rpi_gpio.py

#!/usr/bin/python

import RPi.GPIO as GPIO
import time
from threading import Timer

DEFAULT_KEY_DELAY = 300
DEFAULT_REPEAT_DELAY = 1.0
DEFAULT_REPEAT_RATE = 1.0
DEFAULT_DEBOUNCE_TIME = 10

class KeypadFactory():

    def create_keypad(self, keypad=None, row_pins=None, col_pins=None, key_delay=DEFAULT_KEY_DELAY, repeat=False, repeat_delay=None, repeat_rate=None, gpio_mode=GPIO.BCM):

        if keypad is None:
            keypad = [
                [1,2,3],
                [4,5,6],
                [7,8,9],
                ["*",0,"#"]
            ]

        if row_pins is None:
            row_pins = [4,14,15,17]

        if col_pins is None:
            col_pins = [18,27,22]

        return Keypad(keypad, row_pins, col_pins, key_delay, repeat, repeat_delay, repeat_rate, gpio_mode)

    def create_4_by_3_keypad(self):

        KEYPAD = [
            [1,2,3],
            [4,5,6],
            [7,8,9],
            ["*",0,"#"]
        ]

        ROW_PINS = [4,14,15,17]
        COL_PINS = [18,27,22]

        return self.create_keypad(KEYPAD, ROW_PINS, COL_PINS)

    def create_4_by_4_keypad(self):

        KEYPAD = [
            [1,2,3,"A"],
            [4,5,6,"B"],
            [7,8,9,"C"],
            ["*",0,"#","D"]
        ]

        ROW_PINS = [4,14,15,17]
        COL_PINS = [18,27,22,23]

        return self.create_keypad(KEYPAD, ROW_PINS, COL_PINS)

class Keypad():
    def __init__(self, keypad, row_pins, col_pins, key_delay=DEFAULT_KEY_DELAY, repeat=False, repeat_delay=None, repeat_rate=None,gpio_mode=GPIO.BCM):
        self._handlers = []

        self._keypad = keypad
        self._row_pins = row_pins
        self._col_pins = col_pins
        self._key_delay = key_delay
        self._repeat = repeat
        self._repeat_delay = repeat_delay
        self._repeat_rate = repeat_rate
        self._repeat_timer = None
        if repeat:
            self._repeat_delay = repeat_delay if repeat_delay is not None else DEFAULT_REPEAT_DELAY
            self._repeat_rate = repeat_rate if repeat_rate is not None else DEFAULT_REPEAT_RATE
        else:
            if repeat_delay is not None:
                self._repeat = True
                self._repeat_rate = repeat_rate if repeat_rate is not None else DEFAULT_REPEAT_RATE
            elif repeat_rate is not None:
                self._repeat = True
                self._repeat_delay = repeat_delay if repeat_delay is not None else DEFAULT_REPEAT_DELAY

        self._last_key_press_time = 0
        self._first_repeat = True

        GPIO.setmode(gpio_mode)

        self._setRowsAsInput()
        self._setColumnsAsOutput()

    def registerKeyPressHandler(self, handler):
        self._handlers.append(handler)

    def unregisterKeyPressHandler(self, handler):
        self._handlers.remove(handler)

    def clearKeyPressHandlers(self):
        self._handlers = []

    def _repeatTimer(self):
        self._repeat_timer = None
        self._onKeyPress(None)

    def _onKeyPress(self, channel):
        currTime = self.getTimeInMillis()
        if currTime < self._last_key_press_time + self._key_delay:
            return

        keyPressed = self.getKey()
        if keyPressed is not None:
            for handler in self._handlers:
                handler(keyPressed)
            self._last_key_press_time = currTime
            if self._repeat:
                self._repeat_timer = Timer(self._repeat_delay if self._first_repeat else 1.0/self._repeat_rate, self._repeatTimer)
                self._first_repeat = False
                self._repeat_timer.start()
        else:
            if self._repeat_timer is not None:
                self._repeat_timer.cancel()
            self._repeat_timer = None
            self._first_repeat = True

    def _setRowsAsInput(self):
        # Set all rows as input
        for i in range(len(self._row_pins)):
            GPIO.setup(self._row_pins[i], GPIO.IN, pull_up_down=GPIO.PUD_UP)
            GPIO.add_event_detect(self._row_pins[i], GPIO.FALLING, callback=self._onKeyPress, bouncetime=DEFAULT_DEBOUNCE_TIME)

    def _setColumnsAsOutput(self):
        # Set all columns as output low
        for j in range(len(self._col_pins)):
            GPIO.setup(self._col_pins[j], GPIO.OUT)
            GPIO.output(self._col_pins[j], GPIO.LOW)

    def getKey(self):

        keyVal = None

        # Scan rows for pressed key
        rowVal = None
        for i in range(len(self._row_pins)):
            tmpRead = GPIO.input(self._row_pins[i])
            if tmpRead == 0:
                rowVal = i
                break

        # Scan columns for pressed key
        colVal = None
        if rowVal is not None:
            for i in range(len(self._col_pins)):
                GPIO.output(self._col_pins[i], GPIO.HIGH)
                if GPIO.input(self._row_pins[rowVal]) == GPIO.HIGH:
                    GPIO.output(self._col_pins[i], GPIO.LOW)
                    colVal = i
                    break
                GPIO.output(self._col_pins[i], GPIO.LOW)

        # Determine pressed key, if any
        if colVal is not None:
            keyVal = self._keypad[rowVal][colVal]

        return keyVal

    def cleanup(self):
        if self._repeat_timer is not None:
            self._repeat_timer.cancel()
        GPIO.cleanup()

    def getTimeInMillis(self):
        return time.time() * 1000

if __name__ == "__main__":
    from pad4pi import rpi_gpio

    KEYPAD = [
        ["F1", "F2", "#", "*"],
        [1, 2, 3, "Up"],
        [4, 5, 6, "Down"],
        [7, 8, 9, "Esc"],
        ["Left", 0, "Right", "Ent"]
        ]
    ROW_PINS = [4, 17, 18, 27, 22]
    COL_PINS = [9, 10, 24, 23]
    kp = rpi_gpio.KeypadFactory().create_keypad(keypad=KEYPAD, row_pins=ROW_PINS, col_pins=COL_PINS, repeat=True, repeat_rate=5, key_delay=100)
    def printkey(key):
        print(key)
    kp.registerKeyPressHandler(printkey)
    i = raw_input('')
    kp.cleanup()