This is the description of the Perl API bindings for the CO2 Bricklet. General information and technical specifications for the CO2 Bricklet are summarized in its hardware description.
An installation guide for the Perl 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 | #!/usr/bin/perl
use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletCO2;
use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your CO2 Bricklet
my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $co2 = Tinkerforge::BrickletCO2->new(&UID, $ipcon); # Create device object
$ipcon->connect(&HOST, &PORT); # Connect to brickd
# Don't use device before ipcon is connected
# Get current CO2 concentration
my $co2_concentration = $co2->get_co2_concentration();
print "CO2 Concentration: $co2_concentration ppm\n";
print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();
|
Download (example_callback.pl)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | #!/usr/bin/perl
use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletCO2;
use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your CO2 Bricklet
# Callback subroutine for CO2 concentration callback
sub cb_co2_concentration
{
my ($co2_concentration) = @_;
print "CO2 Concentration: $co2_concentration ppm\n";
}
my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $co2 = Tinkerforge::BrickletCO2->new(&UID, $ipcon); # Create device object
$ipcon->connect(&HOST, &PORT); # Connect to brickd
# Don't use device before ipcon is connected
# Register CO2 concentration callback to subroutine cb_co2_concentration
$co2->register_callback($co2->CALLBACK_CO2_CONCENTRATION, 'cb_co2_concentration');
# Set period for CO2 concentration callback to 1s (1000ms)
# Note: The CO2 concentration callback is only called every second
# if the CO2 concentration has changed since the last call!
$co2->set_co2_concentration_callback_period(1000);
print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();
|
Download (example_threshold.pl)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 | #!/usr/bin/perl
use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletCO2;
use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your CO2 Bricklet
# Callback subroutine for CO2 concentration reached callback
sub cb_co2_concentration_reached
{
my ($co2_concentration) = @_;
print "CO2 Concentration: $co2_concentration ppm\n";
}
my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $co2 = Tinkerforge::BrickletCO2->new(&UID, $ipcon); # Create device object
$ipcon->connect(&HOST, &PORT); # Connect to brickd
# Don't use device before ipcon is connected
# Get threshold callbacks with a debounce time of 10 seconds (10000ms)
$co2->set_debounce_period(10000);
# Register CO2 concentration reached callback to subroutine cb_co2_concentration_reached
$co2->register_callback($co2->CALLBACK_CO2_CONCENTRATION_REACHED,
'cb_co2_concentration_reached');
# Configure threshold for CO2 concentration "greater than 750 ppm"
$co2->set_co2_concentration_callback_threshold('>', 750, 0);
print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();
|
Generally, every subroutine of the Perl bindings can report an error as
Tinkerforge::Error
object via croak()
. The object has a
get_code()
and a get_message()
subroutine. There are different
error code:
All functions listed below are thread-safe.
BrickletCO2
->
new
($uid, $ipcon)¶Parameters: |
|
---|---|
Returns: |
|
Creates an object with the unique device ID $uid
:
$co2 = BrickletCO2->new("YOUR_DEVICE_UID", $ipcon);
This object can then be used after the IP Connection is connected.
BrickletCO2
->
get_co2_concentration
()¶Returns: |
|
---|
Returns the measured CO2 concentration.
If you want to get the CO2 concentration periodically, it is recommended to use
the CALLBACK_CO2_CONCENTRATION
callback and set the period with
set_co2_concentration_callback_period()
.
BrickletCO2
->
get_identity
()¶Return Array: |
|
---|
Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.
The position can be 'a', 'b', 'c', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.
The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.
BrickletCO2
->
register_callback
($callback_id, $function)¶Parameters: |
|
---|---|
Returns: |
|
Registers the given $function
name with the given $callback_id
.
The available callback IDs with corresponding function signatures are listed below.
BrickletCO2
->
set_co2_concentration_callback_period
($period)¶Parameters: |
|
---|---|
Returns: |
|
Sets the period with which the CALLBACK_CO2_CONCENTRATION
callback is
triggered periodically. A value of 0 turns the callback off.
The CALLBACK_CO2_CONCENTRATION
callback is only triggered if the CO2 concentration
has changed since the last triggering.
BrickletCO2
->
get_co2_concentration_callback_period
()¶Returns: |
|
---|
Returns the period as set by set_co2_concentration_callback_period()
.
BrickletCO2
->
set_co2_concentration_callback_threshold
($option, $min, $max)¶Parameters: |
|
---|---|
Returns: |
|
Sets the thresholds for the CALLBACK_CO2_CONCENTRATION_REACHED
callback.
The following options are possible:
Option | Description |
---|---|
'x' | Callback is turned off |
'o' | Callback is triggered when the CO2 concentration is outside the min and max values |
'i' | Callback is triggered when the CO2 concentration is inside the min and max values |
'<' | Callback is triggered when the CO2 concentration is smaller than the min value (max is ignored) |
'>' | Callback is triggered when the CO2 concentration is greater than the min value (max is ignored) |
The following constants are available for this function:
For $option:
BrickletCO2
->
get_co2_concentration_callback_threshold
()¶Return Array: |
|
---|
Returns the threshold as set by set_co2_concentration_callback_threshold()
.
The following constants are available for this function:
For $option:
BrickletCO2
->
set_debounce_period
($debounce)¶Parameters: |
|
---|---|
Returns: |
|
Sets the period with which the threshold callbacks
are triggered, if the thresholds
keep being reached.
BrickletCO2
->
get_debounce_period
()¶Returns: |
|
---|
Returns the debounce period as set by set_debounce_period()
.
Callbacks can be registered to receive
time critical or recurring data from the device. The registration is done
with the register_callback()
function of
the device object. The first parameter is the callback ID and the second
parameter the callback function name:
sub my_callback
{
print "@_[0]";
}
$co2->register_callback(BrickletCO2->CALLBACK_EXAMPLE, 'my_callback')
The callback function will be called from an internal thread of the
IP Connection. In contrast to many other programming languages, variables are
not automatically shared between threads in Perl. If you want to share a global
variable between a callback function and the rest for your program it has to be
marked as :shared
. See the documentation of the threads::shared Perl module for more details.
The available constants with inherent number and type of parameters are described below.
Note
Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.
BrickletCO2
->
CALLBACK_CO2_CONCENTRATION
¶Callback Parameters: |
|
---|
This callback is triggered periodically with the period that is set by
set_co2_concentration_callback_period()
. The parameter is the CO2
concentration of the sensor.
The CALLBACK_CO2_CONCENTRATION
callback is only triggered if the CO2 concentration
has changed since the last triggering.
BrickletCO2
->
CALLBACK_CO2_CONCENTRATION_REACHED
¶Callback Parameters: |
|
---|
This callback is triggered when the threshold as set by
set_co2_concentration_callback_threshold()
is reached.
The parameter is the CO2 concentration.
If the threshold keeps being reached, the callback is triggered periodically
with the period as set by set_debounce_period()
.
Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.
BrickletCO2
->
get_api_version
()¶Return Array: |
|
---|
Returns the version of the API definition implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.
BrickletCO2
->
get_response_expected
($function_id)¶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
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 $function_id:
BrickletCO2
->
set_response_expected
($function_id, $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 $function_id:
BrickletCO2
->
set_response_expected_all
($response_expected)¶Parameters: |
|
---|---|
Returns: |
|
Changes the response expected flag for all setter and callback configuration functions of this device at once.
BrickletCO2
->
DEVICE_IDENTIFIER
¶This constant is used to identify a CO2 Bricklet.
The get_identity()
function and the
IPConnection->CALLBACK_ENUMERATE
callback of the IP Connection have a device_identifier
parameter to specify
the Brick's or Bricklet's type.
BrickletCO2
->
DEVICE_DISPLAY_NAME
¶This constant represents the human readable name of a CO2 Bricklet.