Shell - CO2 Bricklet

This is the description of the Shell 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 Shell API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Simple

Download (example-simple.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your CO2 Bricklet

# Get current CO2 concentration
tinkerforge call co2-bricklet $uid get-co2-concentration

Callback

Download (example-callback.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your CO2 Bricklet

# Handle incoming CO2 concentration callbacks
tinkerforge dispatch co2-bricklet $uid 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!
tinkerforge call co2-bricklet $uid set-co2-concentration-callback-period 1000

echo "Press key to exit"; read dummy

kill -- -$$ # Stop callback dispatch in background

Threshold

Download (example-threshold.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your CO2 Bricklet

# Get threshold callbacks with a debounce time of 10 seconds (10000ms)
tinkerforge call co2-bricklet $uid set-debounce-period 10000

# Handle incoming CO2 concentration reached callbacks
tinkerforge dispatch co2-bricklet $uid co2-concentration-reached &

# Configure threshold for CO2 concentration "greater than 750 ppm"
tinkerforge call co2-bricklet $uid set-co2-concentration-callback-threshold threshold-option-greater 750 0

echo "Press key to exit"; read dummy

kill -- -$$ # Stop callback dispatch in background

API

Possible exit codes for all tinkerforge commands are:

  • 1: interrupted (ctrl+c)
  • 2: syntax error
  • 21: Python 2.5 or newer is required
  • 22: Python argparse module is missing
  • 23: socket error
  • 24: other exception
  • 25: invalid placeholder in format string
  • 26: authentication error
  • 201: timeout occurred
  • 209: invalid argument value
  • 210: function is not supported
  • 211: unknown error

Command Structure

The common options of the call and dispatch commands are documented here. The specific command structure is shown below.

tinkerforge call co2-bricklet [<option>..] <uid> <function> [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The call command is used to call a function of the CO2 Bricklet. It can take several options:

  • --help shows help for the specific call command and exits
  • --list-functions shows a list of known functions of the CO2 Bricklet and exits
tinkerforge dispatch co2-bricklet [<option>..] <uid> <callback>
Parameters:
  • <uid> -- string
  • <callback> -- string

The dispatch command is used to dispatch a callback of the CO2 Bricklet. It can take several options:

  • --help shows help for the specific dispatch command and exits
  • --list-callbacks shows a list of known callbacks of the CO2 Bricklet and exits
tinkerforge call co2-bricklet <uid> <function> [<option>..] [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The <function> to be called can take different options depending of its kind. All functions can take the following options:

  • --help shows help for the specific function and exits

Getter functions can take the following options:

  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Setter functions can take the following options:

  • --expect-response requests response and waits for it

The --expect-response option for setter functions allows to detect timeouts and other error conditions calls of setters as well. The device will then send a response for this purpose. If this option is not given for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

tinkerforge dispatch co2-bricklet <uid> <callback> [<option>..]
Parameters:
  • <uid> -- string
  • <callback> -- string

The <callback> to be dispatched can take several options:

  • --help shows help for the specific callback and exits
  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Basic Functions

tinkerforge call co2-bricklet <uid> get-co2-concentration
Output:
  • co2-concentration -- int

Returns the measured CO2 concentration. The value is in ppm (parts per million) and between 0 to 10000.

If you want to get the CO2 concentration periodically, it is recommended to use the co2-concentration callback and set the period with set-co2-concentration-callback-period.

Advanced Functions

tinkerforge call co2-bricklet <uid> get-identity
Output:
  • uid -- string
  • connected-uid -- string
  • position -- char
  • hardware-version -- int,int,int
  • firmware-version -- int,int,int
  • device-identifier -- int (has symbols)

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

Callback Configuration Functions

tinkerforge call co2-bricklet <uid> set-co2-concentration-callback-period <period>
Parameters:
  • <period> -- int
Output:

no output

Sets the period in ms with which the co2-concentration callback is triggered periodically. A value of 0 turns the callback off.

The co2-concentration callback is only triggered if the CO2 concentration has changed since the last triggering.

The default value is 0.

tinkerforge call co2-bricklet <uid> get-co2-concentration-callback-period
Output:
  • period -- int

Returns the period as set by set-co2-concentration-callback-period.

tinkerforge call co2-bricklet <uid> set-co2-concentration-callback-threshold <option> <min> <max>
Parameters:
  • <option> -- char (has symbols)
  • <min> -- int
  • <max> -- int
Output:

no output

Sets the thresholds for the 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 default value is ('x', 0, 0).

The following symbols are available for this function:

  • threshold-option-off = x, for <option>
  • threshold-option-outside = o, for <option>
  • threshold-option-inside = i, for <option>
  • threshold-option-smaller = <, for <option>
  • threshold-option-greater = >, for <option>
tinkerforge call co2-bricklet <uid> get-co2-concentration-callback-threshold
Output:
  • option -- char (has symbols)
  • min -- int
  • max -- int

Returns the threshold as set by set-co2-concentration-callback-threshold.

The following symbols are available for this function:

  • threshold-option-off = x, for option
  • threshold-option-outside = o, for option
  • threshold-option-inside = i, for option
  • threshold-option-smaller = <, for option
  • threshold-option-greater = >, for option
tinkerforge call co2-bricklet <uid> set-debounce-period <debounce>
Parameters:
  • <debounce> -- int
Output:

no output

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

tinkerforge call co2-bricklet <uid> get-debounce-period
Output:
  • debounce -- int

Returns the debounce period as set by set-debounce-period.

Callbacks

Callbacks can be used to receive time critical or recurring data from the device:

tinkerforge dispatch co2-bricklet <uid> example

The available callbacks 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.

tinkerforge dispatch co2-bricklet <uid> co2-concentration
Output:
  • co2-concentration -- int

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 co2-concentration callback is only triggered if the CO2 concentration has changed since the last triggering.

tinkerforge dispatch co2-bricklet <uid> co2-concentration-reached
Output:
  • co2-concentration -- int

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.