This is the description of the C/C++ API bindings for the Ambient Light Bricklet. General information and technical specifications for the Ambient Light Bricklet are summarized in its hardware description.
An installation guide for the C/C++ 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 28 29 30 31 32 33 34 35 36 37 38 39 40 | #include <stdio.h>
#include "ip_connection.h"
#include "bricklet_ambient_light.h"
#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your Ambient Light Bricklet
int main(void) {
// Create IP connection
IPConnection ipcon;
ipcon_create(&ipcon);
// Create device object
AmbientLight al;
ambient_light_create(&al, 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 illuminance
uint16_t illuminance;
if(ambient_light_get_illuminance(&al, &illuminance) < 0) {
fprintf(stderr, "Could not get illuminance, probably timeout\n");
return 1;
}
printf("Illuminance: %f lx\n", illuminance/10.0);
printf("Press key to exit\n");
getchar();
ambient_light_destroy(&al);
ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
return 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 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 | #include <stdio.h>
#include "ip_connection.h"
#include "bricklet_ambient_light.h"
#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your Ambient Light Bricklet
// Callback function for illuminance callback
void cb_illuminance(uint16_t illuminance, void *user_data) {
(void)user_data; // avoid unused parameter warning
printf("Illuminance: %f lx\n", illuminance/10.0);
}
int main(void) {
// Create IP connection
IPConnection ipcon;
ipcon_create(&ipcon);
// Create device object
AmbientLight al;
ambient_light_create(&al, 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 illuminance callback to function cb_illuminance
ambient_light_register_callback(&al,
AMBIENT_LIGHT_CALLBACK_ILLUMINANCE,
(void (*)(void))cb_illuminance,
NULL);
// Set period for illuminance callback to 1s (1000ms)
// Note: The illuminance callback is only called every second
// if the illuminance has changed since the last call!
ambient_light_set_illuminance_callback_period(&al, 1000);
printf("Press key to exit\n");
getchar();
ambient_light_destroy(&al);
ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
return 0;
}
|
Download (example_threshold.c)
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 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 | #include <stdio.h>
#include "ip_connection.h"
#include "bricklet_ambient_light.h"
#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your Ambient Light Bricklet
// Callback function for illuminance reached callback
void cb_illuminance_reached(uint16_t illuminance, void *user_data) {
(void)user_data; // avoid unused parameter warning
printf("Illuminance: %f lx\n", illuminance/10.0);
printf("Too bright, close the curtains!\n");
}
int main(void) {
// Create IP connection
IPConnection ipcon;
ipcon_create(&ipcon);
// Create device object
AmbientLight al;
ambient_light_create(&al, 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)
ambient_light_set_debounce_period(&al, 10000);
// Register illuminance reached callback to function cb_illuminance_reached
ambient_light_register_callback(&al,
AMBIENT_LIGHT_CALLBACK_ILLUMINANCE_REACHED,
(void (*)(void))cb_illuminance_reached,
NULL);
// Configure threshold for illuminance "greater than 200 lx"
ambient_light_set_illuminance_callback_threshold(&al, '>', 200*10, 0);
printf("Press key to exit\n");
getchar();
ambient_light_destroy(&al);
ipcon_destroy(&ipcon); // Calls ipcon_disconnect internally
return 0;
}
|
Most functions of the C/C++ bindings return an error code (e_code
).
Data returned from the device, when a getter is called,
is handled via output parameters. These parameters are labeled with the
ret_
prefix.
Possible error codes are:
as defined in ip_connection.h
.
All functions listed below are thread-safe.
ambient_light_create
(AmbientLight *ambient_light, const char *uid, IPConnection *ipcon)¶Parameters: |
|
---|
Creates the device object ambient_light
with the unique device ID uid
and adds
it to the IPConnection ipcon
:
AmbientLight ambient_light;
ambient_light_create(&ambient_light, "YOUR_DEVICE_UID", &ipcon);
This device object can be used after the IP connection has been connected.
ambient_light_destroy
(AmbientLight *ambient_light)¶Parameters: |
|
---|
Removes the device object ambient_light
from its IPConnection and destroys it.
The device object cannot be used anymore afterwards.
ambient_light_get_illuminance
(AmbientLight *ambient_light, uint16_t *ret_illuminance)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the illuminance of the ambient light sensor.
If you want to get the illuminance periodically, it is recommended to use the
AMBIENT_LIGHT_CALLBACK_ILLUMINANCE
callback and set the period with
ambient_light_set_illuminance_callback_period()
.
ambient_light_get_analog_value
(AmbientLight *ambient_light, uint16_t *ret_value)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the value as read by a 12-bit analog-to-digital converter.
Note
The value returned by ambient_light_get_illuminance()
is averaged over several samples
to yield less noise, while ambient_light_get_analog_value()
gives back raw
unfiltered analog values. The only reason to use ambient_light_get_analog_value()
is,
if you need the full resolution of the analog-to-digital converter.
Also, the analog-to-digital converter covers three different ranges that are set dynamically depending on the light intensity. It is impossible to distinguish between these ranges with the analog value.
If you want the analog value periodically, it is recommended to use the
AMBIENT_LIGHT_CALLBACK_ANALOG_VALUE
callback and set the period with
ambient_light_set_analog_value_callback_period()
.
ambient_light_get_identity
(AmbientLight *ambient_light, 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)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
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.
ambient_light_register_callback
(AmbientLight *ambient_light, int16_t callback_id, void (*function)(void), void *user_data)¶Parameters: |
|
---|
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.
ambient_light_set_illuminance_callback_period
(AmbientLight *ambient_light, uint32_t period)¶Parameters: |
|
---|---|
Returns: |
|
Sets the period with which the AMBIENT_LIGHT_CALLBACK_ILLUMINANCE
callback is triggered
periodically. A value of 0 turns the callback off.
The AMBIENT_LIGHT_CALLBACK_ILLUMINANCE
callback is only triggered if the illuminance has changed
since the last triggering.
ambient_light_get_illuminance_callback_period
(AmbientLight *ambient_light, uint32_t *ret_period)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the period as set by ambient_light_set_illuminance_callback_period()
.
ambient_light_set_analog_value_callback_period
(AmbientLight *ambient_light, uint32_t period)¶Parameters: |
|
---|---|
Returns: |
|
Sets the period with which the AMBIENT_LIGHT_CALLBACK_ANALOG_VALUE
callback is triggered
periodically. A value of 0 turns the callback off.
The AMBIENT_LIGHT_CALLBACK_ANALOG_VALUE
callback is only triggered if the analog value has
changed since the last triggering.
ambient_light_get_analog_value_callback_period
(AmbientLight *ambient_light, uint32_t *ret_period)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the period as set by ambient_light_set_analog_value_callback_period()
.
ambient_light_set_illuminance_callback_threshold
(AmbientLight *ambient_light, char option, uint16_t min, uint16_t max)¶Parameters: |
|
---|---|
Returns: |
|
Sets the thresholds for the AMBIENT_LIGHT_CALLBACK_ILLUMINANCE_REACHED
callback.
The following options are possible:
Option | Description |
---|---|
'x' | Callback is turned off |
'o' | Callback is triggered when the illuminance is outside the min and max values |
'i' | Callback is triggered when the illuminance is inside the min and max values |
'<' | Callback is triggered when the illuminance is smaller than the min value (max is ignored) |
'>' | Callback is triggered when the illuminance is greater than the min value (max is ignored) |
The following constants are available for this function:
For option:
ambient_light_get_illuminance_callback_threshold
(AmbientLight *ambient_light, char *ret_option, uint16_t *ret_min, uint16_t *ret_max)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the threshold as set by ambient_light_set_illuminance_callback_threshold()
.
The following constants are available for this function:
For ret_option:
ambient_light_set_analog_value_callback_threshold
(AmbientLight *ambient_light, char option, uint16_t min, uint16_t max)¶Parameters: |
|
---|---|
Returns: |
|
Sets the thresholds for the AMBIENT_LIGHT_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 following constants are available for this function:
For option:
ambient_light_get_analog_value_callback_threshold
(AmbientLight *ambient_light, char *ret_option, uint16_t *ret_min, uint16_t *ret_max)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the threshold as set by ambient_light_set_analog_value_callback_threshold()
.
The following constants are available for this function:
For ret_option:
ambient_light_set_debounce_period
(AmbientLight *ambient_light, uint32_t debounce)¶Parameters: |
|
---|---|
Returns: |
|
Sets the period with which the threshold callbacks
are triggered, if the thresholds
ambient_light_set_illuminance_callback_threshold()
,ambient_light_set_analog_value_callback_threshold()
keep being reached.
ambient_light_get_debounce_period
(AmbientLight *ambient_light, uint32_t *ret_debounce)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the debounce period as set by ambient_light_set_debounce_period()
.
Callbacks can be registered to receive time critical or recurring data from the
device. The registration is done with the ambient_light_register_callback()
function:
void my_callback(int value, void *user_data) { printf("Value: %d\n", value); } ambient_light_register_callback(&ambient_light, AMBIENT_LIGHT_CALLBACK_EXAMPLE, (void (*)(void))my_callback, NULL);
The available constants with corresponding 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.
AMBIENT_LIGHT_CALLBACK_ILLUMINANCE
¶void callback(uint16_t illuminance, void *user_data)
Callback Parameters: |
|
---|
This callback is triggered periodically with the period that is set by
ambient_light_set_illuminance_callback_period()
. The parameter is the illuminance of the
ambient light sensor.
The AMBIENT_LIGHT_CALLBACK_ILLUMINANCE
callback is only triggered if the illuminance has changed
since the last triggering.
AMBIENT_LIGHT_CALLBACK_ANALOG_VALUE
¶void callback(uint16_t value, void *user_data)
Callback Parameters: |
|
---|
This callback is triggered periodically with the period that is set by
ambient_light_set_analog_value_callback_period()
. The parameter is the analog value of the
ambient light sensor.
The AMBIENT_LIGHT_CALLBACK_ANALOG_VALUE
callback is only triggered if the analog value has
changed since the last triggering.
AMBIENT_LIGHT_CALLBACK_ILLUMINANCE_REACHED
¶void callback(uint16_t illuminance, void *user_data)
Callback Parameters: |
|
---|
This callback is triggered when the threshold as set by
ambient_light_set_illuminance_callback_threshold()
is reached.
The parameter is the illuminance of the ambient light sensor.
If the threshold keeps being reached, the callback is triggered periodically
with the period as set by ambient_light_set_debounce_period()
.
AMBIENT_LIGHT_CALLBACK_ANALOG_VALUE_REACHED
¶void callback(uint16_t value, void *user_data)
Callback Parameters: |
|
---|
This callback is triggered when the threshold as set by
ambient_light_set_analog_value_callback_threshold()
is reached.
The parameter is the analog value of the ambient light sensor.
If the threshold keeps being reached, the callback is triggered periodically
with the period as set by ambient_light_set_debounce_period()
.
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.
ambient_light_get_api_version
(AmbientLight *ambient_light, uint8_t ret_api_version[3])¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
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.
ambient_light_get_response_expected
(AmbientLight *ambient_light, uint8_t function_id, bool *ret_response_expected)¶Parameters: |
|
---|---|
Output 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
ambient_light_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:
ambient_light_set_response_expected
(AmbientLight *ambient_light, uint8_t function_id, bool 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:
ambient_light_set_response_expected_all
(AmbientLight *ambient_light, bool response_expected)¶Parameters: |
|
---|---|
Returns: |
|
Changes the response expected flag for all setter and callback configuration functions of this device at once.
AMBIENT_LIGHT_DEVICE_IDENTIFIER
¶This constant is used to identify a Ambient Light Bricklet.
The ambient_light_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.
AMBIENT_LIGHT_DEVICE_DISPLAY_NAME
¶This constant represents the human readable name of a Ambient Light Bricklet.