MQTT - Motion Detector Bricklet 2.0

This is the description of the MQTT API bindings for the Motion Detector Bricklet 2.0. General information and technical specifications for the Motion Detector Bricklet 2.0 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).

Indicator

Download (example-indicator.txt)

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# Change XYZ to the UID of your Motion Detector Bricklet 2.0

setup:
    # Turn blue backlight LEDs on (maximum brightness)
    publish '{"top_left": 255, "top_right": 255, "bottom": 255}' to tinkerforge/request/motion_detector_v2_bricklet/XYZ/set_indicator 

Callback

Download (example-callback.txt)

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# Change XYZ to the UID of your Motion Detector Bricklet 2.0

setup:
    # Handle incoming motion detected callbacks
    subscribe to tinkerforge/callback/motion_detector_v2_bricklet/XYZ/motion_detected
    publish '{"register": true}' to tinkerforge/register/motion_detector_v2_bricklet/XYZ/motion_detected # Register motion_detected callback
    
    # Handle incoming detection cycle ended callbacks
    subscribe to tinkerforge/callback/motion_detector_v2_bricklet/XYZ/detection_cycle_ended
    publish '{"register": true}' to tinkerforge/register/motion_detector_v2_bricklet/XYZ/detection_cycle_ended # Register detection_cycle_ended callback

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/motion_detector_v2_bricklet/<UID>/get_motion_detected
Request:
  • empty payload
Response:
  • motion – Type: int, Range: See symbols

Returns 1 if a motion was detected. It returns 1 approx. for 1.8 seconds until the sensor checks for a new movement.

There is also a blue LED on the Bricklet that is on as long as the Bricklet is in the "motion detected" state.

The following symbols are available for this function:

For motion:

  • "NotDetected" = 0
  • "Detected" = 1
request/motion_detector_v2_bricklet/<UID>/set_sensitivity
Request:
  • sensitivity – Type: int, Range: [0 to 255]
Response:
  • no response

Sets the sensitivity of the PIR sensor. The range is 0-100. At full sensitivity (100), the Bricklet can detect motion in a range of approximately 12m.

The actual range depends on many things in the environment (e.g. reflections) and the size of the object to be detected. While a big person might be detected in a range of 10m a cat may only be detected at 2m distance with the same setting.

So you will have to find a good sensitivity for your application by trial and error.

The default value is 50.

request/motion_detector_v2_bricklet/<UID>/get_sensitivity
Request:
  • empty payload
Response:
  • sensitivity – Type: int, Range: [0 to 255]

Returns the sensitivity as set by request/motion_detector_v2_bricklet/<UID>/set_sensitivity.

request/motion_detector_v2_bricklet/<UID>/set_indicator
Request:
  • top_left – Type: int, Range: [0 to 255]
  • top_right – Type: int, Range: [0 to 255]
  • bottom – Type: int, Range: [0 to 255]
Response:
  • no response

Sets the blue backlight of the fresnel lens. The backlight consists of three LEDs. The brightness of each LED can be controlled with a 8-bit value (0-255). A value of 0 turns the LED off and a value of 255 turns the LED to full brightness.

The default value is 0, 0, 0.

request/motion_detector_v2_bricklet/<UID>/get_indicator
Request:
  • empty payload
Response:
  • top_left – Type: int, Range: [0 to 255]
  • top_right – Type: int, Range: [0 to 255]
  • bottom – Type: int, Range: [0 to 255]

Returns the indicator configuration as set by request/motion_detector_v2_bricklet/<UID>/set_indicator.

Advanced Functions

request/motion_detector_v2_bricklet/<UID>/get_spitfp_error_count
Request:
  • empty payload
Response:
  • error_count_ack_checksum – Type: int, Range: [0 to 232 - 1]
  • error_count_message_checksum – Type: int, Range: [0 to 232 - 1]
  • error_count_frame – Type: int, Range: [0 to 232 - 1]
  • error_count_overflow – Type: int, Range: [0 to 232 - 1]

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

request/motion_detector_v2_bricklet/<UID>/set_bootloader_mode
Request:
  • mode – Type: int, Range: See symbols
Response:
  • status – Type: int, Range: See symbols

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following symbols are available for this function:

For mode:

  • "Bootloader" = 0
  • "Firmware" = 1
  • "BootloaderWaitForReboot" = 2
  • "FirmwareWaitForReboot" = 3
  • "FirmwareWaitForEraseAndReboot" = 4

For status:

  • "OK" = 0
  • "InvalidMode" = 1
  • "NoChange" = 2
  • "EntryFunctionNotPresent" = 3
  • "DeviceIdentifierIncorrect" = 4
  • "CRCMismatch" = 5
request/motion_detector_v2_bricklet/<UID>/get_bootloader_mode
Request:
  • empty payload
Response:
  • mode – Type: int, Range: See symbols

Returns the current bootloader mode, see request/motion_detector_v2_bricklet/<UID>/set_bootloader_mode.

The following symbols are available for this function:

For mode:

  • "Bootloader" = 0
  • "Firmware" = 1
  • "BootloaderWaitForReboot" = 2
  • "FirmwareWaitForReboot" = 3
  • "FirmwareWaitForEraseAndReboot" = 4
request/motion_detector_v2_bricklet/<UID>/set_write_firmware_pointer
Request:
  • pointer – Type: int, Range: [0 to 232 - 1]
Response:
  • no response

Sets the firmware pointer for request/motion_detector_v2_bricklet/<UID>/write_firmware. The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

request/motion_detector_v2_bricklet/<UID>/write_firmware
Request:
  • data – Type: [int, ...], Length: 64, Range: [0 to 255]
Response:
  • status – Type: int, Range: [0 to 255]

Writes 64 Bytes of firmware at the position as written by request/motion_detector_v2_bricklet/<UID>/set_write_firmware_pointer before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

request/motion_detector_v2_bricklet/<UID>/set_status_led_config
Request:
  • config – Type: int, Range: See symbols
Response:
  • no response

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following symbols are available for this function:

For config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowStatus" = 3
request/motion_detector_v2_bricklet/<UID>/get_status_led_config
Request:
  • empty payload
Response:
  • config – Type: int, Range: See symbols

Returns the configuration as set by request/motion_detector_v2_bricklet/<UID>/set_status_led_config

The following symbols are available for this function:

For config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowStatus" = 3
request/motion_detector_v2_bricklet/<UID>/get_chip_temperature
Request:
  • empty payload
Response:
  • temperature – Type: int, Range: [-215 to 215 - 1]

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

request/motion_detector_v2_bricklet/<UID>/reset
Request:
  • empty payload
Response:
  • no response

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

request/motion_detector_v2_bricklet/<UID>/write_uid
Request:
  • uid – Type: int, Range: [0 to 232 - 1]
Response:
  • no response

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

request/motion_detector_v2_bricklet/<UID>/read_uid
Request:
  • empty payload
Response:
  • uid – Type: int, Range: [0 to 232 - 1]

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

request/motion_detector_v2_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
  • hardware_version – Type: [int, ...], Length: 3, Range: [0 to 255]
  • firmware_version – Type: [int, ...], Length: 3, 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' or 'd'.

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 Motion Detector 2.0's name in a human readable form.

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/motion_detector_v2_bricklet/<UID>/motion_detected
Register Request:
  • register – Type: bool
Callback Response:
  • empty payload

A callback can be registered for this event by publishing to the .../register/motion_detector_v2_bricklet/<UID>/motion_detected[/<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/motion_detector_v2_bricklet/<UID>/motion_detected[/<SUFFIX>] topic for each registered suffix.

This callback is called after a motion was detected.

register/motion_detector_v2_bricklet/<UID>/detection_cycle_ended
Register Request:
  • register – Type: bool
Callback Response:
  • empty payload

A callback can be registered for this event by publishing to the .../register/motion_detector_v2_bricklet/<UID>/detection_cycle_ended[/<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/motion_detector_v2_bricklet/<UID>/detection_cycle_ended[/<SUFFIX>] topic for each registered suffix.

This callback is called when the detection cycle ended. When this callback is called, a new motion can be detected again after approximately 2 seconds.