This is the description of the MQTT 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 MQTT API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
1 2 3 4 5 6 | # Change XYZ to the UID of your CO2 Bricklet
setup:
# Get current CO2 concentration
subscribe to tinkerforge/response/co2_bricklet/XYZ/get_co2_concentration
publish '' to tinkerforge/request/co2_bricklet/XYZ/get_co2_concentration
|
Download (example-callback.txt)
1 2 3 4 5 6 7 8 9 10 11 | # Change XYZ to the UID of your CO2 Bricklet
setup:
# Handle incoming CO2 concentration callbacks
subscribe to tinkerforge/callback/co2_bricklet/XYZ/co2_concentration
publish '{"register": true}' to tinkerforge/register/co2_bricklet/XYZ/co2_concentration # Register co2_concentration callback
# 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!
publish '{"period": 1000}' to tinkerforge/request/co2_bricklet/XYZ/set_co2_concentration_callback_period
|
Download (example-threshold.txt)
1 2 3 4 5 6 7 8 9 10 11 12 | # Change XYZ to the UID of your CO2 Bricklet
setup:
# Get threshold callbacks with a debounce time of 10 seconds (10000ms)
publish '{"debounce": 10000}' to tinkerforge/request/co2_bricklet/XYZ/set_debounce_period
# Handle incoming CO2 concentration reached callbacks
subscribe to tinkerforge/callback/co2_bricklet/XYZ/co2_concentration_reached
publish '{"register": true}' to tinkerforge/register/co2_bricklet/XYZ/co2_concentration_reached # Register co2_concentration_reached callback
# Configure threshold for CO2 concentration "greater than 750 ppm"
publish '{"option": "greater", "min": 750, "max": 0}' to tinkerforge/request/co2_bricklet/XYZ/set_co2_concentration_callback_threshold
|
All published payloads to and from the MQTT bindings are in JSON format.
If an error occures, the bindings publish a JSON object containing the error message as member _ERROR
.
It is published on the corresponding response topic: .../response/...
for .../request/...
and .../callback/...
for .../register/...
.
request/
co2_bricklet/
<UID>/
get_co2_concentration
¶Request: |
|
---|---|
Response: |
|
Returns the measured CO2 concentration.
If you want to get the CO2 concentration periodically, it is recommended to use
the register/co2_bricklet/<UID>/co2_concentration
callback and set the period with
request/co2_bricklet/<UID>/set_co2_concentration_callback_period
.
request/
co2_bricklet/
<UID>/
get_identity
¶Request: |
|
---|---|
Response: |
|
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. If symbolic output is not disabled, the device identifier is mapped to the corresponding name in the format used in topics.
The display name contains the CO2's name in a human readable form.
request/
co2_bricklet/
<UID>/
set_co2_concentration_callback_period
¶Request: |
|
---|---|
Response: |
|
Sets the period with which the register/co2_bricklet/<UID>/co2_concentration
callback is
triggered periodically. A value of 0 turns the callback off.
The register/co2_bricklet/<UID>/co2_concentration
callback is only triggered if the CO2 concentration
has changed since the last triggering.
request/
co2_bricklet/
<UID>/
get_co2_concentration_callback_period
¶Request: |
|
---|---|
Response: |
|
Returns the period as set by request/co2_bricklet/<UID>/set_co2_concentration_callback_period
.
request/
co2_bricklet/
<UID>/
set_co2_concentration_callback_threshold
¶Request: |
|
---|---|
Response: |
|
Sets the thresholds for the register/co2_bricklet/<UID>/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 symbols are available for this function:
For option:
request/
co2_bricklet/
<UID>/
get_co2_concentration_callback_threshold
¶Request: |
|
---|---|
Response: |
|
Returns the threshold as set by request/co2_bricklet/<UID>/set_co2_concentration_callback_threshold
.
The following symbols are available for this function:
For option:
request/
co2_bricklet/
<UID>/
set_debounce_period
¶Request: |
|
---|---|
Response: |
|
Sets the period with which the threshold callbacks
are triggered, if the thresholds
keep being reached.
request/
co2_bricklet/
<UID>/
get_debounce_period
¶Request: |
|
---|---|
Response: |
|
Returns the debounce period as set by request/co2_bricklet/<UID>/set_debounce_period
.
Callbacks can be registered to receive
time critical or recurring data from the device. The registration is done
with the corresponding .../register/...
topic and an optional suffix.
This suffix can be used to deregister the callback later.
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.
register/
co2_bricklet/
<UID>/
co2_concentration
¶Register Request: |
|
---|---|
Callback Response: |
|
A callback can be registered for this event by publishing to the .../register/co2_bricklet/<UID>/co2_concentration[/<SUFFIX>]
topic with the payload "true".
An added callback can be removed by publishing to the same topic with the payload "false".
To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.
If the callback is triggered, a message with it's payload is published under the corresponding .../callback/co2_bricklet/<UID>/co2_concentration[/<SUFFIX>]
topic for each registered suffix.
This callback is triggered periodically with the period that is set by
request/co2_bricklet/<UID>/set_co2_concentration_callback_period
. The callback payload is the CO2
concentration of the sensor.
The register/co2_bricklet/<UID>/co2_concentration
callback is only triggered if the CO2 concentration
has changed since the last triggering.
register/
co2_bricklet/
<UID>/
co2_concentration_reached
¶Register Request: |
|
---|---|
Callback Response: |
|
A callback can be registered for this event by publishing to the .../register/co2_bricklet/<UID>/co2_concentration_reached[/<SUFFIX>]
topic with the payload "true".
An added callback can be removed by publishing to the same topic with the payload "false".
To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.
If the callback is triggered, a message with it's payload is published under the corresponding .../callback/co2_bricklet/<UID>/co2_concentration_reached[/<SUFFIX>]
topic for each registered suffix.
This callback is triggered when the threshold as set by
request/co2_bricklet/<UID>/set_co2_concentration_callback_threshold
is reached.
The callback payload is the CO2 concentration.
If the threshold keeps being reached, the callback is triggered periodically
with the period as set by request/co2_bricklet/<UID>/set_debounce_period
.