class MatrixKeypad:
"""Class used to read the key interruptions from a matrix keypad"""
def __init__(self, rows, columns, digits = [], keyRepeatInterval = 300):
"""Initializes the keypad
Keyword arguments:
rows -- a list containing the rows input GPIO pin
columns -- a list containing the columns output GPIO pin
digits -- a bi-dimensional list with the keypad symbols
keyRepeatInterval -- key repeat interval in milliseconds
"""
self.rows = rows
self.columns = columns
self.digits = digits
self.keyTimer = Timer(keyRepeatInterval)
self.keyTimer.finished = True
self.readLastKey = True
for r in self.rows:
GPIO.setup(r, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
for c in self.columns:
GPIO.setup(c, GPIO.OUT)
self.lastKey = (None, None)
def onUpdate(self):
self.keyTimer.onUpdate()
for j, c in enumerate(self.columns):
GPIO.output(c, True)
for i, r in enumerate(self.rows):
if GPIO.input(r):
if self.keyTimer.isFinished() or self.lastKey != (i, j):
self.keyTimer.start()
self.lastKey = (i, j)
row, col = self.lastKey
self.readLastKey = False
GPIO.output(c, False)
def getLastKey(self):
"""Get the last key position
Return:
A tuple with (row, column) value
"""
self.readLastKey = True
return self.lastKey
def getLastDigit(self):
"""Get the last digit typed
Return:
A digit from the list of digits if this list is populated.
Otherwise returns None
"""
r, c = self.getLastKey()
if len(self.digits) > 0 and not (r == None or c == None):
return self.digits[r][c]
else:
return None
