C/C++ - Dust Detector Bricklet

This is the description of the C/C++ API bindings for the Dust Detector Bricklet. General information and technical specifications for the Dust Detector Bricklet are summarized in its hardware description.

An installation guide for the C/C++ API bindings is part of their general description.

Examples

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

Simple

Download (example_simple.c)

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#include <stdio.h>

#include "ip_connection.h"
#include "bricklet_dust_detector.h"

#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your Dust Detector Bricklet

int main(void) {
    // Create IP connection
    IPConnection ipcon;
    ipcon_create(&ipcon);

    // Create device object
    DustDetector dd;
    dust_detector_create(&dd, UID, &ipcon);

    // Connect to brickd
    if(ipcon_connect(&ipcon, HOST, PORT) < 0) {
        fprintf(stderr, "Could not connect\n");
        return 1;
    }
    // Don't use device before ipcon is connected

    // Get current dust density
    uint16_t dust_density;
    if(dust_detector_get_dust_density(&dd, &dust_density) < 0) {
        fprintf(stderr, "Could not get dust density, probably timeout\n");
        return 1;
    }

    printf("Dust Density: %u µg/m³\n", dust_density);

    printf("Press key to exit\n");
    getchar();
    dust_detector_destroy(&dd);
    ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
    return 0;
}

Callback

Download (example_callback.c)

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#include <stdio.h>

#include "ip_connection.h"
#include "bricklet_dust_detector.h"

#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your Dust Detector Bricklet

// Callback function for dust density callback
void cb_dust_density(uint16_t dust_density, void *user_data) {
    (void)user_data; // avoid unused parameter warning

    printf("Dust Density: %u µg/m³\n", dust_density);
}

int main(void) {
    // Create IP connection
    IPConnection ipcon;
    ipcon_create(&ipcon);

    // Create device object
    DustDetector dd;
    dust_detector_create(&dd, UID, &ipcon);

    // Connect to brickd
    if(ipcon_connect(&ipcon, HOST, PORT) < 0) {
        fprintf(stderr, "Could not connect\n");
        return 1;
    }
    // Don't use device before ipcon is connected

    // Register dust density callback to function cb_dust_density
    dust_detector_register_callback(&dd,
                                    DUST_DETECTOR_CALLBACK_DUST_DENSITY,
                                    (void *)cb_dust_density,
                                    NULL);

    // Set period for dust density callback to 1s (1000ms)
    // Note: The dust density callback is only called every second
    //       if the dust density has changed since the last call!
    dust_detector_set_dust_density_callback_period(&dd, 1000);

    printf("Press key to exit\n");
    getchar();
    dust_detector_destroy(&dd);
    ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
    return 0;
}

Threshold

Download (example_threshold.c)

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#include <stdio.h>

#include "ip_connection.h"
#include "bricklet_dust_detector.h"

#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your Dust Detector Bricklet

// Callback function for dust density reached callback
void cb_dust_density_reached(uint16_t dust_density, void *user_data) {
    (void)user_data; // avoid unused parameter warning

    printf("Dust Density: %u µg/m³\n", dust_density);
}

int main(void) {
    // Create IP connection
    IPConnection ipcon;
    ipcon_create(&ipcon);

    // Create device object
    DustDetector dd;
    dust_detector_create(&dd, UID, &ipcon);

    // Connect to brickd
    if(ipcon_connect(&ipcon, HOST, PORT) < 0) {
        fprintf(stderr, "Could not connect\n");
        return 1;
    }
    // Don't use device before ipcon is connected

    // Get threshold callbacks with a debounce time of 10 seconds (10000ms)
    dust_detector_set_debounce_period(&dd, 10000);

    // Register dust density reached callback to function cb_dust_density_reached
    dust_detector_register_callback(&dd,
                                    DUST_DETECTOR_CALLBACK_DUST_DENSITY_REACHED,
                                    (void *)cb_dust_density_reached,
                                    NULL);

    // Configure threshold for dust density "greater than 10 µg/m³"
    dust_detector_set_dust_density_callback_threshold(&dd, '>', 10, 0);

    printf("Press key to exit\n");
    getchar();
    dust_detector_destroy(&dd);
    ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
    return 0;
}

API

Every function of the C/C++ bindings returns an integer which describes an error code. Data returned from the device, when a getter is called, is handled via call by reference. These parameters are labeled with the ret_ prefix.

Possible error codes are:

  • E_OK = 0
  • E_TIMEOUT = -1
  • E_NO_STREAM_SOCKET = -2
  • E_HOSTNAME_INVALID = -3
  • E_NO_CONNECT = -4
  • E_NO_THREAD = -5
  • E_NOT_ADDED = -6 (unused since bindings version 2.0.0)
  • E_ALREADY_CONNECTED = -7
  • E_NOT_CONNECTED = -8
  • E_INVALID_PARAMETER = -9
  • E_NOT_SUPPORTED = -10
  • E_UNKNOWN_ERROR_CODE = -11
  • E_STREAM_OUT_OF_SYNC = -12

as defined in ip_connection.h.

All functions listed below are thread-safe.

Basic Functions

void dust_detector_create(DustDetector *dust_detector, const char *uid, IPConnection *ipcon)

Creates the device object dust_detector with the unique device ID uid and adds it to the IPConnection ipcon:

DustDetector dust_detector;
dust_detector_create(&dust_detector, "YOUR_DEVICE_UID", &ipcon);

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

void dust_detector_destroy(DustDetector *dust_detector)

Removes the device object dust_detector from its IPConnection and destroys it. The device object cannot be used anymore afterwards.

int dust_detector_get_dust_density(DustDetector *dust_detector, uint16_t *ret_dust_density)

Returns the dust density in µg/m³.

If you want to get the dust density periodically, it is recommended to use the DUST_DETECTOR_CALLBACK_DUST_DENSITY callback and set the period with dust_detector_set_dust_density_callback_period().

Advanced Functions

int dust_detector_set_moving_average(DustDetector *dust_detector, uint8_t average)

Sets the length of a moving averaging for the dust_density.

Setting the length to 0 will turn the averaging completely off. With less averaging, there is more noise on the data.

The range for the averaging is 0-100.

The default value is 100.

int dust_detector_get_moving_average(DustDetector *dust_detector, uint8_t *ret_average)

Returns the length moving average as set by dust_detector_set_moving_average().

int dust_detector_get_api_version(DustDetector *dust_detector, uint8_t ret_api_version[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.

int dust_detector_get_response_expected(DustDetector *dust_detector, uint8_t function_id, bool *ret_response_expected)

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 dust_detector_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 dust_detector_set_response_expected() for the list of function ID defines available for this function.

int dust_detector_set_response_expected(DustDetector *dust_detector, uint8_t function_id, bool response_expected)

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 defines are available for this function:

  • DUST_DETECTOR_FUNCTION_SET_DUST_DENSITY_CALLBACK_PERIOD = 2
  • DUST_DETECTOR_FUNCTION_SET_DUST_DENSITY_CALLBACK_THRESHOLD = 4
  • DUST_DETECTOR_FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • DUST_DETECTOR_FUNCTION_SET_MOVING_AVERAGE = 10
int dust_detector_set_response_expected_all(DustDetector *dust_detector, bool response_expected)

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

int dust_detector_get_identity(DustDetector *dust_detector, char ret_uid[8], char ret_connected_uid[8], char *ret_position, uint8_t ret_hardware_version[3], uint8_t ret_firmware_version[3], uint16_t *ret_device_identifier)

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

void dust_detector_register_callback(DustDetector *dust_detector, int16_t callback_id, void *function, void *user_data)

Registers the given function with the given callback_id. The user_data will be passed as the last parameter to the function.

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

int dust_detector_set_dust_density_callback_period(DustDetector *dust_detector, uint32_t period)

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

The DUST_DETECTOR_CALLBACK_DUST_DENSITY callback is only triggered if the dust density has changed since the last triggering.

The default value is 0.

int dust_detector_get_dust_density_callback_period(DustDetector *dust_detector, uint32_t *ret_period)

Returns the period as set by dust_detector_set_dust_density_callback_period().

int dust_detector_set_dust_density_callback_threshold(DustDetector *dust_detector, char option, uint16_t min, uint16_t max)

Sets the thresholds for the DUST_DETECTOR_CALLBACK_DUST_DENSITY_REACHED callback.

The following options are possible:

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

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

The following defines are available for this function:

  • DUST_DETECTOR_THRESHOLD_OPTION_OFF = 'x'
  • DUST_DETECTOR_THRESHOLD_OPTION_OUTSIDE = 'o'
  • DUST_DETECTOR_THRESHOLD_OPTION_INSIDE = 'i'
  • DUST_DETECTOR_THRESHOLD_OPTION_SMALLER = '<'
  • DUST_DETECTOR_THRESHOLD_OPTION_GREATER = '>'
int dust_detector_get_dust_density_callback_threshold(DustDetector *dust_detector, char *ret_option, uint16_t *ret_min, uint16_t *ret_max)

Returns the threshold as set by dust_detector_set_dust_density_callback_threshold().

The following defines are available for this function:

  • DUST_DETECTOR_THRESHOLD_OPTION_OFF = 'x'
  • DUST_DETECTOR_THRESHOLD_OPTION_OUTSIDE = 'o'
  • DUST_DETECTOR_THRESHOLD_OPTION_INSIDE = 'i'
  • DUST_DETECTOR_THRESHOLD_OPTION_SMALLER = '<'
  • DUST_DETECTOR_THRESHOLD_OPTION_GREATER = '>'
int dust_detector_set_debounce_period(DustDetector *dust_detector, uint32_t debounce)

Sets the period in ms with which the threshold callback

is triggered, if the threshold

keeps being reached.

The default value is 100.

int dust_detector_get_debounce_period(DustDetector *dust_detector, uint32_t *ret_debounce)

Returns the debounce period as set by dust_detector_set_debounce_period().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the dust_detector_register_callback() function. The parameters consist of the device object, the callback ID, the callback function and optional user data:

void my_callback(int p, void *user_data) {
    printf("parameter: %d\n", p);
}

dust_detector_register_callback(&dust_detector, DUST_DETECTOR_CALLBACK_EXAMPLE, (void *)my_callback, NULL);

The available constants with corresponding callback function signatures 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.

DUST_DETECTOR_CALLBACK_DUST_DENSITY
void callback(uint16_t dust_density, void *user_data)

This callback is triggered periodically with the period that is set by dust_detector_set_dust_density_callback_period(). The parameter is the dust density of the sensor.

Der DUST_DETECTOR_CALLBACK_DUST_DENSITY callback is only triggered if the dust density value has changed since the last triggering.

DUST_DETECTOR_CALLBACK_DUST_DENSITY_REACHED
void callback(uint16_t dust_density, void *user_data)

This callback is triggered when the threshold as set by dust_detector_set_dust_density_callback_threshold() is reached. The parameter is the dust density of the sensor.

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

Constants

DUST_DETECTOR_DEVICE_IDENTIFIER

This constant is used to identify a Dust Detector Bricklet.

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

DUST_DETECTOR_DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Dust Detector Bricklet.