Rust - Barometer Bricklet

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

An installation guide for the Rust API bindings is part of their general description. Additional documentation can be found on docs.rs.

Examples

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

Simple

Download (example_simple.rs)

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use std::{error::Error, io};

use tinkerforge::{barometer_bricklet::*, ip_connection::IpConnection};

const HOST: &str = "localhost";
const PORT: u16 = 4223;
const UID: &str = "XYZ"; // Change XYZ to the UID of your Barometer Bricklet.

fn main() -> Result<(), Box<dyn Error>> {
    let ipcon = IpConnection::new(); // Create IP connection.
    let b = BarometerBricklet::new(UID, &ipcon); // Create device object.

    ipcon.connect((HOST, PORT)).recv()??; // Connect to brickd.
                                          // Don't use device before ipcon is connected.

    // Get current air pressure.
    let air_pressure = b.get_air_pressure().recv()?;
    println!("Air Pressure: {} mbar", air_pressure as f32 / 1000.0);

    // Get current altitude.
    let altitude = b.get_altitude().recv()?;
    println!("Altitude: {} m", altitude as f32 / 100.0);

    println!("Press enter to exit.");
    let mut _input = String::new();
    io::stdin().read_line(&mut _input)?;
    ipcon.disconnect();
    Ok(())
}

Callback

Download (example_callback.rs)

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use std::{error::Error, io, thread};
use tinkerforge::{barometer_bricklet::*, ip_connection::IpConnection};

const HOST: &str = "localhost";
const PORT: u16 = 4223;
const UID: &str = "XYZ"; // Change XYZ to the UID of your Barometer Bricklet.

fn main() -> Result<(), Box<dyn Error>> {
    let ipcon = IpConnection::new(); // Create IP connection.
    let b = BarometerBricklet::new(UID, &ipcon); // Create device object.

    ipcon.connect((HOST, PORT)).recv()??; // Connect to brickd.
                                          // Don't use device before ipcon is connected.

    let air_pressure_receiver = b.get_air_pressure_callback_receiver();

    // Spawn thread to handle received callback messages.
    // This thread ends when the `b` object
    // is dropped, so there is no need for manual cleanup.
    thread::spawn(move || {
        for air_pressure in air_pressure_receiver {
            println!("Air Pressure: {} mbar", air_pressure as f32 / 1000.0);
        }
    });

    // Set period for air pressure receiver to 1s (1000ms).
    // Note: The air pressure callback is only called every second
    //       if the air pressure has changed since the last call!
    b.set_air_pressure_callback_period(1000);

    println!("Press enter to exit.");
    let mut _input = String::new();
    io::stdin().read_line(&mut _input)?;
    ipcon.disconnect();
    Ok(())
}

Threshold

Download (example_threshold.rs)

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use std::{error::Error, io, thread};
use tinkerforge::{barometer_bricklet::*, ip_connection::IpConnection};

const HOST: &str = "localhost";
const PORT: u16 = 4223;
const UID: &str = "XYZ"; // Change XYZ to the UID of your Barometer Bricklet.

fn main() -> Result<(), Box<dyn Error>> {
    let ipcon = IpConnection::new(); // Create IP connection.
    let b = BarometerBricklet::new(UID, &ipcon); // Create device object.

    ipcon.connect((HOST, PORT)).recv()??; // Connect to brickd.
                                          // Don't use device before ipcon is connected.

    // Get threshold receivers with a debounce time of 10 seconds (10000ms).
    b.set_debounce_period(10000);

    let air_pressure_reached_receiver = b.get_air_pressure_reached_callback_receiver();

    // Spawn thread to handle received callback messages.
    // This thread ends when the `b` object
    // is dropped, so there is no need for manual cleanup.
    thread::spawn(move || {
        for air_pressure_reached in air_pressure_reached_receiver {
            println!("Air Pressure: {} mbar", air_pressure_reached as f32 / 1000.0);
            println!("Enjoy the potentially good weather!");
        }
    });

    // Configure threshold for air pressure "greater than 1025 mbar".
    b.set_air_pressure_callback_threshold('>', 1025 * 1000, 0);

    println!("Press enter to exit.");
    let mut _input = String::new();
    io::stdin().read_line(&mut _input)?;
    ipcon.disconnect();
    Ok(())
}

API

To allow non-blocking usage, nearly every function of the Rust bindings returns a wrapper around a mpsc::Receiver. To block until the function has finished and get your result, call one of the receiver's recv variants. Those return either the result sent by the device, or any error occured.

Functions returning a result directly will block until the device has finished processing the request.

All functions listed below are thread-safe, those which return a receiver are lock-free.

Basic Functions

pub fn BarometerBricklet::new(uid: &str, ip_connection: &IpConnection) → BarometerBricklet

Creates a new BarometerBricklet object with the unique device ID uid and adds it to the IPConnection ipcon:

This device object can be used after the IP connection has been connected (see examples above).

pub fn BarometerBricklet::get_air_pressure(&self) → ConvertingReceiver<i32>

Returns the air pressure of the air pressure sensor. The value has a range of 10000 to 1200000 and is given in mbar/1000, i.e. a value of 1001092 means that an air pressure of 1001.092 mbar is measured.

If you want to get the air pressure periodically, it is recommended to use the BarometerBricklet::get_air_pressure_callback_receiver callback and set the period with BarometerBricklet::set_air_pressure_callback_period.

pub fn BarometerBricklet::get_altitude(&self) → ConvertingReceiver<i32>

Returns the relative altitude of the air pressure sensor. The value is given in cm and is calculated based on the difference between the current air pressure and the reference air pressure that can be set with BarometerBricklet::set_reference_air_pressure.

If you want to get the altitude periodically, it is recommended to use the BarometerBricklet::get_altitude_callback_receiver callback and set the period with BarometerBricklet::set_altitude_callback_period.

pub fn BarometerBricklet::set_reference_air_pressure(&self, air_pressure: i32) → ConvertingReceiver<()>

Sets the reference air pressure in mbar/1000 for the altitude calculation. Valid values are between 10000 and 1200000. Setting the reference to the current air pressure results in a calculated altitude of 0cm. 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.

The default value is 1013.25mbar.

pub fn BarometerBricklet::get_reference_air_pressure(&self) → ConvertingReceiver<i32>

Returns the reference air pressure as set by BarometerBricklet::set_reference_air_pressure.

Advanced Functions

pub fn BarometerBricklet::get_chip_temperature(&self) → ConvertingReceiver<i16>

Returns the temperature of the air pressure sensor. The value has a range of -4000 to 8500 and is given in °C/100, i.e. a value of 2007 means that a temperature of 20.07 °C is measured.

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 or the Temperature IR Bricklet.

pub fn BarometerBricklet::set_averaging(&self, moving_average_pressure: u8, average_pressure: u8, average_temperature: u8) → ConvertingReceiver<()>

Sets the different averaging parameters. It is possible to set the length of a normal averaging for the temperature and pressure, as well as an additional length of a moving average for the pressure. The moving average is calculated from the normal averages. There is no moving average for the temperature.

The maximum length for the pressure average is 10, for the temperature average is 255 and for the moving average is 25.

Setting the all three parameters to 0 will turn the averaging completely off. If the averaging is off, there is lots of noise on the data, but the data is without delay. Thus we recommend to turn the averaging off if the Barometer Bricklet data is to be used for sensor fusion with other sensors.

The default values are 10 for the normal averages and 25 for the moving average.

New in version 2.0.1 (Plugin).

pub fn BarometerBricklet::get_averaging(&self) → ConvertingReceiver<Averaging>

Returns the averaging configuration as set by BarometerBricklet::set_averaging.

New in version 2.0.1 (Plugin).

pub fn BarometerBricklet::get_api_version(&self) → [u8; 3]

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.

pub fn BarometerBricklet::get_response_expected(&mut self, function_id: u8) → 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 BarometerBricklet::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 BarometerBricklet::set_response_expected for the list of function ID constants available for this function.

pub fn BarometerBricklet::set_response_expected(&mut self, function_id: u8, response_expected: bool) → ()

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:

  • BAROMETER_BRICKLET_FUNCTION_SET_AIR_PRESSURE_CALLBACK_PERIOD = 3
  • BAROMETER_BRICKLET_FUNCTION_SET_ALTITUDE_CALLBACK_PERIOD = 5
  • BAROMETER_BRICKLET_FUNCTION_SET_AIR_PRESSURE_CALLBACK_THRESHOLD = 7
  • BAROMETER_BRICKLET_FUNCTION_SET_ALTITUDE_CALLBACK_THRESHOLD = 9
  • BAROMETER_BRICKLET_FUNCTION_SET_DEBOUNCE_PERIOD = 11
  • BAROMETER_BRICKLET_FUNCTION_SET_REFERENCE_AIR_PRESSURE = 13
  • BAROMETER_BRICKLET_FUNCTION_SET_AVERAGING = 20
pub fn BarometerBricklet::set_response_expected_all(&mut self, response_expected: bool) → ()

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

pub fn BarometerBricklet::get_identity(&self) → ConvertingReceiver<Identity>

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

pub fn BarometerBricklet::set_air_pressure_callback_period(&self, period: u32) → ConvertingReceiver<()>

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

The BarometerBricklet::get_air_pressure_callback_receiver callback is only triggered if the air pressure has changed since the last triggering.

The default value is 0.

pub fn BarometerBricklet::get_air_pressure_callback_period(&self) → ConvertingReceiver<u32>

Returns the period as set by BarometerBricklet::set_air_pressure_callback_period.

pub fn BarometerBricklet::set_altitude_callback_period(&self, period: u32) → ConvertingReceiver<()>

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

The BarometerBricklet::get_altitude_callback_receiver callback is only triggered if the altitude has changed since the last triggering.

The default value is 0.

pub fn BarometerBricklet::get_altitude_callback_period(&self) → ConvertingReceiver<u32>

Returns the period as set by BarometerBricklet::set_altitude_callback_period.

pub fn BarometerBricklet::set_air_pressure_callback_threshold(&self, option: char, min: i32, max: i32) → ConvertingReceiver<()>

Sets the thresholds for the BarometerBricklet::get_air_pressure_reached_callback_receiver callback.

The following options are possible:

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

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

The following constants are available for this function:

  • BAROMETER_BRICKLET_THRESHOLD_OPTION_OFF = 'x'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_INSIDE = 'i'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_SMALLER = '<'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_GREATER = '>'
pub fn BarometerBricklet::get_air_pressure_callback_threshold(&self) → ConvertingReceiver<AirPressureCallbackThreshold>

Returns the threshold as set by BarometerBricklet::set_air_pressure_callback_threshold.

The following constants are available for this function:

  • BAROMETER_BRICKLET_THRESHOLD_OPTION_OFF = 'x'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_INSIDE = 'i'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_SMALLER = '<'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_GREATER = '>'
pub fn BarometerBricklet::set_altitude_callback_threshold(&self, option: char, min: i32, max: i32) → ConvertingReceiver<()>

Sets the thresholds for the BarometerBricklet::get_altitude_reached_callback_receiver callback.

The following options are possible:

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

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

The following constants are available for this function:

  • BAROMETER_BRICKLET_THRESHOLD_OPTION_OFF = 'x'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_INSIDE = 'i'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_SMALLER = '<'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_GREATER = '>'
pub fn BarometerBricklet::get_altitude_callback_threshold(&self) → ConvertingReceiver<AltitudeCallbackThreshold>

Returns the threshold as set by BarometerBricklet::set_altitude_callback_threshold.

The following constants are available for this function:

  • BAROMETER_BRICKLET_THRESHOLD_OPTION_OFF = 'x'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_INSIDE = 'i'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_SMALLER = '<'
  • BAROMETER_BRICKLET_THRESHOLD_OPTION_GREATER = '>'
pub fn BarometerBricklet::set_debounce_period(&self, debounce: u32) → ConvertingReceiver<()>

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

pub fn BarometerBricklet::get_debounce_period(&self) → ConvertingReceiver<u32>

Returns the debounce period as set by BarometerBricklet::set_debounce_period.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding get_*_callback_receiver function, which returns a receiver for callback events.

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.

pub fn BarometerBricklet::get_air_pressure_callback_receiver(&self) → ConvertingCallbackReceiver<i32>

Receivers created with this function receive Air Pressure events.

This callback is triggered periodically with the period that is set by BarometerBricklet::set_air_pressure_callback_period. The received variable is the air pressure of the air pressure sensor.

The BarometerBricklet::get_air_pressure_callback_receiver callback is only triggered if the air pressure has changed since the last triggering.

pub fn BarometerBricklet::get_altitude_callback_receiver(&self) → ConvertingCallbackReceiver<i32>

Receivers created with this function receive Altitude events.

This callback is triggered periodically with the period that is set by BarometerBricklet::set_altitude_callback_period. The received variable is the altitude of the air pressure sensor.

The BarometerBricklet::get_altitude_callback_receiver callback is only triggered if the altitude has changed since the last triggering.

pub fn BarometerBricklet::get_air_pressure_reached_callback_receiver(&self) → ConvertingCallbackReceiver<i32>

Receivers created with this function receive Air Pressure Reached events.

This callback is triggered when the threshold as set by BarometerBricklet::set_air_pressure_callback_threshold is reached. The received variable is the air pressure of the air pressure sensor.

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

pub fn BarometerBricklet::get_altitude_reached_callback_receiver(&self) → ConvertingCallbackReceiver<i32>

Receivers created with this function receive Altitude Reached events.

This callback is triggered when the threshold as set by BarometerBricklet::set_altitude_callback_threshold is reached. The received variable is the altitude of the air pressure sensor.

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

Constants

BarometerBricklet::DEVICE_IDENTIFIER

This constant is used to identify a Barometer Bricklet.

The BarometerBricklet::get_identity function and the IpConnection::get_enumerate_callback_receiver callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

BarometerBricklet::DEVICE_DISPLAY_NAME

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