This is the description of the Python API bindings for the Ambient Light Bricklet. General information and technical specifications for the Ambient Light Bricklet are summarized in its hardware description.
An installation guide for the Python 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 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change to your UID
from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_ambient_light import AmbientLight
if __name__ == "__main__":
ipcon = IPConnection() # Create IP connection
al = AmbientLight(UID, ipcon) # Create device object
ipcon.connect(HOST, PORT) # Connect to brickd
# Don't use device before ipcon is connected
# Get current illuminance (unit is Lux/10)
illuminance = al.get_illuminance()/10.0
print('Illuminance: ' + str(illuminance) + ' Lux')
raw_input('Press key to exit\n') # Use input() in Python 3
ipcon.disconnect()
|
Download (example_callback.py)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change to your UID
from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_ambient_light import AmbientLight
# Callback function for illuminance callback (parameter has unit Lux/10)
def cb_illuminance(illuminance):
print('Illuminance: ' + str(illuminance/10.0) + ' Lux')
if __name__ == "__main__":
ipcon = IPConnection() # Create IP connection
al = AmbientLight(UID, ipcon) # Create device object
ipcon.connect(HOST, PORT) # Connect to brickd
# Don't use device before ipcon is connected
# 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)
# Register illuminance callback to function cb_illuminance
al.register_callback(al.CALLBACK_ILLUMINANCE, cb_illuminance)
raw_input('Press key to exit\n') # Use input() in Python 3
ipcon.disconnect()
|
Download (example_threshold.py)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change to your UID
from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_ambient_light import AmbientLight
# Callback for illuminance greater than 200 Lux
def cb_reached(illuminance):
print('We have ' + str(illuminance/10.0) + ' Lux.')
print('Too bright, close the curtains!')
if __name__ == "__main__":
ipcon = IPConnection() # Create IP connection
al = AmbientLight(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 threshold reached callback to function cb_reached
al.register_callback(al.CALLBACK_ILLUMINANCE_REACHED, cb_reached)
# Configure threshold for "greater than 200 Lux" (unit is Lux/10)
al.set_illuminance_callback_threshold('>', 200*10, 0)
raw_input('Press key to exit\n') # Use input() in Python 3
ipcon.disconnect()
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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:
All methods listed below are thread-safe.
Parameters: |
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Creates an object with the unique device ID uid:
ambient_light = AmbientLight("YOUR_DEVICE_UID", ipcon)
This object can then be used after the IP Connection is connected (see examples above).
Return type: | int |
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Returns the illuminance of the ambient light sensor. The value has a range of 0 to 9000 and is given in Lux/10, i.e. a value of 4500 means that an illuminance of 450 Lux is measured.
If you want to get the illuminance periodically, it is recommended to use the callback CALLBACK_ILLUMINANCE and set the period with set_illuminance_callback_period().
Return type: | int |
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Returns the value as read by a 12-bit analog-to-digital converter. The value is between 0 and 4095.
Note
The value returned by get_illuminance() is 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.
Also, the analog-to-digital converter covers three different ranges that are set dynamically depending on the light intensity. It is impossible to distinguish between these ranges with the analog value.
If you want the analog value periodically, it is recommended to use the callback CALLBACK_ANALOG_VALUE and set the period with set_analog_value_callback_period().
Return type: | [int, int, int] |
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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.
Parameters: | function_id -- int |
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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.
Parameters: |
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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 and callbacks it is always disabled.
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:
Parameters: | response_expected -- bool |
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Return type: | None |
Changes the response expected flag for all setter and callback configuration functions of this device at once.
Return type: | (str, str, chr, [int, int, int], [int, int, int], int) |
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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. 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.
Parameters: |
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Return type: | None |
Registers a callback with ID id to the function callback. The available IDs with corresponding function signatures are listed below.
Parameters: | period -- int |
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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.
CALLBACK_ILLUMINANCE is only triggered if the illuminance has changed since the last triggering.
The default value is 0.
Return type: | int |
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Returns the period as set by set_illuminance_callback_period().
Parameters: | period -- int |
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Return type: | None |
Sets the period in ms with which the CALLBACK_ANALOG_VALUE callback is triggered periodically. A value of 0 turns the callback off.
CALLBACK_ANALOG_VALUE is only triggered if the analog value has changed since the last triggering.
The default value is 0.
Return type: | int |
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Returns the period as set by set_analog_value_callback_period().
Parameters: |
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Return type: | None |
Sets the thresholds for the CALLBACK_ILLUMINANCE_REACHED callback.
The following options are possible:
Option | Description |
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'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:
Return type: | (chr, int, int) |
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Returns the threshold as set by set_illuminance_callback_threshold().
The following constants are available for this function:
The returned namedtuple has the variables option, min and max.
Parameters: |
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Return type: | None |
Sets the thresholds for the CALLBACK_ANALOG_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 analog value is outside the min and max values |
'i' | Callback is triggered when the analog value is inside the min and max values |
'<' | Callback is triggered when the analog value is smaller than the min value (max is ignored) |
'>' | Callback is triggered when the analog value is greater than the min value (max is ignored) |
The default value is ('x', 0, 0).
The following constants are available for this function:
Return type: | (chr, int, int) |
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Returns the threshold as set by set_analog_value_callback_threshold().
The following constants are available for this function:
The returned namedtuple has the variables option, min and max.
Parameters: | debounce -- int |
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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.
Return type: | int |
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Returns the debounce period as set by set_debounce_period().
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.register_callback(AmbientLight.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.
Parameters: | illuminance -- int |
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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.
CALLBACK_ILLUMINANCE is only triggered if the illuminance has changed since the last triggering.
Parameters: | value -- int |
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This callback is triggered periodically with the period that is set by set_analog_value_callback_period(). The parameter is the analog value of the ambient light sensor.
CALLBACK_ANALOG_VALUE is only triggered if the analog value has changed since the last triggering.
Parameters: | illuminance -- int |
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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().
Parameters: | value -- int |
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This callback is triggered when the threshold as set by set_analog_value_callback_threshold() is reached. The parameter is the analog value 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().
This constant is used to identify a Ambient Light Bricklet.
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.