400MS = 7
BrickletAmbientLightV2.get_configuration()
Return type:(int, int)

Returns the configuration as set by set_configuration().

The following constants are available for this function:

  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_UNLIMITED = 6
  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_64000LUX = 0
  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_32000LUX = 1
  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_16000LUX = 2
  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_8000LUX = 3
  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_1300LUX = 4
  • BrickletAmbientLightV2.ILLUMINANCE_RANGE_600LUX = 5
  • BrickletAmbientLightV2.INTEGRATION_TIME_50MS = 0
  • BrickletAmbientLightV2.INTEGRATION_TIME_100MS = 1
  • BrickletAmbientLightV2.INTEGRATION_TIME_150MS = 2
  • BrickletAmbientLightV2.INTEGRATION_TIME_200MS = 3
  • BrickletAmbientLightV2.INTEGRATION_TIME_250MS = 4
  • BrickletAmbientLightV2.INTEGRATION_TIME_300MS = 5
  • BrickletAmbientLightV2.INTEGRATION_TIME_350MS = 6
  • BrickletAmbientLightV2.INTEGRATION_TIME_400MS = 7

The returned namedtuple has the variables illuminance_range and integration_time.

BrickletAmbientLightV2.get_api_version()
Return type:[int, int, int]

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.

BrickletAmbientLightV2.get_response_expected(function_id)
Parameters:function_id -- int
Return 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.

See set_response_expected() for the list of function ID constants available for this function.

BrickletAmbientLightV2.set_response_expected(function_id, response_expected)
Parameters:
  • function_id -- int
  • response_expected -- bool
Return type:

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 function ID constants are available for this function:

  • BrickletAmbientLightV2.FUNCTION_SET_ILLUMINANCE_CALLBACK_PERIOD = 2
  • BrickletAmbientLightV2.FUNCTION_SET_ILLUMINANCE_CALLBACK_THRESHOLD = 4
  • BrickletAmbientLightV2.FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BrickletAmbientLightV2.FUNCTION_SET_CONFIGURATION = 8
BrickletAmbientLightV2.set_response_expected_all(response_expected)
Parameters:response_expected -- bool
Return type:None

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

BrickletAmbientLightV2.get_identity()
Return type:(str, str, chr, [int, int, int], [int, int, int], int)

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.

The returned namedtuple has the variables uid, connected_uid, position, hardware_version, firmware_version and device_identifier.

Callback Configuration Functions

BrickletAmbientLightV2.register_callback(callback_id, function)
Parameters:
  • callback_id -- int
  • function -- callable
Return type:

None

Registers the given function with the given callback_id.

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

BrickletAmbientLightV2.set_illuminance_callback_period(period)
Parameters:period -- int
Return type:None

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

The CALLBACK_ILLUMINANCE callback is only triggered if the illuminance has changed since the last triggering.

The default value is 0.

BrickletAmbientLightV2.get_illuminance_callback_period()
Return type:int

Returns the period as set by set_illuminance_callback_period().

BrickletAmbientLightV2.set_illuminance_callback_threshold(option, min, max)
Parameters:
  • option -- chr
  • min -- int
  • max -- int
Return type:

None

Sets the thresholds for the CALLBACK_ILLUMINANCE_REACHED callback.

The following options are possible:

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

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

The following constants are available for this function:

  • BrickletAmbientLightV2.THRESHOLD_OPTION_OFF = 'x'
  • BrickletAmbientLightV2.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletAmbientLightV2.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletAmbientLightV2.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletAmbientLightV2.THRESHOLD_OPTION_GREATER = '>'
BrickletAmbientLightV2.get_illuminance_callback_threshold()
Return type:(chr, int, int)

Returns the threshold as set by set_illuminance_callback_threshold().

The following constants are available for this function:

  • BrickletAmbientLightV2.THRESHOLD_OPTION_OFF = 'x'
  • BrickletAmbientLightV2.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletAmbientLightV2.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletAmbientLightV2.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletAmbientLightV2.THRESHOLD_OPTION_GREATER = '>'

The returned namedtuple has the variables option, min and max.

BrickletAmbientLightV2.set_debounce_period(debounce)
Parameters:debounce -- int
Return type:None

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

BrickletAmbientLightV2.get_debounce_period()
Return type:int

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)

ambient_light_v2.register_callback(BrickletAmbientLightV2.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.

BrickletAmbientLightV2.CALLBACK_ILLUMINANCE
Parameters:illuminance -- int

This callback is triggered periodically with the period that is set by set_illuminance_callback_period(). The parameter is the illuminance of the ambient light sensor.

The CALLBACK_ILLUMINANCE callback is only triggered if the illuminance has changed since the last triggering.

BrickletAmbientLightV2.CALLBACK_ILLUMINANCE_REACHED
Parameters:illuminance -- int

This callback is triggered when the threshold as set by set_illuminance_callback_threshold() is reached. The parameter is the illuminance of the ambient light sensor.

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

Constants

BrickletAmbientLightV2.DEVICE_IDENTIFIER

This constant is used to identify a Ambient Light Bricklet 2.0.

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

BrickletAmbientLightV2.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Ambient Light Bricklet 2.0.