Schmitt Trigger
The schmitt_trigger.py module provides a set of classes for implementing Schmitt Triggers. A Schmitt Trigger is a comparator circuit with hysteresis. It is used to detect signals in a noisy environment by providing separate thresholds for a rising and a falling edge.
SchmittState Enum
An enum representing the state of the Schmitt Trigger.
HIGH: The state is high.LOW: The state is low.
AbstractSchmittTrigger
An abstract base class for Schmitt Triggers.
add(x)
Adds a new value to the trigger and returns the new state if it changed.
SchmittTrigger
A basic Schmitt Trigger implementation.
__init__(self, high_bound, low_bound, invert=False):high_bound: The upper threshold.low_bound: The lower threshold.invert: Inverts the trigger’s behavior.
Usage Example
from flexlib.models.schmitt_trigger import SchmittTrigger
trigger = SchmittTrigger(high_bound=10, low_bound=5)
print(trigger.state) # Output: SchmittState.LOW
print(trigger.add(8)) # Output: None
print(trigger.add(12)) # Output: SchmittState.HIGH
print(trigger.state) # Output: SchmittState.HIGH
print(trigger.add(6)) # Output: None
print(trigger.add(4)) # Output: SchmittState.LOW
print(trigger.state) # Output: SchmittState.LOWCountingSchmittTrigger
A Schmitt Trigger that only changes state after a certain number of consecutive values have crossed the threshold.
__init__(self, high_bound, low_bound, invert=False, low_count=0, high_count=0):low_count: The number of consecutive values required to transition to the LOW state.high_count: The number of consecutive values required to transition to the HIGH state.
Usage Example
from flexlib.models.schmitt_trigger import CountingSchmittTrigger
trigger = CountingSchmittTrigger(high_bound=10, low_bound=5, high_count=3)
print(trigger.add(11)) # Output: None
print(trigger.add(12)) # Output: None
print(trigger.add(13)) # Output: SchmittState.HIGHDelayedSchmittTrigger
A Schmitt Trigger that only changes state after a certain duration has passed since the first value crossed the threshold. This is useful for time-based events.
__init__(self, high_bound, low_bound, low_duration=datetime.timedelta(0), high_duration=datetime.timedelta(0), invert=False):low_duration: The duration required to transition to the LOW state.high_duration: The duration required to transition to the HIGH state.
Usage Example
import datetime
from flexlib.models.schmitt_trigger import DelayedSchmittTrigger, TimedComparable
trigger = DelayedSchmittTrigger(high_bound=10, low_bound=5, high_duration=datetime.timedelta(seconds=2))
now = datetime.datetime.now()
print(trigger.add(TimedComparable(11, now))) # Output: None
print(trigger.add(TimedComparable(12, now + datetime.timedelta(seconds=1)))) # Output: None
print(trigger.add(TimedComparable(13, now + datetime.timedelta(seconds=3)))) # Output: SchmittState.HIGHPredicate-based Triggers
The module also provides predicate-based Schmitt Triggers (PredicateSchmittTrigger, CountingPredicateSchmittTrigger, DelayedPredicateSchmittTrigger) that use functions to determine if a threshold is crossed, allowing for more complex conditions.