C/C++ - Color Bricklet

This is the description of the C/C++ API bindings for the Color Bricklet. General information and technical specifications for the Color 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_color.h"

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

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

    // Create device object
    Color c;
    color_create(&c, 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 color
    uint16_t r, g, b, c_;
    if(color_get_color(&c, &r, &g, &b, &c_) < 0) {
        fprintf(stderr, "Could not get color, probably timeout\n");
        return 1;
    }

    printf("Color [R]: %u\n", r);
    printf("Color [G]: %u\n", g);
    printf("Color [B]: %u\n", b);
    printf("Color [C]: %u\n", c_);

    printf("Press key to exit\n");
    getchar();
    color_destroy(&c);
    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_color.h"

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

// Callback function for color callback
void cb_color(uint16_t r, uint16_t g, uint16_t b, uint16_t c, void *user_data) {
    (void)user_data; // avoid unused parameter warning

    printf("Color [R]: %u\n", r);
    printf("Color [G]: %u\n", g);
    printf("Color [B]: %u\n", b);
    printf("Color [C]: %u\n", c);
    printf("\n");
}

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

    // Create device object
    Color c;
    color_create(&c, 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 color callback to function cb_color
    color_register_callback(&c,
                            COLOR_CALLBACK_COLOR,
                            (void *)cb_color,
                            NULL);

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

    printf("Press key to exit\n");
    getchar();
    color_destroy(&c);
    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_color.h"

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

// Callback function for color reached callback
void cb_color_reached(uint16_t r, uint16_t g, uint16_t b, uint16_t c, void *user_data) {
    (void)user_data; // avoid unused parameter warning

    printf("Color [R]: %u\n", r);
    printf("Color [G]: %u\n", g);
    printf("Color [B]: %u\n", b);
    printf("Color [C]: %u\n", c);
    printf("\n");
}

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

    // Create device object
    Color c;
    color_create(&c, 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)
    color_set_debounce_period(&c, 10000);

    // Register color reached callback to function cb_color_reached
    color_register_callback(&c,
                            COLOR_CALLBACK_COLOR_REACHED,
                            (void *)cb_color_reached,
                            NULL);

    // Configure threshold for color "greater than 100, 200, 300, 400"
    color_set_color_callback_threshold(&c, '>', 100, 0, 200, 0, 300, 0, 400, 0);

    printf("Press key to exit\n");
    getchar();
    color_destroy(&c);
    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 color_create(Color *color, const char *uid, IPConnection *ipcon)

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

Color color;
color_create(&color, "YOUR_DEVICE_UID", &ipcon);

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

void color_destroy(Color *color)

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

int color_get_color(Color *color, uint16_t *ret_r, uint16_t *ret_g, uint16_t *ret_b, uint16_t *ret_c)

Returns the measured color of the sensor. The values have a range of 0 to 65535.

The red (r), green (g), blue (b) and clear (c) colors are measured with four different photodiodes that are responsive at different wavelengths:

Chart Responsivity / Wavelength

If you want to get the color periodically, it is recommended to use the COLOR_CALLBACK_COLOR callback and set the period with color_set_color_callback_period().

int color_light_on(Color *color)

Turns the LED on.

int color_light_off(Color *color)

Turns the LED off.

int color_is_light_on(Color *color, uint8_t *ret_light)

Returns the state of the LED. Possible values are:

  • 0: On
  • 1: Off

The following defines are available for this function:

  • COLOR_LIGHT_ON = 0
  • COLOR_LIGHT_OFF = 1
int color_set_config(Color *color, uint8_t gain, uint8_t integration_time)

Sets the configuration of the sensor. Gain and integration time can be configured in this way.

For configuring the gain:

  • 0: 1x Gain
  • 1: 4x Gain
  • 2: 16x Gain
  • 3: 60x Gain

For configuring the integration time:

  • 0: 2.4ms
  • 1: 24ms
  • 2: 101ms
  • 3: 154ms
  • 4: 700ms

Increasing the gain enables the sensor to detect a color from a higher distance.

The integration time provides a trade-off between conversion time and accuracy. With a longer integration time the values read will be more accurate but it will take longer time to get the conversion results.

The default values are 60x gain and 154ms integration time.

The following defines are available for this function:

  • COLOR_GAIN_1X = 0
  • COLOR_GAIN_4X = 1
  • COLOR_GAIN_16X = 2
  • COLOR_GAIN_60X = 3
  • COLOR_INTEGRATION_TIME_2MS = 0
  • COLOR_INTEGRATION_TIME_24MS = 1
  • COLOR_INTEGRATION_TIME_101MS = 2
  • COLOR_INTEGRATION_TIME_154MS = 3
  • COLOR_INTEGRATION_TIME_700MS = 4
int color_get_config(Color *color, uint8_t *ret_gain, uint8_t *ret_integration_time)

Returns the configuration as set by color_set_config().

The following defines are available for this function:

  • COLOR_GAIN_1X = 0
  • COLOR_GAIN_4X = 1
  • COLOR_GAIN_16X = 2
  • COLOR_GAIN_60X = 3
  • COLOR_INTEGRATION_TIME_2MS = 0
  • COLOR_INTEGRATION_TIME_24MS = 1
  • COLOR_INTEGRATION_TIME_101MS = 2
  • COLOR_INTEGRATION_TIME_154MS = 3
  • COLOR_INTEGRATION_TIME_700MS = 4
int color_get_illuminance(Color *color, uint32_t *ret_illuminance)

Returns the illuminance affected by the gain and integration time as set by color_set_config(). To get the illuminance in Lux apply this formula:

lux = illuminance * 700 / gain / integration_time

To get a correct illuminance measurement make sure that the color values themself are not saturated. The color value (R, G or B) is saturated if it is equal to the maximum value of 65535. In that case you have to reduce the gain, see color_set_config().

int color_get_color_temperature(Color *color, uint16_t *ret_color_temperature)

Returns the color temperature in Kelvin.

To get a correct color temperature measurement make sure that the color values themself are not saturated. The color value (R, G or B) is saturated if it is equal to the maximum value of 65535. In that case you have to reduce the gain, see color_set_config().

Advanced Functions

int color_get_api_version(Color *color, 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 color_get_response_expected(Color *color, 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 color_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 color_set_response_expected() for the list of function ID defines available for this function.

int color_set_response_expected(Color *color, 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:

  • COLOR_FUNCTION_SET_COLOR_CALLBACK_PERIOD = 2
  • COLOR_FUNCTION_SET_COLOR_CALLBACK_THRESHOLD = 4
  • COLOR_FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • COLOR_FUNCTION_LIGHT_ON = 10
  • COLOR_FUNCTION_LIGHT_OFF = 11
  • COLOR_FUNCTION_SET_CONFIG = 13
  • COLOR_FUNCTION_SET_ILLUMINANCE_CALLBACK_PERIOD = 17
  • COLOR_FUNCTION_SET_COLOR_TEMPERATURE_CALLBACK_PERIOD = 19
int color_set_response_expected_all(Color *color, bool response_expected)

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

int color_get_identity(Color *color, 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 color_register_callback(Color *color, 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 color_set_color_callback_period(Color *color, uint32_t period)

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

The COLOR_CALLBACK_COLOR callback is only triggered if the color has changed since the last triggering.

The default value is 0.

int color_get_color_callback_period(Color *color, uint32_t *ret_period)

Returns the period as set by color_set_color_callback_period().

int color_set_color_callback_threshold(Color *color, char option, uint16_t min_r, uint16_t max_r, uint16_t min_g, uint16_t max_g, uint16_t min_b, uint16_t max_b, uint16_t min_c, uint16_t max_c)

Sets the thresholds for the COLOR_CALLBACK_COLOR_REACHED callback.

The following options are possible:

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

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

The following defines are available for this function:

  • COLOR_THRESHOLD_OPTION_OFF = 'x'
  • COLOR_THRESHOLD_OPTION_OUTSIDE = 'o'
  • COLOR_THRESHOLD_OPTION_INSIDE = 'i'
  • COLOR_THRESHOLD_OPTION_SMALLER = '<'
  • COLOR_THRESHOLD_OPTION_GREATER = '>'
int color_get_color_callback_threshold(Color *color, char *ret_option, uint16_t *ret_min_r, uint16_t *ret_max_r, uint16_t *ret_min_g, uint16_t *ret_max_g, uint16_t *ret_min_b, uint16_t *ret_max_b, uint16_t *ret_min_c, uint16_t *ret_max_c)

Returns the threshold as set by color_set_color_callback_threshold().

The following defines are available for this function:

  • COLOR_THRESHOLD_OPTION_OFF = 'x'
  • COLOR_THRESHOLD_OPTION_OUTSIDE = 'o'
  • COLOR_THRESHOLD_OPTION_INSIDE = 'i'
  • COLOR_THRESHOLD_OPTION_SMALLER = '<'
  • COLOR_THRESHOLD_OPTION_GREATER = '>'
int color_set_debounce_period(Color *color, 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 color_get_debounce_period(Color *color, uint32_t *ret_debounce)

Returns the debounce period as set by color_set_debounce_period().

int color_set_illuminance_callback_period(Color *color, uint32_t period)

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

The COLOR_CALLBACK_ILLUMINANCE callback is only triggered if the illuminance has changed since the last triggering.

The default value is 0.

int color_get_illuminance_callback_period(Color *color, uint32_t *ret_period)

Returns the period as set by color_set_illuminance_callback_period().

int color_set_color_temperature_callback_period(Color *color, uint32_t period)

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

The COLOR_CALLBACK_COLOR_TEMPERATURE callback is only triggered if the color temperature has changed since the last triggering.

The default value is 0.

int color_get_color_temperature_callback_period(Color *color, uint32_t *ret_period)

Returns the period as set by color_set_color_temperature_callback_period().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the color_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);
}

color_register_callback(&color, COLOR_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.

COLOR_CALLBACK_COLOR
void callback(uint16_t r, uint16_t g, uint16_t b, uint16_t c, void *user_data)

This callback is triggered periodically with the period that is set by color_set_color_callback_period(). The parameter is the color of the sensor as RGBC.

The COLOR_CALLBACK_COLOR callback is only triggered if the color has changed since the last triggering.

COLOR_CALLBACK_COLOR_REACHED
void callback(uint16_t r, uint16_t g, uint16_t b, uint16_t c, void *user_data)

This callback is triggered when the threshold as set by color_set_color_callback_threshold() is reached. The parameter is the color of the sensor as RGBC.

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

COLOR_CALLBACK_ILLUMINANCE
void callback(uint32_t illuminance, void *user_data)

This callback is triggered periodically with the period that is set by color_set_illuminance_callback_period(). The parameter is the illuminance. See color_get_illuminance() for how to interpret this value.

The COLOR_CALLBACK_ILLUMINANCE callback is only triggered if the illuminance has changed since the last triggering.

COLOR_CALLBACK_COLOR_TEMPERATURE
void callback(uint16_t color_temperature, void *user_data)

This callback is triggered periodically with the period that is set by color_set_color_temperature_callback_period(). The parameter is the color temperature in Kelvin.

The COLOR_CALLBACK_COLOR_TEMPERATURE callback is only triggered if the color temperature has changed since the last triggering.

Constants

COLOR_DEVICE_IDENTIFIER

This constant is used to identify a Color Bricklet.

The color_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.

COLOR_DEVICE_DISPLAY_NAME

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