Software / API Bindings / MQTT / API Reference and Examples / Bricklets (Discontinued) / Moisture Bricklet

MQTT - Moisture Bricklet¶

This is the description of the MQTT API bindings for the Moisture Bricklet. General information and technical specifications for the Moisture Bricklet are summarized in its hardware description.

An installation guide for the MQTT API bindings is part of their general description.

Examples¶

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

Simple¶

Download (example-simple.txt)

# Change XYZ to the UID of your Moisture Bricklet

setup:
    # Get current moisture value
    subscribe to tinkerforge/response/moisture_bricklet/XYZ/get_moisture_value
    publish '' to tinkerforge/request/moisture_bricklet/XYZ/get_moisture_value

Callback¶

Download (example-callback.txt)

# Change XYZ to the UID of your Moisture Bricklet

setup:
    # Handle incoming moisture value callbacks
    subscribe to tinkerforge/callback/moisture_bricklet/XYZ/moisture
    publish '{"register": true}' to tinkerforge/register/moisture_bricklet/XYZ/moisture # Register moisture callback

    # Set period for moisture value callback to 1s (1000ms)
    # Note: The moisture value callback is only called every second
    #       if the moisture value has changed since the last call!
    publish '{"period": 1000}' to tinkerforge/request/moisture_bricklet/XYZ/set_moisture_callback_period

Threshold¶

Download (example-threshold.txt)

# Change XYZ to the UID of your Moisture Bricklet

setup:
    # Get threshold callbacks with a debounce time of 1 second (1000ms)
    publish '{"debounce": 1000}' to tinkerforge/request/moisture_bricklet/XYZ/set_debounce_period

    # Handle incoming moisture value reached callbacks
    subscribe to tinkerforge/callback/moisture_bricklet/XYZ/moisture_reached
    publish '{"register": true}' to tinkerforge/register/moisture_bricklet/XYZ/moisture_reached # Register moisture_reached callback

    # Configure threshold for moisture value "greater than 200"
    publish '{"option": "greater", "min": 200, "max": 0}' to tinkerforge/request/moisture_bricklet/XYZ/set_moisture_callback_threshold

API¶

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/....

Basic Functions¶

request/moisture_bricklet/<UID>/get_moisture_value¶

Request:	empty payload
Response:	moisture – Type: int, Range: [0 to 2¹² - 1]

Returns the current moisture value. A small value corresponds to little moisture, a big value corresponds to much moisture.

If you want to get the moisture value periodically, it is recommended to use the register/moisture_bricklet/<UID>/moisture callback and set the period with request/moisture_bricklet/<UID>/set_moisture_callback_period.

Advanced Functions¶

request/moisture_bricklet/<UID>/set_moving_average¶

Request:	average – Type: int, Range: [0 to 100], Default: 100
Response:	no response

Sets the length of a moving averaging for the moisture value.

Setting the length to 0 will turn the averaging completely off. With less averaging, there is more noise on the data.

request/moisture_bricklet/<UID>/get_moving_average¶

Request:	empty payload
Response:	average – Type: int, Range: [0 to 100], Default: 100

Returns the length moving average as set by request/moisture_bricklet/<UID>/set_moving_average.

request/moisture_bricklet/<UID>/get_identity¶

Request:

empty payload

Response:

uid – Type: string, Length: up to 8
connected_uid – Type: string, Length: up to 8
position – Type: char, Range: ["a" to "h", "z"]
hardware_version – Type: [int, ...], Length: 3

0: major – Type: int, Range: [0 to 255]
1: minor – Type: int, Range: [0 to 255]
2: revision – Type: int, Range: [0 to 255]

firmware_version – Type: [int, ...], Length: 3

0: major – Type: int, Range: [0 to 255]
1: minor – Type: int, Range: [0 to 255]
2: revision – Type: int, Range: [0 to 255]

device_identifier – Type: int, Range: [0 to 2¹⁶ - 1]
_display_name – Type: string

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 Moisture's name in a human readable form.

Callback Configuration Functions¶

request/moisture_bricklet/<UID>/set_moisture_callback_period¶

Request:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Response:	no response

Sets the period with which the register/moisture_bricklet/<UID>/moisture callback is triggered periodically. A value of 0 turns the callback off.

The register/moisture_bricklet/<UID>/moisture callback is only triggered if the moisture value has changed since the last triggering.

request/moisture_bricklet/<UID>/get_moisture_callback_period¶

Request:	empty payload
Response:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by request/moisture_bricklet/<UID>/set_moisture_callback_period.

request/moisture_bricklet/<UID>/set_moisture_callback_threshold¶

Request:	option – Type: char, Range: See symbols, Default: "x" min – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0 max – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0
Response:	no response

Sets the thresholds for the register/moisture_bricklet/<UID>/moisture_reached callback.

The following options are possible:

Option	Description
'x'	Callback is turned off
'o'	Callback is triggered when the moisture value is outside the min and max values
'i'	Callback is triggered when the moisture value is inside the min and max values
'<'	Callback is triggered when the moisture value is smaller than the min value (max is ignored)
'>'	Callback is triggered when the moisture value is greater than the min value (max is ignored)

The following symbols are available for this function:

For option:

"off" = "x"
"outside" = "o"
"inside" = "i"
"smaller" = "<"
"greater" = ">"

request/moisture_bricklet/<UID>/get_moisture_callback_threshold¶

Request:	empty payload
Response:	option – Type: char, Range: See symbols, Default: "x" min – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0 max – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0

Returns the threshold as set by request/moisture_bricklet/<UID>/set_moisture_callback_threshold.

The following symbols are available for this function:

For option:

"off" = "x"
"outside" = "o"
"inside" = "i"
"smaller" = "<"
"greater" = ">"

request/moisture_bricklet/<UID>/set_debounce_period¶

Request:	debounce – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100
Response:	no response

Sets the period with which the threshold callback

register/moisture_bricklet/<UID>/moisture_reached

is triggered, if the threshold

request/moisture_bricklet/<UID>/set_moisture_callback_threshold

keeps being reached.

request/moisture_bricklet/<UID>/get_debounce_period¶

Request:	empty payload
Response:	debounce – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100

Returns the debounce period as set by request/moisture_bricklet/<UID>/set_debounce_period.

Callbacks¶

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/moisture_bricklet/<UID>/moisture¶

Register Request:	register – Type: bool
Callback Response:	moisture – Type: int, Range: [0 to 2¹² - 1]

A callback can be registered for this event by publishing to the .../register/moisture_bricklet/<UID>/moisture[/<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/moisture_bricklet/<UID>/moisture[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/moisture_bricklet/<UID>/set_moisture_callback_period. The callback payload is the moisture value of the sensor.

The register/moisture_bricklet/<UID>/moisture callback is only triggered if the moisture value has changed since the last triggering.

register/moisture_bricklet/<UID>/moisture_reached¶

Register Request:	register – Type: bool
Callback Response:	moisture – Type: int, Range: [0 to 2¹² - 1]

A callback can be registered for this event by publishing to the .../register/moisture_bricklet/<UID>/moisture_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/moisture_bricklet/<UID>/moisture_reached[/<SUFFIX>] topic for each registered suffix.

This callback is triggered when the threshold as set by request/moisture_bricklet/<UID>/set_moisture_callback_threshold is reached. The callback payload is the moisture value of the sensor.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by request/moisture_bricklet/<UID>/set_debounce_period.