Python - Motion Detector Bricklet 2.0

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

Examples

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

Indicator

Download (example_indicator.py)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your Motion Detector Bricklet 2.0

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_motion_detector_v2 import BrickletMotionDetectorV2

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    md = BrickletMotionDetectorV2(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Turn blue backlight LEDs on (maximum brightness)
    md.set_indicator(255, 255, 255)

    raw_input("Press key to exit\n") # Use input() in Python 3
    ipcon.disconnect()

Callback

Download (example_callback.py)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your Motion Detector Bricklet 2.0

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_motion_detector_v2 import BrickletMotionDetectorV2

# Callback function for motion detected callback
def cb_motion_detected():
    print("Motion Detected")

# Callback function for detection cycle ended callback
def cb_detection_cycle_ended():
    print("Detection Cycle Ended (next detection possible in ~2 seconds)")

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    md = BrickletMotionDetectorV2(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Register motion detected callback to function cb_motion_detected
    md.register_callback(md.CALLBACK_MOTION_DETECTED, cb_motion_detected)

    # Register detection cycle ended callback to function cb_detection_cycle_ended
    md.register_callback(md.CALLBACK_DETECTION_CYCLE_ENDED, cb_detection_cycle_ended)

    raw_input("Press key to exit\n") # Use input() in Python 3
    ipcon.disconnect()

API

Generally, every function of the Python bindings can throw an tinkerforge.ip_connection.Error exception that has a value and a description property. value can have different values:

  • Error.TIMEOUT = -1
  • Error.NOT_ADDED = -6 (unused since Python bindings version 2.0.0)
  • Error.ALREADY_CONNECTED = -7
  • Error.NOT_CONNECTED = -8
  • Error.INVALID_PARAMETER = -9
  • Error.NOT_SUPPORTED = -10
  • Error.UNKNOWN_ERROR_CODE = -11
  • Error.STREAM_OUT_OF_SYNC = -12
  • Error.INVALID_UID = -13
  • Error.NON_ASCII_CHAR_IN_SECRET = -14

All functions listed below are thread-safe.

Basic Functions

BrickletMotionDetectorV2(uid, ipcon)
Parameters:
  • uid – Type: str
  • ipcon – Type: IPConnection
Returns:
  • motion_detector_v2 – Type: BrickletMotionDetectorV2

Creates an object with the unique device ID uid:

motion_detector_v2 = BrickletMotionDetectorV2("YOUR_DEVICE_UID", ipcon)

This object can then be used after the IP Connection is connected (see examples above).

BrickletMotionDetectorV2.get_motion_detected()
Returns:
  • motion – Type: int, Range: See constants

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 constants are available for this function:

For motion:

  • BrickletMotionDetectorV2.MOTION_NOT_DETECTED = 0
  • BrickletMotionDetectorV2.MOTION_DETECTED = 1
BrickletMotionDetectorV2.set_sensitivity(sensitivity)
Parameters:
  • sensitivity – Type: int, Range: [0 to 100], Default: 50
Returns:
  • None

Sets the sensitivity of the PIR sensor. 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.

BrickletMotionDetectorV2.get_sensitivity()
Returns:
  • sensitivity – Type: int, Range: [0 to 100], Default: 50

Returns the sensitivity as set by set_sensitivity().

BrickletMotionDetectorV2.set_indicator(top_left, top_right, bottom)
Parameters:
  • top_left – Type: int, Range: [0 to 255], Default: 0
  • top_right – Type: int, Range: [0 to 255], Default: 0
  • bottom – Type: int, Range: [0 to 255], Default: 0
Returns:
  • None

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.

BrickletMotionDetectorV2.get_indicator()
Return Object:
  • top_left – Type: int, Range: [0 to 255], Default: 0
  • top_right – Type: int, Range: [0 to 255], Default: 0
  • bottom – Type: int, Range: [0 to 255], Default: 0

Returns the indicator configuration as set by set_indicator().

Advanced Functions

BrickletMotionDetectorV2.get_spitfp_error_count()
Return Object:
  • 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.

BrickletMotionDetectorV2.set_bootloader_mode(mode)
Parameters:
  • mode – Type: int, Range: See constants
Returns:
  • status – Type: int, Range: See constants

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 constants are available for this function:

For mode:

  • BrickletMotionDetectorV2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletMotionDetectorV2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletMotionDetectorV2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletMotionDetectorV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletMotionDetectorV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4

For status:

  • BrickletMotionDetectorV2.BOOTLOADER_STATUS_OK = 0
  • BrickletMotionDetectorV2.BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletMotionDetectorV2.BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletMotionDetectorV2.BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletMotionDetectorV2.BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletMotionDetectorV2.BOOTLOADER_STATUS_CRC_MISMATCH = 5
BrickletMotionDetectorV2.get_bootloader_mode()
Returns:
  • mode – Type: int, Range: See constants

Returns the current bootloader mode, see set_bootloader_mode().

The following constants are available for this function:

For mode:

  • BrickletMotionDetectorV2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletMotionDetectorV2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletMotionDetectorV2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletMotionDetectorV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletMotionDetectorV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
BrickletMotionDetectorV2.set_write_firmware_pointer(pointer)
Parameters:
  • pointer – Type: int, Unit: 1 B, Range: [0 to 232 - 1]
Returns:
  • None

Sets the firmware pointer for 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.

BrickletMotionDetectorV2.write_firmware(data)
Parameters:
  • data – Type: [int, ...], Length: 64, Range: [0 to 255]
Returns:
  • status – Type: int, Range: [0 to 255]

Writes 64 Bytes of firmware at the position as written by 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.

BrickletMotionDetectorV2.set_status_led_config(config)
Parameters:
  • config – Type: int, Range: See constants, Default: 3
Returns:
  • None

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 constants are available for this function:

For config:

  • BrickletMotionDetectorV2.STATUS_LED_CONFIG_OFF = 0
  • BrickletMotionDetectorV2.STATUS_LED_CONFIG_ON = 1
  • BrickletMotionDetectorV2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletMotionDetectorV2.STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletMotionDetectorV2.get_status_led_config()
Returns:
  • config – Type: int, Range: See constants, Default: 3

Returns the configuration as set by set_status_led_config()

The following constants are available for this function:

For config:

  • BrickletMotionDetectorV2.STATUS_LED_CONFIG_OFF = 0
  • BrickletMotionDetectorV2.STATUS_LED_CONFIG_ON = 1
  • BrickletMotionDetectorV2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletMotionDetectorV2.STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletMotionDetectorV2.get_chip_temperature()
Returns:
  • temperature – Type: int, Unit: 1 °C, Range: [-215 to 215 - 1]

Returns the temperature 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.

BrickletMotionDetectorV2.reset()
Returns:
  • None

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!

BrickletMotionDetectorV2.write_uid(uid)
Parameters:
  • uid – Type: int, Range: [0 to 232 - 1]
Returns:
  • None

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.

BrickletMotionDetectorV2.read_uid()
Returns:
  • uid – Type: int, Range: [0 to 232 - 1]

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

BrickletMotionDetectorV2.get_identity()
Return Object:
  • uid – Type: str, Length: up to 8
  • connected_uid – Type: str, Length: up to 8
  • position – Type: chr, Range: ["a" to "h", "i", "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]

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). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as position 'z'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

BrickletMotionDetectorV2.register_callback(callback_id, function)
Parameters:
  • callback_id – Type: int
  • function – Type: callable
Returns:
  • None

Registers the given function with the given callback_id.

The available callback IDs with corresponding function signatures are listed below.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the register_callback() function of the device object. The first parameter is the callback ID and the second parameter the callback function:

def my_callback(param):
    print(param)

motion_detector_v2.register_callback(BrickletMotionDetectorV2.CALLBACK_EXAMPLE, my_callback)

The available constants with inherent number and type of parameters 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.

BrickletMotionDetectorV2.CALLBACK_MOTION_DETECTED
Callback Parameters:
  • no parameters

This callback is called after a motion was detected.

BrickletMotionDetectorV2.CALLBACK_DETECTION_CYCLE_ENDED
Callback Parameters:
  • no parameters

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.

Virtual Functions

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

BrickletMotionDetectorV2.get_api_version()
Return Object:
  • api_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]

Returns the version of the API definition implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

BrickletMotionDetectorV2.get_response_expected(function_id)
Parameters:
  • function_id – Type: int, Range: See constants
Returns:
  • response_expected – Type: bool

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by set_response_expected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For function_id:

  • BrickletMotionDetectorV2.FUNCTION_SET_SENSITIVITY = 2
  • BrickletMotionDetectorV2.FUNCTION_SET_INDICATOR = 4
  • BrickletMotionDetectorV2.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletMotionDetectorV2.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletMotionDetectorV2.FUNCTION_RESET = 243
  • BrickletMotionDetectorV2.FUNCTION_WRITE_UID = 248
BrickletMotionDetectorV2.set_response_expected(function_id, response_expected)
Parameters:
  • function_id – Type: int, Range: See constants
  • response_expected – Type: bool
Returns:
  • None

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For function_id:

  • BrickletMotionDetectorV2.FUNCTION_SET_SENSITIVITY = 2
  • BrickletMotionDetectorV2.FUNCTION_SET_INDICATOR = 4
  • BrickletMotionDetectorV2.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletMotionDetectorV2.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletMotionDetectorV2.FUNCTION_RESET = 243
  • BrickletMotionDetectorV2.FUNCTION_WRITE_UID = 248
BrickletMotionDetectorV2.set_response_expected_all(response_expected)
Parameters:
  • response_expected – Type: bool
Returns:
  • None

Changes the response expected flag for all setter and callback configuration functions of this device at once.

Constants

BrickletMotionDetectorV2.DEVICE_IDENTIFIER

This constant is used to identify a Motion Detector Bricklet 2.0.

The get_identity() function and the IPConnection.CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

BrickletMotionDetectorV2.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Motion Detector Bricklet 2.0.