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

MQTT - Accelerometer Bricklet¶

This is the description of the MQTT API bindings for the Accelerometer Bricklet. General information and technical specifications for the Accelerometer 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 Accelerometer Bricklet

setup:
    # Get current acceleration
    subscribe to tinkerforge/response/accelerometer_bricklet/XYZ/get_acceleration
    publish '' to tinkerforge/request/accelerometer_bricklet/XYZ/get_acceleration

Callback¶

Download (example-callback.txt)

# Change XYZ to the UID of your Accelerometer Bricklet

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

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

Threshold¶

Download (example-threshold.txt)

# Change XYZ to the UID of your Accelerometer Bricklet

setup:
    # Get threshold callbacks with a debounce time of 10 seconds (10000ms)
    publish '{"debounce": 10000}' to tinkerforge/request/accelerometer_bricklet/XYZ/set_debounce_period

    # Handle incoming acceleration reached callbacks
    subscribe to tinkerforge/callback/accelerometer_bricklet/XYZ/acceleration_reached
    publish '{"register": true}' to tinkerforge/register/accelerometer_bricklet/XYZ/acceleration_reached # Register acceleration_reached callback

    # Configure threshold for acceleration "greater than 2 g, 2 g, 2 g"
    publish '{"option": "greater", "min_x": 2000, "max_x": 0, "min_y": 2000, "max_y": 0, "min_z": 2000, "max_z": 0}' to tinkerforge/request/accelerometer_bricklet/XYZ/set_acceleration_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/accelerometer_bricklet/<UID>/get_acceleration¶

Request:	empty payload
Response:	x – Type: int, Unit: 1/1000 gₙ, Range: ? y – Type: int, Unit: 1/1000 gₙ, Range: ? z – Type: int, Unit: 1/1000 gₙ, Range: ?

Returns the acceleration in x, y and z direction. The values are given in gₙ/1000 (1gₙ = 9.80665m/s²). The range is configured with request/accelerometer_bricklet/<UID>/set_configuration.

If you want to get the acceleration periodically, it is recommended to use the register/accelerometer_bricklet/<UID>/acceleration callback and set the period with request/accelerometer_bricklet/<UID>/set_acceleration_callback_period.

request/accelerometer_bricklet/<UID>/get_temperature¶

Request:	empty payload
Response:	temperature – Type: int, Unit: 1 °C, Range: [-103 to 152]

Returns the temperature of the accelerometer.

request/accelerometer_bricklet/<UID>/led_on¶

Request:	empty payload
Response:	no response

Enables the LED on the Bricklet.

request/accelerometer_bricklet/<UID>/led_off¶

Request:	empty payload
Response:	no response

Disables the LED on the Bricklet.

request/accelerometer_bricklet/<UID>/is_led_on¶

Request:	empty payload
Response:	on – Type: bool, Default: false

Returns true if the LED is enabled, false otherwise.

Advanced Functions¶

request/accelerometer_bricklet/<UID>/set_configuration¶

Request:	data_rate – Type: int, Range: See symbols, Default: 6 full_scale – Type: int, Range: See symbols, Default: 1 filter_bandwidth – Type: int, Range: See symbols, Default: 2
Response:	no response

Configures the data rate, full scale range and filter bandwidth. Possible values are:

Data rate of 0Hz to 1600Hz.
Full scale range of ±2gₙ up to ±16gₙ.
Filter bandwidth between 50Hz and 800Hz.

Decreasing data rate or full scale range will also decrease the noise on the data.

The following symbols are available for this function:

For data_rate:

"off" = 0
"3hz" = 1
"6hz" = 2
"12hz" = 3
"25hz" = 4
"50hz" = 5
"100hz" = 6
"400hz" = 7
"800hz" = 8
"1600hz" = 9

For full_scale:

"2g" = 0
"4g" = 1
"6g" = 2
"8g" = 3
"16g" = 4

For filter_bandwidth:

"800hz" = 0
"400hz" = 1
"200hz" = 2
"50hz" = 3

request/accelerometer_bricklet/<UID>/get_configuration¶

Request:	empty payload
Response:	data_rate – Type: int, Range: See symbols, Default: 6 full_scale – Type: int, Range: See symbols, Default: 1 filter_bandwidth – Type: int, Range: See symbols, Default: 2

Returns the configuration as set by request/accelerometer_bricklet/<UID>/set_configuration.

The following symbols are available for this function:

For data_rate:

"off" = 0
"3hz" = 1
"6hz" = 2
"12hz" = 3
"25hz" = 4
"50hz" = 5
"100hz" = 6
"400hz" = 7
"800hz" = 8
"1600hz" = 9

For full_scale:

"2g" = 0
"4g" = 1
"6g" = 2
"8g" = 3
"16g" = 4

For filter_bandwidth:

"800hz" = 0
"400hz" = 1
"200hz" = 2
"50hz" = 3

request/accelerometer_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 Accelerometer's name in a human readable form.

Callback Configuration Functions¶

request/accelerometer_bricklet/<UID>/set_acceleration_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/accelerometer_bricklet/<UID>/acceleration callback is triggered periodically. A value of 0 turns the callback off.

The register/accelerometer_bricklet/<UID>/acceleration callback is only triggered if the acceleration has changed since the last triggering.

request/accelerometer_bricklet/<UID>/get_acceleration_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/accelerometer_bricklet/<UID>/set_acceleration_callback_period.

request/accelerometer_bricklet/<UID>/set_acceleration_callback_threshold¶

Request:

Request:	option – Type: char, Range: See symbols, Default: "x" min_x – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0 max_x – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0 min_y – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0 max_y – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0 min_z – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0 max_z – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0
Response:	no response

option – Type: char, Range: See symbols, Default: "x"
min_x – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0
max_x – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0
min_y – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0
max_y – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0
min_z – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0
max_z – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0

Response:

no response

Sets the thresholds for the register/accelerometer_bricklet/<UID>/acceleration_reached callback.

The following options are possible:

Option	Description
'x'	Callback is turned off
'o'	Callback is triggered when the acceleration is outside the min and max values
'i'	Callback is triggered when the acceleration is inside the min and max values
'<'	Callback is triggered when the acceleration is smaller than the min value (max is ignored)
'>'	Callback is triggered when the acceleration 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/accelerometer_bricklet/<UID>/get_acceleration_callback_threshold¶

Request:

empty payload

Response:

option – Type: char, Range: See symbols, Default: "x"
min_x – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0
max_x – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0
min_y – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0
max_y – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0
min_z – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0
max_z – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0

Returns the threshold as set by request/accelerometer_bricklet/<UID>/set_acceleration_callback_threshold.

The following symbols are available for this function:

For option:

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

request/accelerometer_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/accelerometer_bricklet/<UID>/acceleration_reached

is triggered, if the threshold

request/accelerometer_bricklet/<UID>/set_acceleration_callback_threshold

keeps being reached.

request/accelerometer_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/accelerometer_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/accelerometer_bricklet/<UID>/acceleration¶

Register Request:	register – Type: bool
Callback Response:	x – Type: int, Unit: 1/1000 gₙ, Range: ? y – Type: int, Unit: 1/1000 gₙ, Range: ? z – Type: int, Unit: 1/1000 gₙ, Range: ?

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

This callback is triggered periodically with the period that is set by request/accelerometer_bricklet/<UID>/set_acceleration_callback_period. The callback payload members are the X, Y and Z acceleration. The range is configured with request/accelerometer_bricklet/<UID>/set_configuration.

The register/accelerometer_bricklet/<UID>/acceleration callback is only triggered if the acceleration has changed since the last triggering.

register/accelerometer_bricklet/<UID>/acceleration_reached¶

Register Request:	register – Type: bool
Callback Response:	x – Type: int, Unit: 1/1000 gₙ, Range: ? y – Type: int, Unit: 1/1000 gₙ, Range: ? z – Type: int, Unit: 1/1000 gₙ, Range: ?

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

This callback is triggered when the threshold as set by request/accelerometer_bricklet/<UID>/set_acceleration_callback_threshold is reached. The callback payload members are the X, Y and Z acceleration. The range is configured with request/accelerometer_bricklet/<UID>/set_configuration.

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