This is the description of the Python API bindings for the Barometer Bricklet 2.0. General information and technical specifications for the Barometer Bricklet 2.0 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 25 26 27 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your Barometer Bricklet 2.0
from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_barometer_v2 import BrickletBarometerV2
if __name__ == "__main__":
ipcon = IPConnection() # Create IP connection
b = BrickletBarometerV2(UID, ipcon) # Create device object
ipcon.connect(HOST, PORT) # Connect to brickd
# Don't use device before ipcon is connected
# Get current air pressure
air_pressure = b.get_air_pressure()
print("Air Pressure: " + str(air_pressure/1000.0) + " hPa")
# Get current altitude
altitude = b.get_altitude()
print("Altitude: " + str(altitude/1000.0) + " m")
input("Press key to exit\n") # Use raw_input() in Python 2
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 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your Barometer Bricklet 2.0
from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_barometer_v2 import BrickletBarometerV2
# Callback function for air pressure callback
def cb_air_pressure(air_pressure):
print("Air Pressure: " + str(air_pressure/1000.0) + " hPa")
if __name__ == "__main__":
ipcon = IPConnection() # Create IP connection
b = BrickletBarometerV2(UID, ipcon) # Create device object
ipcon.connect(HOST, PORT) # Connect to brickd
# Don't use device before ipcon is connected
# Register air pressure callback to function cb_air_pressure
b.register_callback(b.CALLBACK_AIR_PRESSURE, cb_air_pressure)
# Set period for air pressure callback to 1s (1000ms) without a threshold
b.set_air_pressure_callback_configuration(1000, False, "x", 0, 0)
input("Press key to exit\n") # Use raw_input() in Python 2
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 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your Barometer Bricklet 2.0
from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_barometer_v2 import BrickletBarometerV2
# Callback function for air pressure callback
def cb_air_pressure(air_pressure):
print("Air Pressure: " + str(air_pressure/1000.0) + " hPa")
print("Enjoy the potentially good weather!")
if __name__ == "__main__":
ipcon = IPConnection() # Create IP connection
b = BrickletBarometerV2(UID, ipcon) # Create device object
ipcon.connect(HOST, PORT) # Connect to brickd
# Don't use device before ipcon is connected
# Register air pressure callback to function cb_air_pressure
b.register_callback(b.CALLBACK_AIR_PRESSURE, cb_air_pressure)
# Configure threshold for air pressure "greater than 1025 hPa"
# with a debounce period of 1s (1000ms)
b.set_air_pressure_callback_configuration(1000, False, ">", 1025*1000, 0)
input("Press key to exit\n") # Use raw_input() in Python 2
ipcon.disconnect()
|
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:
All functions listed below are thread-safe.
BrickletBarometerV2
(uid, ipcon)¶Parameters: |
|
---|---|
Returns: |
|
Creates an object with the unique device ID uid
:
barometer_v2 = BrickletBarometerV2("YOUR_DEVICE_UID", ipcon)
This object can then be used after the IP Connection is connected.
BrickletBarometerV2.
get_air_pressure
()¶Returns: |
|
---|
Returns the measured air pressure.
If you want to get the value periodically, it is recommended to use the
CALLBACK_AIR_PRESSURE
callback. You can set the callback configuration
with set_air_pressure_callback_configuration()
.
BrickletBarometerV2.
get_altitude
()¶Returns: |
|
---|
Returns the relative altitude of the air pressure sensor. The value
is calculated based on the difference between the
current air pressure and the reference air pressure that can be set
with set_reference_air_pressure()
.
If you want to get the value periodically, it is recommended to use the
CALLBACK_ALTITUDE
callback. You can set the callback configuration
with set_altitude_callback_configuration()
.
BrickletBarometerV2.
get_temperature
()¶Returns: |
|
---|
Returns the temperature of the air pressure sensor.
This temperature is used internally for temperature compensation of the air pressure measurement. It is not as accurate as the temperature measured by the Temperature Bricklet 2.0 or the Temperature IR Bricklet 2.0.
If you want to get the value periodically, it is recommended to use the
CALLBACK_TEMPERATURE
callback. You can set the callback configuration
with set_temperature_callback_configuration()
.
BrickletBarometerV2.
set_moving_average_configuration
(moving_average_length_air_pressure, moving_average_length_temperature)¶Parameters: |
|
---|---|
Returns: |
|
Sets the length of a moving averaging for the air pressure and temperature measurements.
Setting the length to 1 will turn the averaging off. With less averaging, there is more noise on the data.
If you want to do long term measurements the longest moving average will give the cleanest results.
BrickletBarometerV2.
get_moving_average_configuration
()¶Return Object: |
|
---|
Returns the moving average configuration as set by
set_moving_average_configuration()
.
BrickletBarometerV2.
set_reference_air_pressure
(air_pressure)¶Parameters: |
|
---|---|
Returns: |
|
Sets the reference air pressure for the altitude calculation. Setting the reference to the current air pressure results in a calculated altitude of 0mm. Passing 0 is a shortcut for passing the current air pressure as reference.
Well known reference values are the Q codes QNH and QFE used in aviation.
BrickletBarometerV2.
get_reference_air_pressure
()¶Returns: |
|
---|
Returns the reference air pressure as set by set_reference_air_pressure()
.
BrickletBarometerV2.
set_calibration
(measured_air_pressure, actual_air_pressure)¶Parameters: |
|
---|---|
Returns: |
|
Sets the one point calibration (OPC) values for the air pressure measurement.
Before the Bricklet can be calibrated any previous calibration has to be removed
by setting measured air pressure
and actual air pressure
to 0.
Then the current air pressure has to be measured using the Bricklet
(measured air pressure
) and with an accurate reference barometer
(actual air pressure
) at the same time and passed to this function.
After proper calibration the air pressure measurement can achieve an accuracy up to 0.2 hPa.
The calibration is saved in the EEPROM of the Bricklet and only needs to be configured once.
BrickletBarometerV2.
get_calibration
()¶Return Object: |
|
---|
Returns the air pressure one point calibration values as set by
set_calibration()
.
BrickletBarometerV2.
set_sensor_configuration
(data_rate, air_pressure_low_pass_filter)¶Parameters: |
|
---|---|
Returns: |
|
Configures the data rate and air pressure low pass filter. The low pass filter cut-off frequency (if enabled) can be set to 1/9th or 1/20th of the configure data rate to decrease the noise on the air pressure data.
The low pass filter configuration only applies to the air pressure measurement. There is no low pass filter for the temperature measurement.
A higher data rate will result in a less precise temperature because of self-heating of the sensor. If the accuracy of the temperature reading is important to you, we would recommend the 1Hz data rate.
The following constants are available for this function:
For data_rate:
For air_pressure_low_pass_filter:
BrickletBarometerV2.
get_sensor_configuration
()¶Return Object: |
|
---|
Returns the sensor configuration as set by set_sensor_configuration()
.
The following constants are available for this function:
For data_rate:
For air_pressure_low_pass_filter:
BrickletBarometerV2.
get_spitfp_error_count
()¶Return Object: |
|
---|
Returns the error count for the communication between Brick and Bricklet.
The errors are divided into
The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.
BrickletBarometerV2.
set_status_led_config
(config)¶Parameters: |
|
---|---|
Returns: |
|
Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.
You can also turn the LED permanently on/off or show a heartbeat.
If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.
The following constants are available for this function:
For config:
BrickletBarometerV2.
get_status_led_config
()¶Returns: |
|
---|
Returns the configuration as set by set_status_led_config()
The following constants are available for this function:
For config:
BrickletBarometerV2.
get_chip_temperature
()¶Returns: |
|
---|
Returns the temperature as measured inside the microcontroller. The value returned is not the ambient temperature!
The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.
BrickletBarometerV2.
reset
()¶Returns: |
|
---|
Calling this function will reset the Bricklet. All configurations will be lost.
After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!
BrickletBarometerV2.
get_identity
()¶Return Object: |
|
---|
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). A Bricklet connected to an Isolator Bricklet is always at position 'z'.
The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.
BrickletBarometerV2.
register_callback
(callback_id, function)¶Parameters: |
|
---|---|
Returns: |
|
Registers the given function
with the given callback_id
.
The available callback IDs with corresponding function signatures are listed below.
BrickletBarometerV2.
set_air_pressure_callback_configuration
(period, value_has_to_change, option, min, max)¶Parameters: |
|
---|---|
Returns: |
|
The period is the period with which the CALLBACK_AIR_PRESSURE
callback is triggered
periodically. A value of 0 turns the callback off.
If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.
If it is set to false, the callback is continuously triggered with the period, independent of the value.
It is furthermore possible to constrain the callback with thresholds.
The option-parameter together with min/max sets a threshold for the CALLBACK_AIR_PRESSURE
callback.
The following options are possible:
Option | Description |
---|---|
'x' | Threshold is turned off |
'o' | Threshold is triggered when the value is outside the min and max values |
'i' | Threshold is triggered when the value is inside or equal to the min and max values |
'<' | Threshold is triggered when the value is smaller than the min value (max is ignored) |
'>' | Threshold is triggered when the value is greater than the min value (max is ignored) |
If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.
The following constants are available for this function:
For option:
BrickletBarometerV2.
get_air_pressure_callback_configuration
()¶Return Object: |
|
---|
Returns the callback configuration as set by set_air_pressure_callback_configuration()
.
The following constants are available for this function:
For option:
BrickletBarometerV2.
set_altitude_callback_configuration
(period, value_has_to_change, option, min, max)¶Parameters: |
|
---|---|
Returns: |
|
The period is the period with which the CALLBACK_ALTITUDE
callback is triggered
periodically. A value of 0 turns the callback off.
If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.
If it is set to false, the callback is continuously triggered with the period, independent of the value.
It is furthermore possible to constrain the callback with thresholds.
The option-parameter together with min/max sets a threshold for the CALLBACK_ALTITUDE
callback.
The following options are possible:
Option | Description |
---|---|
'x' | Threshold is turned off |
'o' | Threshold is triggered when the value is outside the min and max values |
'i' | Threshold is triggered when the value is inside or equal to the min and max values |
'<' | Threshold is triggered when the value is smaller than the min value (max is ignored) |
'>' | Threshold is triggered when the value is greater than the min value (max is ignored) |
If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.
The following constants are available for this function:
For option:
BrickletBarometerV2.
get_altitude_callback_configuration
()¶Return Object: |
|
---|
Returns the callback configuration as set by set_altitude_callback_configuration()
.
The following constants are available for this function:
For option:
BrickletBarometerV2.
set_temperature_callback_configuration
(period, value_has_to_change, option, min, max)¶Parameters: |
|
---|---|
Returns: |
|
The period is the period with which the CALLBACK_TEMPERATURE
callback is triggered
periodically. A value of 0 turns the callback off.
If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.
If it is set to false, the callback is continuously triggered with the period, independent of the value.
It is furthermore possible to constrain the callback with thresholds.
The option-parameter together with min/max sets a threshold for the CALLBACK_TEMPERATURE
callback.
The following options are possible:
Option | Description |
---|---|
'x' | Threshold is turned off |
'o' | Threshold is triggered when the value is outside the min and max values |
'i' | Threshold is triggered when the value is inside or equal to the min and max values |
'<' | Threshold is triggered when the value is smaller than the min value (max is ignored) |
'>' | Threshold is triggered when the value is greater than the min value (max is ignored) |
If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.
The following constants are available for this function:
For option:
BrickletBarometerV2.
get_temperature_callback_configuration
()¶Return Object: |
|
---|
Returns the callback configuration as set by set_temperature_callback_configuration()
.
The following constants are available for this function:
For option:
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)
barometer_v2.register_callback(BrickletBarometerV2.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.
BrickletBarometerV2.
CALLBACK_AIR_PRESSURE
¶Callback Parameters: |
|
---|
This callback is triggered periodically according to the configuration set by
set_air_pressure_callback_configuration()
.
The parameter is the same as get_air_pressure()
.
BrickletBarometerV2.
CALLBACK_ALTITUDE
¶Callback Parameters: |
|
---|
This callback is triggered periodically according to the configuration set by
set_altitude_callback_configuration()
.
The parameter is the same as get_altitude()
.
BrickletBarometerV2.
CALLBACK_TEMPERATURE
¶Callback Parameters: |
|
---|
This callback is triggered periodically according to the configuration set by
set_temperature_callback_configuration()
.
The parameter is the same as get_temperature()
.
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.
BrickletBarometerV2.
get_api_version
()¶Return Object: |
|
---|
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.
BrickletBarometerV2.
get_response_expected
(function_id)¶Parameters: |
|
---|---|
Returns: |
|
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 sent and errors are silently ignored, because they cannot be detected.
The following constants are available for this function:
For function_id:
BrickletBarometerV2.
set_response_expected
(function_id, response_expected)¶Parameters: |
|
---|---|
Returns: |
|
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 sent and errors are silently ignored, because they cannot be detected.
The following constants are available for this function:
For function_id:
BrickletBarometerV2.
set_response_expected_all
(response_expected)¶Parameters: |
|
---|---|
Returns: |
|
Changes the response expected flag for all setter and callback configuration functions of this device at once.
Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.
BrickletBarometerV2.
set_bootloader_mode
(mode)¶Parameters: |
|
---|---|
Returns: |
|
Sets the bootloader mode and returns the status after the requested mode change was instigated.
You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
The following constants are available for this function:
For mode:
For status:
BrickletBarometerV2.
get_bootloader_mode
()¶Returns: |
|
---|
Returns the current bootloader mode, see set_bootloader_mode()
.
The following constants are available for this function:
For mode:
BrickletBarometerV2.
set_write_firmware_pointer
(pointer)¶Parameters: |
|
---|---|
Returns: |
|
Sets the firmware pointer for write_firmware()
. The pointer has
to be increased by chunks of size 64. The data is written to flash
every 4 chunks (which equals to one page of size 256).
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
BrickletBarometerV2.
write_firmware
(data)¶Parameters: |
|
---|---|
Returns: |
|
Writes 64 Bytes of firmware at the position as written by
set_write_firmware_pointer()
before. The firmware is written
to flash every 4 chunks.
You can only write firmware in bootloader mode.
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
BrickletBarometerV2.
write_uid
(uid)¶Parameters: |
|
---|---|
Returns: |
|
Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.
We recommend that you use Brick Viewer to change the UID.
BrickletBarometerV2.
read_uid
()¶Returns: |
|
---|
Returns the current UID as an integer. Encode as Base58 to get the usual string version.
BrickletBarometerV2.
DEVICE_IDENTIFIER
¶This constant is used to identify a Barometer Bricklet 2.0.
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.
BrickletBarometerV2.
DEVICE_DISPLAY_NAME
¶This constant represents the human readable name of a Barometer Bricklet 2.0.