Python - Humidity Bricklet

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

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_humidity import BrickletHumidity

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

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

    # Get current humidity
    humidity = h.get_humidity()
    print("Humidity: " + str(humidity/10.0) + " %RH")

    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 Humidity Bricklet

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_humidity import BrickletHumidity

# Callback function for humidity callback
def cb_humidity(humidity):
    print("Humidity: " + str(humidity/10.0) + " %RH")

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

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

    # Register humidity callback to function cb_humidity
    h.register_callback(h.CALLBACK_HUMIDITY, cb_humidity)

    # Set period for humidity callback to 1s (1000ms)
    # Note: The humidity callback is only called every second
    #       if the humidity has changed since the last call!
    h.set_humidity_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 Humidity Bricklet

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_humidity import BrickletHumidity

# Callback function for humidity reached callback
def cb_humidity_reached(humidity):
    print("Humidity: " + str(humidity/10.0) + " %RH")
    print("Recommended humidity for human comfort is 30 to 60 %RH.")

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    h = BrickletHumidity(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)
    h.set_debounce_period(10000)

    # Register humidity reached callback to function cb_humidity_reached
    h.register_callback(h.CALLBACK_HUMIDITY_REACHED, cb_humidity_reached)

    # Configure threshold for humidity "outside of 30 to 60 %RH"
    h.set_humidity_callback_threshold("o", 30*10, 60*10)

    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.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 methods listed below are thread-safe.

Basic Functions

BrickletHumidity(uid, ipcon)
Parameters:
  • uid – Type: str
  • ipcon – Type: IPConnection
Returns:
  • humidity – Type: BrickletHumidity

Creates an object with the unique device ID uid:

humidity = BrickletHumidity("YOUR_DEVICE_UID", ipcon)

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

BrickletHumidity.get_humidity()
Returns:
  • humidity – Type: int, Range: [0 to 216 - 1]

Returns the humidity of the sensor. The value has a range of 0 to 1000 and is given in %RH/10 (Relative Humidity), i.e. a value of 421 means that a humidity of 42.1 %RH is measured.

If you want to get the humidity periodically, it is recommended to use the CALLBACK_HUMIDITY callback and set the period with set_humidity_callback_period().

Advanced Functions

BrickletHumidity.get_analog_value()
Returns:
  • value – Type: int, Range: [0 to 216 - 1]

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_humidity() is averaged over several samples to yield less noise, while get_analog_value() gives back raw unfiltered analog values. The returned humidity value is calibrated for room temperatures, if you use the sensor in extreme cold or extreme warm environments, you might want to calculate the humidity from the analog value yourself. See the HIH 5030 datasheet.

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

BrickletHumidity.get_api_version()
Returns:
  • api_version – Type: [int, ...], Length: 3, Range: [0 to 255]

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.

BrickletHumidity.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:

  • BrickletHumidity.FUNCTION_SET_HUMIDITY_CALLBACK_PERIOD = 3
  • BrickletHumidity.FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • BrickletHumidity.FUNCTION_SET_HUMIDITY_CALLBACK_THRESHOLD = 7
  • BrickletHumidity.FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • BrickletHumidity.FUNCTION_SET_DEBOUNCE_PERIOD = 11
BrickletHumidity.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:

  • BrickletHumidity.FUNCTION_SET_HUMIDITY_CALLBACK_PERIOD = 3
  • BrickletHumidity.FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • BrickletHumidity.FUNCTION_SET_HUMIDITY_CALLBACK_THRESHOLD = 7
  • BrickletHumidity.FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • BrickletHumidity.FUNCTION_SET_DEBOUNCE_PERIOD = 11
BrickletHumidity.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.

BrickletHumidity.get_identity()
Return Object:
  • uid – Type: str, Length: up to 8
  • connected_uid – Type: str, Length: up to 8
  • position – Type: chr
  • hardware_version – Type: [int, ...], Length: 3, Range: [0 to 255]
  • firmware_version – Type: [int, ...], Length: 3, 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' or 'd'.

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

Callback Configuration Functions

BrickletHumidity.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.

BrickletHumidity.set_humidity_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_HUMIDITY callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_HUMIDITY callback is only triggered if the humidity has changed since the last triggering.

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

Returns the period as set by set_humidity_callback_period().

BrickletHumidity.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 value has changed since the last triggering.

BrickletHumidity.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().

BrickletHumidity.set_humidity_callback_threshold(option, min, max)
Parameters:
  • option – Type: chr, Range: See constants, Default: "x"
  • min – Type: int, Range: [0 to 216 - 1]
  • max – Type: int, Range: [0 to 216 - 1]
Returns:
  • None

Sets the thresholds for the CALLBACK_HUMIDITY_REACHED callback.

The following options are possible:

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

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

The following constants are available for this function:

For option:

  • BrickletHumidity.THRESHOLD_OPTION_OFF = "x"
  • BrickletHumidity.THRESHOLD_OPTION_OUTSIDE = "o"
  • BrickletHumidity.THRESHOLD_OPTION_INSIDE = "i"
  • BrickletHumidity.THRESHOLD_OPTION_SMALLER = "<"
  • BrickletHumidity.THRESHOLD_OPTION_GREATER = ">"
BrickletHumidity.get_humidity_callback_threshold()
Return Object:
  • option – Type: chr, Range: See constants, Default: "x"
  • min – Type: int, Range: [0 to 216 - 1]
  • max – Type: int, Range: [0 to 216 - 1]

Returns the threshold as set by set_humidity_callback_threshold().

The following constants are available for this function:

For option:

  • BrickletHumidity.THRESHOLD_OPTION_OFF = "x"
  • BrickletHumidity.THRESHOLD_OPTION_OUTSIDE = "o"
  • BrickletHumidity.THRESHOLD_OPTION_INSIDE = "i"
  • BrickletHumidity.THRESHOLD_OPTION_SMALLER = "<"
  • BrickletHumidity.THRESHOLD_OPTION_GREATER = ">"
BrickletHumidity.set_analog_value_callback_threshold(option, min, max)
Parameters:
  • option – Type: chr, Range: See constants, Default: "x"
  • min – Type: int, Range: [0 to 216 - 1]
  • max – Type: int, Range: [0 to 216 - 1]
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 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:

For option:

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

Returns the threshold as set by set_analog_value_callback_threshold().

The following constants are available for this function:

For option:

  • BrickletHumidity.THRESHOLD_OPTION_OFF = "x"
  • BrickletHumidity.THRESHOLD_OPTION_OUTSIDE = "o"
  • BrickletHumidity.THRESHOLD_OPTION_INSIDE = "i"
  • BrickletHumidity.THRESHOLD_OPTION_SMALLER = "<"
  • BrickletHumidity.THRESHOLD_OPTION_GREATER = ">"
BrickletHumidity.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.

BrickletHumidity.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)

humidity.register_callback(BrickletHumidity.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.

BrickletHumidity.CALLBACK_HUMIDITY
Callback Parameters:
  • humidity – Type: int, Range: [0 to 216 - 1]

This callback is triggered periodically with the period that is set by set_humidity_callback_period(). The parameter is the humidity of the sensor.

The CALLBACK_HUMIDITY callback is only triggered if the humidity has changed since the last triggering.

BrickletHumidity.CALLBACK_ANALOG_VALUE
Callback Parameters:
  • value – Type: int, Range: [0 to 216 - 1]

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 sensor.

The CALLBACK_ANALOG_VALUE callback is only triggered if the humidity has changed since the last triggering.

BrickletHumidity.CALLBACK_HUMIDITY_REACHED
Callback Parameters:
  • humidity – Type: int, Range: [0 to 216 - 1]

This callback is triggered when the threshold as set by set_humidity_callback_threshold() is reached. The parameter is the humidity of the sensor.

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

BrickletHumidity.CALLBACK_ANALOG_VALUE_REACHED
Callback Parameters:
  • value – Type: int, Range: [0 to 216 - 1]

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 sensor.

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

Constants

BrickletHumidity.DEVICE_IDENTIFIER

This constant is used to identify a Humidity 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.

BrickletHumidity.DEVICE_DISPLAY_NAME

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