schmitt_trigger.py

def schmitt_trigger(up, high, down, low, data):
    '''up is the value that when we're in low state and we hit the up value we'll go into up (going up) state.
    high is the value that when we're in up state and we hit the high value we'll go into high state.
    down is the value that when we're in high state and we hit the down value we'll go into down (going down) state.
    low is the value that when we're in down state and we hit the low value we'll go into low state.
    data is list of data values.
    '''
    result = []
    for s, val in enumerate(data):
        if val < low:
            state = 'low'
            result.append((s, 0))
            break
        elif  val > high:
            state = 'high'
            result.append((s, 1))
            break

    for i in range(s, len(data)):
        val = data[i]
        if state == 'low':
            if val >= up:
                state = 'up'
                result.append((i, 1))
        elif state == 'up':
            if val >= down:
                state = 'up2'
        elif state == 'up2':
            if val >= high:
                state = 'high'
        elif state == 'high':
            if val < down:
                state = 'down'
                result.append((i, 0))
        elif state == 'down':
            if val < up:
                state = 'down2'
        elif state == 'down2':
            if val < low:
                state = 'low'

    return result