This is the description of the C/C++ API bindings for the Distance IR Bricklet. General information and technical specifications for the Distance IR 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_distance_ir.h"
#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your Distance IR Bricklet
int main(void) {
// Create IP connection
IPConnection ipcon;
ipcon_create(&ipcon);
// Create device object
DistanceIR dir;
distance_ir_create(&dir, 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 distance
uint16_t distance;
if(distance_ir_get_distance(&dir, &distance) < 0) {
fprintf(stderr, "Could not get distance, probably timeout\n");
return 1;
}
printf("Distance: %f cm\n", distance/10.0);
printf("Press key to exit\n");
getchar();
distance_ir_destroy(&dir);
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_distance_ir.h"
#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your Distance IR Bricklet
// Callback function for distance callback
void cb_distance(uint16_t distance, void *user_data) {
(void)user_data; // avoid unused parameter warning
printf("Distance: %f cm\n", distance/10.0);
}
int main(void) {
// Create IP connection
IPConnection ipcon;
ipcon_create(&ipcon);
// Create device object
DistanceIR dir;
distance_ir_create(&dir, 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 distance callback to function cb_distance
distance_ir_register_callback(&dir,
DISTANCE_IR_CALLBACK_DISTANCE,
(void (*)(void))cb_distance,
NULL);
// Set period for distance callback to 0.2s (200ms)
// Note: The distance callback is only called every 0.2 seconds
// if the distance has changed since the last call!
distance_ir_set_distance_callback_period(&dir, 200);
printf("Press key to exit\n");
getchar();
distance_ir_destroy(&dir);
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 | #include <stdio.h>
#include "ip_connection.h"
#include "bricklet_distance_ir.h"
#define HOST "localhost"
#define PORT 4223
#define UID "XYZ" // Change XYZ to the UID of your Distance IR Bricklet
// Callback function for distance reached callback
void cb_distance_reached(uint16_t distance, void *user_data) {
(void)user_data; // avoid unused parameter warning
printf("Distance: %f cm\n", distance/10.0);
}
int main(void) {
// Create IP connection
IPConnection ipcon;
ipcon_create(&ipcon);
// Create device object
DistanceIR dir;
distance_ir_create(&dir, 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)
distance_ir_set_debounce_period(&dir, 10000);
// Register distance reached callback to function cb_distance_reached
distance_ir_register_callback(&dir,
DISTANCE_IR_CALLBACK_DISTANCE_REACHED,
(void (*)(void))cb_distance_reached,
NULL);
// Configure threshold for distance "smaller than 30 cm"
distance_ir_set_distance_callback_threshold(&dir, '<', 30*10, 0);
printf("Press key to exit\n");
getchar();
distance_ir_destroy(&dir);
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.
distance_ir_create
(DistanceIR *distance_ir, const char *uid, IPConnection *ipcon)¶Parameters: |
|
---|
Creates the device object distance_ir
with the unique device ID uid
and adds
it to the IPConnection ipcon
:
DistanceIR distance_ir;
distance_ir_create(&distance_ir, "YOUR_DEVICE_UID", &ipcon);
This device object can be used after the IP connection has been connected.
distance_ir_destroy
(DistanceIR *distance_ir)¶Parameters: |
|
---|
Removes the device object distance_ir
from its IPConnection and destroys it.
The device object cannot be used anymore afterwards.
distance_ir_get_distance
(DistanceIR *distance_ir, uint16_t *ret_distance)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the distance measured by the sensor. Possible distance ranges are 40 to 300, 100 to 800 and 200 to 1500, depending on the selected IR sensor.
If you want to get the distance periodically, it is recommended to use the
DISTANCE_IR_CALLBACK_DISTANCE
callback and set the period with
distance_ir_set_distance_callback_period()
.
distance_ir_get_analog_value
(DistanceIR *distance_ir, 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 distance_ir_get_distance()
is averaged over several samples
to yield less noise, while distance_ir_get_analog_value()
gives back raw
unfiltered analog values. The only reason to use distance_ir_get_analog_value()
is,
if you need the full resolution of the analog-to-digital converter.
If you want the analog value periodically, it is recommended to use the
DISTANCE_IR_CALLBACK_ANALOG_VALUE
callback and set the period with
distance_ir_set_analog_value_callback_period()
.
distance_ir_set_sampling_point
(DistanceIR *distance_ir, uint8_t position, uint16_t distance)¶Parameters: |
|
---|---|
Returns: |
|
Sets a sampling point value to a specific position of the lookup table. The lookup table comprises 128 equidistant analog values with corresponding distances.
If you measure a distance of 50cm at the analog value 2048, you should call this function with (64, 5000). The utilized analog-to-digital converter has a resolution of 12 bit. With 128 sampling points on the whole range, this means that every sampling point has a size of 32 analog values. Thus the analog value 2048 has the corresponding sampling point 64 = 2048/32.
Sampling points are saved on the EEPROM of the Distance IR Bricklet and loaded again on startup.
Note
An easy way to calibrate the sampling points of the Distance IR Bricklet is implemented in the Brick Viewer. If you want to calibrate your Bricklet it is highly recommended to use this implementation.
distance_ir_get_sampling_point
(DistanceIR *distance_ir, uint8_t position, uint16_t *ret_distance)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the distance to a sampling point position as set by
distance_ir_set_sampling_point()
.
distance_ir_get_identity
(DistanceIR *distance_ir, 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.
distance_ir_register_callback
(DistanceIR *distance_ir, 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.
distance_ir_set_distance_callback_period
(DistanceIR *distance_ir, uint32_t period)¶Parameters: |
|
---|---|
Returns: |
|
Sets the period with which the DISTANCE_IR_CALLBACK_DISTANCE
callback is triggered
periodically. A value of 0 turns the callback off.
The DISTANCE_IR_CALLBACK_DISTANCE
callback is only triggered if the distance has changed since the
last triggering.
distance_ir_get_distance_callback_period
(DistanceIR *distance_ir, uint32_t *ret_period)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the period as set by distance_ir_set_distance_callback_period()
.
distance_ir_set_analog_value_callback_period
(DistanceIR *distance_ir, uint32_t period)¶Parameters: |
|
---|---|
Returns: |
|
Sets the period with which the DISTANCE_IR_CALLBACK_ANALOG_VALUE
callback is triggered
periodically. A value of 0 turns the callback off.
The DISTANCE_IR_CALLBACK_ANALOG_VALUE
callback is only triggered if the analog value has
changed since the last triggering.
distance_ir_get_analog_value_callback_period
(DistanceIR *distance_ir, uint32_t *ret_period)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the period as set by distance_ir_set_analog_value_callback_period()
.
distance_ir_set_distance_callback_threshold
(DistanceIR *distance_ir, char option, uint16_t min, uint16_t max)¶Parameters: |
|
---|---|
Returns: |
|
Sets the thresholds for the DISTANCE_IR_CALLBACK_DISTANCE_REACHED
callback.
The following options are possible:
Option | Description |
---|---|
'x' | Callback is turned off |
'o' | Callback is triggered when the distance is outside the min and max values |
'i' | Callback is triggered when the distance is inside the min and max values |
'<' | Callback is triggered when the distance is smaller than the min value (max is ignored) |
'>' | Callback is triggered when the distance is greater than the min value (max is ignored) |
The following constants are available for this function:
For option:
distance_ir_get_distance_callback_threshold
(DistanceIR *distance_ir, char *ret_option, uint16_t *ret_min, uint16_t *ret_max)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the threshold as set by distance_ir_set_distance_callback_threshold()
.
The following constants are available for this function:
For ret_option:
distance_ir_set_analog_value_callback_threshold
(DistanceIR *distance_ir, char option, uint16_t min, uint16_t max)¶Parameters: |
|
---|---|
Returns: |
|
Sets the thresholds for the DISTANCE_IR_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:
distance_ir_get_analog_value_callback_threshold
(DistanceIR *distance_ir, char *ret_option, uint16_t *ret_min, uint16_t *ret_max)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the threshold as set by distance_ir_set_analog_value_callback_threshold()
.
The following constants are available for this function:
For ret_option:
distance_ir_set_debounce_period
(DistanceIR *distance_ir, uint32_t debounce)¶Parameters: |
|
---|---|
Returns: |
|
Sets the period with which the threshold callbacks
are triggered, if the thresholds
keep being reached.
distance_ir_get_debounce_period
(DistanceIR *distance_ir, uint32_t *ret_debounce)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns: |
|
Returns the debounce period as set by distance_ir_set_debounce_period()
.
Callbacks can be registered to receive time critical or recurring data from the
device. The registration is done with the distance_ir_register_callback()
function:
void my_callback(int value, void *user_data) { printf("Value: %d\n", value); } distance_ir_register_callback(&distance_ir, DISTANCE_IR_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.
DISTANCE_IR_CALLBACK_DISTANCE
¶void callback(uint16_t distance, void *user_data)
Callback Parameters: |
|
---|
This callback is triggered periodically with the period that is set by
distance_ir_set_distance_callback_period()
. The parameter is the distance of the
sensor.
The DISTANCE_IR_CALLBACK_DISTANCE
callback is only triggered if the distance has changed since the
last triggering.
DISTANCE_IR_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
distance_ir_set_analog_value_callback_period()
. The parameter is the analog value of the
sensor.
The DISTANCE_IR_CALLBACK_ANALOG_VALUE
callback is only triggered if the analog value has changed
since the last triggering.
DISTANCE_IR_CALLBACK_DISTANCE_REACHED
¶void callback(uint16_t distance, void *user_data)
Callback Parameters: |
|
---|
This callback is triggered when the threshold as set by
distance_ir_set_distance_callback_threshold()
is reached.
The parameter is the distance of the sensor.
If the threshold keeps being reached, the callback is triggered periodically
with the period as set by distance_ir_set_debounce_period()
.
DISTANCE_IR_CALLBACK_ANALOG_VALUE_REACHED
¶void callback(uint16_t value, void *user_data)
Callback Parameters: |
|
---|
This callback is triggered when the threshold as set by
distance_ir_set_analog_value_callback_threshold()
is reached.
The parameter is the analog value of the sensor.
If the threshold keeps being reached, the callback is triggered periodically
with the period as set by distance_ir_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.
distance_ir_get_api_version
(DistanceIR *distance_ir, 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.
distance_ir_get_response_expected
(DistanceIR *distance_ir, 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
distance_ir_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:
distance_ir_set_response_expected
(DistanceIR *distance_ir, 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:
distance_ir_set_response_expected_all
(DistanceIR *distance_ir, bool response_expected)¶Parameters: |
|
---|---|
Returns: |
|
Changes the response expected flag for all setter and callback configuration functions of this device at once.
DISTANCE_IR_DEVICE_IDENTIFIER
¶This constant is used to identify a Distance IR Bricklet.
The distance_ir_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.
DISTANCE_IR_DEVICE_DISPLAY_NAME
¶This constant represents the human readable name of a Distance IR Bricklet.