ForceSensor

The LEGO® Education SPIKE™ Prime Force Sensor (also known as the LEGO® Technic Force Sensor) can measure pressure of up to 10 newtons (N), but it can also be used as a touch sensor or a simple button.

class buildhat.ForceSensor(port, threshold_force=1)

Force sensor

Parameters:: port – Port of device
Raises:: DeviceError – Occurs if there is no force sensor attached to port

callback(func)

Set callback function

Parameters:: func – Callback function

property connected

Whether device is connected or not

Returns:: Connection status

static desc_for_id(typeid)

Translate integer type id to something more descriptive than the device name

Parameters:: typeid – Type of device
Returns:: Description of device

property description

Device on port info

Returns:: Device description

deselect(): Unselect data from mode

get()

Extract information from device

Returns:: Data from device
Raises:: DeviceError – Occurs if device not in valid mode

get_force()

Return the force in (N)

Returns:: The force exerted on the button
Return type:: int

get_peak_force()

Get the maximum force registered since the sensor was reset

(The sensor gets reset when the firmware is reloaded)

Returns:: 0 - 100
Return type:: int

property interval

Interval between data points in milliseconds

Getter:: Gets interval
Setter:: Sets interval
Returns:: Device interval
Return type:: int

is_pressed()

Get whether the button is pressed

Returns:: If button is pressed
Return type:: bool

isconnected()

Whether it is connected or not

Raises:: DeviceError – Occurs if device no longer the same

mode(modev)

Set combimode or simple mode

Parameters:: modev – List of tuples for a combimode, or integer for simple mode

property name

Determine name of device on port

Returns:: Device name

static name_for_id(typeid)

Translate integer type id to device name (python class)

Parameters:: typeid – Type of device
Returns:: Name of device

off(): Turn off sensor

on(): Turn on sensor

reverse(): Reverse polarity

select()

Request data from mode

Raises:: DeviceError – Occurs if device not in valid mode

property threshold_force

Threshold force

Getter:: Returns threshold force
Setter:: Sets threshold force
Returns:: Threshold force

property typeid

Type ID of device

Returns:: Type ID

property typeidcur

Type ID currently present

Returns:: Type ID

wait_until_pressed(force=1)

Wait until the button is pressed

Parameters:: force – Optional

wait_until_released(force=0)

Wait until the button is released

Parameters:: force – Optional

property when_pressed

Handle force events

Getter:: Returns function to be called when pressed
Setter:: Sets function to be called when pressed
Returns:: Callback function

property when_released

Handle force events

Getter:: Returns function to be called when released
Setter:: Sets function to be called when released
Returns:: Callback function

Example

"""Example using force sensor"""

from signal import pause

from buildhat import ForceSensor, Motor

motor = Motor('A')
button = ForceSensor('D', threshold_force=1)

print("Waiting for button to be pressed fully and released")

button.wait_until_pressed(100)
button.wait_until_released(0)

motor.run_for_rotations(1)

print("Wait for button to be pressed")

button.wait_until_pressed()
motor.run_for_rotations(2)


def handle_pressed(force):
    """Force sensor pressed

    :param force: Force value
    """
    print("pressed", force)


def handle_released(force):
    """Force sensor released

    :param force: Force value
    """
    print("released", force)


button.when_pressed = handle_pressed
button.when_released = handle_released
pause()