104 lines
3.1 KiB
Python
104 lines
3.1 KiB
Python
# #####################################################
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# Python Library for 3x4 matrix keypad using
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# 7 of the avialable GPIO pins on the Raspberry Pi.
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#
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# This could easily be expanded to handle a 4x4 but I
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# don't have one for testing. The KEYPAD constant
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# would need to be updated. Also the setting/checking
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# of the colVal part would need to be expanded to
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# handle the extra column.
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#
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# Written by Chris Crumpacker
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# May 2013
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#
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# main structure is adapted from Bandono's
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# matrixQPI which is wiringPi based.
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# https://github.com/bandono/matrixQPi?source=cc
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# #####################################################
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import RPi.GPIO as GPIO
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class keypad():
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# CONSTANTS
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KEYPAD = [
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[1,2,3],
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[4,5,6],
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[7,8,9],
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["*",0,"#"]
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]
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ROW = [18,23,24,25]
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COLUMN = [5,6,13]
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# COLUMN = [4,17,22]
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def __init__(self):
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GPIO.setmode(GPIO.BCM)
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def getKey(self):
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# Set all columns as output low
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for j in range(len(self.COLUMN)):
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GPIO.setup(self.COLUMN[j], GPIO.OUT)
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GPIO.output(self.COLUMN[j], GPIO.LOW)
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# Set all rows as input
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for i in range(len(self.ROW)):
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GPIO.setup(self.ROW[i], GPIO.IN, pull_up_down=GPIO.PUD_UP)
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# Scan rows for pushed key/button
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# A valid key press should set "rowVal" between 0 and 3.
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rowVal = -1
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for i in range(len(self.ROW)):
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tmpRead = GPIO.input(self.ROW[i])
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if tmpRead == 0:
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rowVal = i
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# if rowVal is not 0 thru 3 then no button was pressed and we can exit
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if rowVal <0 or rowVal >3:
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self.exit()
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return
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# Convert columns to input
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for j in range(len(self.COLUMN)):
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GPIO.setup(self.COLUMN[j], GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
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# Switch the i-th row found from scan to output
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GPIO.setup(self.ROW[rowVal], GPIO.OUT)
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GPIO.output(self.ROW[rowVal], GPIO.HIGH)
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# Scan columns for still-pushed key/button
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# A valid key press should set "colVal" between 0 and 2.
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colVal = -1
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for j in range(len(self.COLUMN)):
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tmpRead = GPIO.input(self.COLUMN[j])
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if tmpRead == 1:
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colVal=j
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# if colVal is not 0 thru 2 then no button was pressed and we can exit
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if colVal <0 or colVal >2:
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self.exit()
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return
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# Return the value of the key pressed
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self.exit()
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return self.KEYPAD[rowVal][colVal]
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def exit(self):
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# Reinitialize all rows and columns as input at exit
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for i in range(len(self.ROW)):
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GPIO.setup(self.ROW[i], GPIO.IN, pull_up_down=GPIO.PUD_UP)
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for j in range(len(self.COLUMN)):
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GPIO.setup(self.COLUMN[j], GPIO.IN, pull_up_down=GPIO.PUD_UP)
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if __name__ == '__main__':
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# Initialize the keypad class
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kp = keypad()
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# Loop while waiting for a keypress
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digit = None
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while digit == None:
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digit = kp.getKey()
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# Print the result
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print digit
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