Limit Switch

Introduction

The Limit Switch is a small digital sensor that detects physical contact with an object.

This page uses limit_switch as the example Limit Switch name. Replace it with your own configured name as needed.

Below is a list of available methods:

• pressing – Returns whether the specified Limit Switch is being pressed.

• pressed – Registers a function to be called whenever the Limit Switch is pressed.

• released – Registers a function to be called whenever the Limit Switch is released.

Constructor – Manually initialize a Limit Switch.

• Limit – Create a Limit Switch.

pressing

pressing returns a Boolean indicating whether the Limit Switch is currently being pressed. This can be used to check if the robot bumps into other objects.

• True – The Limit Switch is being pressed.

• False – The Limit Switch is not being pressed.

Usage:
limit_switch.pressing()

Parameters	Description
	This method has no parameters.

# Display a message after limit_switch is pressed
while not limit_switch.pressing():
  pass

brain.screen.print("Limit Switch pressed!")

pressed

pressed registers a function to be called whenever the Limit Switch is pressed.

Usage:
limit_switch.pressed(callback, arg)

Parameters	Description
callback	A previously defined function that executes when the Limit Switch is pressed.
arg	Optional. A tuple containing arguments to pass to the callback function. See Functions with Parameters for more information.

def my_function():
  brain.screen.print("Pressed")

# Call my_function whenever limit_switch is pressed
limit_switch.pressed(my_function)

released

released registers a function to be called whenever the Limit Switch is released.

Usage:
limit_switch.released(callback, arg)

Parameters	Description
callback	A previously defined function that executes when the Limit Switch is released.
arg	Optional. A tuple containing arguments to pass to the callback function. See Functions with Parameters for more information.

def my_function():
  brain.screen.print("Pressed")

# Call my_function whenever limit_switch is released
limit_switch.released(my_function)

Constructor

Constructors are used to manually create Limit objects, which are necessary for configuring a Limit Switch outside of VEXcode.

Limit

Limit creates a Limit Switch.

Usage:
Limit(port)

Parameter	Description
port	The 3-Wire Port that the Limit Switch is connected to: On the V5 Brain – brain.three_wire_port.x where x is the number of the port. On a 3-Wire Expander – expander.a where expander is the name of the expander instance.

# Create a Limit Switch in Port A
light_switch = Limit(brain.three_wire_port.a)