libstp.step.motion.move_until.strafe

Factory functions for strafing laterally until an IR sensor detects a surface color.

Prerequisites:

Strafing requires a mecanum or holonomic drivetrain capable of lateral movement. These steps will have no lateral effect on a differential-drive robot.

Functions

strafe_until_black(...)

Strafe laterally until any sensor detects a black surface.

strafe_until_white(...)

Strafe laterally until any sensor detects a white surface.

strafe_left_until_black(...)

Strafe left until any sensor detects a black surface.

strafe_left_until_white(...)

Strafe left until any sensor detects a white surface.

strafe_right_until_black(...)

Strafe right until any sensor detects a black surface.

strafe_right_until_white(...)

Strafe right until any sensor detects a white surface.

Module Contents

libstp.step.motion.move_until.strafe.strafe_until_black(sensor: libstp.sensor_ir.IRSensor | list[libstp.sensor_ir.IRSensor], strafe_speed: float, confidence_threshold: float = 0.7) → libstp.step.motion.move_until.core.MoveUntil

Strafe laterally until any sensor detects a black surface.

Commands a constant lateral velocity and polls the given IR sensor(s) each control cycle. The step completes as soon as any sensor’s probabilityOfBlack() meets or exceeds confidence_threshold. This is the low-level variant that accepts a signed strafe speed; prefer the directional helpers strafe_left_until_black / strafe_right_until_black for most use cases.

Prerequisites:

Requires a mecanum or holonomic drivetrain capable of lateral movement.

Parameters:

  • sensor – A single IRSensor or a list of sensors. The step triggers when any sensor in the list detects black.

  • strafe_speed – Lateral speed in m/s. Positive values strafe left, negative values strafe right.

  • confidence_threshold – Minimum probability (0.0 – 1.0) that the sensor must report for black before the step considers the condition met. Defaults to 0.7.

Returns:

A configured motion step that strafes and stops when black is detected.

Return type:

MoveUntil

Example:

from libstp.sensor_ir import IRSensor

side_ir = IRSensor(1)
# Strafe left at 0.2 m/s until black is found
step = strafe_until_black(side_ir, strafe_speed=0.2)
libstp.step.motion.move_until.strafe.strafe_until_white(sensor: libstp.sensor_ir.IRSensor | list[libstp.sensor_ir.IRSensor], strafe_speed: float, confidence_threshold: float = 0.7) → libstp.step.motion.move_until.core.MoveUntil

Strafe laterally until any sensor detects a white surface.

Commands a constant lateral velocity and polls the given IR sensor(s) each control cycle. The step completes as soon as any sensor’s probabilityOfWhite() meets or exceeds confidence_threshold. This is the low-level variant that accepts a signed strafe speed; prefer the directional helpers strafe_left_until_white / strafe_right_until_white for most use cases.

Prerequisites:

Requires a mecanum or holonomic drivetrain capable of lateral movement.

Parameters:

  • sensor – A single IRSensor or a list of sensors. The step triggers when any sensor in the list detects white.

  • strafe_speed – Lateral speed in m/s. Positive values strafe left, negative values strafe right.

  • confidence_threshold – Minimum probability (0.0 – 1.0) that the sensor must report for white before the step considers the condition met. Defaults to 0.7.

Returns:

A configured motion step that strafes and stops when white is detected.

Return type:

MoveUntil

Example:

from libstp.sensor_ir import IRSensor

side_ir = IRSensor(1)
# Strafe right at 0.2 m/s until white is found
step = strafe_until_white(side_ir, strafe_speed=-0.2)
libstp.step.motion.move_until.strafe.strafe_left_until_black(sensor: libstp.sensor_ir.IRSensor | list[libstp.sensor_ir.IRSensor], speed: float = 0.3, confidence_threshold: float = 0.7) → libstp.step.motion.move_until.core.MoveUntil

Strafe left until any sensor detects a black surface.

Commands a constant leftward lateral velocity and polls the given IR sensor(s) each control cycle. The step completes as soon as any sensor’s probabilityOfBlack() meets or exceeds confidence_threshold. The speed is negated internally to produce leftward motion, so you should pass a positive value.

Prerequisites:

Requires a mecanum or holonomic drivetrain capable of lateral movement.

Parameters:

  • sensor – A single IRSensor or a list of sensors. The step triggers when any sensor in the list detects black.

  • speed – Lateral speed in m/s. Pass a positive value; the sign is negated internally to strafe left. Defaults to 0.3.

  • confidence_threshold – Minimum probability (0.0 – 1.0) that the sensor must report for black before the step considers the condition met. Defaults to 0.7.

Returns:

A configured motion step that strafes left and stops when black is detected.

Return type:

MoveUntil

Example:

from libstp.sensor_ir import IRSensor

left_ir = IRSensor(1)

# Strafe left at 0.2 m/s until the left sensor finds a black line
step = strafe_left_until_black(left_ir, speed=0.2)
libstp.step.motion.move_until.strafe.strafe_left_until_white(sensor: libstp.sensor_ir.IRSensor | list[libstp.sensor_ir.IRSensor], speed: float = 0.3, confidence_threshold: float = 0.7) → libstp.step.motion.move_until.core.MoveUntil

Strafe left until any sensor detects a white surface.

Commands a constant leftward lateral velocity and polls the given IR sensor(s) each control cycle. The step completes as soon as any sensor’s probabilityOfWhite() meets or exceeds confidence_threshold. The speed is negated internally to produce leftward motion, so you should pass a positive value.

Prerequisites:

Requires a mecanum or holonomic drivetrain capable of lateral movement.

Parameters:

  • sensor – A single IRSensor or a list of sensors. The step triggers when any sensor in the list detects white.

  • speed – Lateral speed in m/s. Pass a positive value; the sign is negated internally to strafe left. Defaults to 0.3.

  • confidence_threshold – Minimum probability (0.0 – 1.0) that the sensor must report for white before the step considers the condition met. Defaults to 0.7.

Returns:

A configured motion step that strafes left and stops when white is detected.

Return type:

MoveUntil

Example:

from libstp.sensor_ir import IRSensor

left_ir = IRSensor(1)

# Strafe left at default speed until the left sensor finds white
step = strafe_left_until_white(left_ir)
libstp.step.motion.move_until.strafe.strafe_right_until_black(sensor: libstp.sensor_ir.IRSensor | list[libstp.sensor_ir.IRSensor], speed: float = 0.3, confidence_threshold: float = 0.7) → libstp.step.motion.move_until.core.MoveUntil

Strafe right until any sensor detects a black surface.

Commands a constant rightward lateral velocity and polls the given IR sensor(s) each control cycle. The step completes as soon as any sensor’s probabilityOfBlack() meets or exceeds confidence_threshold. The speed is forced positive (rightward) regardless of the sign passed in.

Prerequisites:

Requires a mecanum or holonomic drivetrain capable of lateral movement.

Parameters:

  • sensor – A single IRSensor or a list of sensors. The step triggers when any sensor in the list detects black.

  • speed – Lateral speed in m/s. The absolute value is used, so negative inputs are treated as positive. Defaults to 0.3.

  • confidence_threshold – Minimum probability (0.0 – 1.0) that the sensor must report for black before the step considers the condition met. Defaults to 0.7.

Returns:

A configured motion step that strafes right and stops when black is detected.

Return type:

MoveUntil

Example:

from libstp.sensor_ir import IRSensor

right_ir = IRSensor(3)

# Strafe right at 0.25 m/s until the right sensor hits a black line
step = strafe_right_until_black(right_ir, speed=0.25)
libstp.step.motion.move_until.strafe.strafe_right_until_white(sensor: libstp.sensor_ir.IRSensor | list[libstp.sensor_ir.IRSensor], speed: float = 0.3, confidence_threshold: float = 0.7) → libstp.step.motion.move_until.core.MoveUntil

Strafe right until any sensor detects a white surface.

Commands a constant rightward lateral velocity and polls the given IR sensor(s) each control cycle. The step completes as soon as any sensor’s probabilityOfWhite() meets or exceeds confidence_threshold. The speed is forced positive (rightward) regardless of the sign passed in.

Prerequisites:

Requires a mecanum or holonomic drivetrain capable of lateral movement.

Parameters:

  • sensor – A single IRSensor or a list of sensors. The step triggers when any sensor in the list detects white.

  • speed – Lateral speed in m/s. The absolute value is used, so negative inputs are treated as positive. Defaults to 0.3.

  • confidence_threshold – Minimum probability (0.0 – 1.0) that the sensor must report for white before the step considers the condition met. Defaults to 0.7.

Returns:

A configured motion step that strafes right and stops when white is detected.

Return type:

MoveUntil

Example:

from libstp.sensor_ir import IRSensor

right_ir = IRSensor(3)

# Strafe right at default speed until the right sensor finds white
step = strafe_right_until_white(right_ir)

# Use multiple sensors with high confidence
bottom_ir = IRSensor(4)
step = strafe_right_until_white(
    [right_ir, bottom_ir], speed=0.2, confidence_threshold=0.85
)