10 01 clock.py

10_01_clock.py

@@ -0,0 +1,24 @@
+#!/usr/bin/python
+# 10_01_clock.py
+
+import i2c7segment as display
+import time
+
+disp = display.Adafruit7Segment()
+
+while True:
+	h = time.localtime().tm_hour
+	m = time.localtime().tm_min
+
+	#Original code
+	#	disp.print_int(h * 100 + m)
+
+	#Modified code
+	disp.write_time_digits(h,m)
+
+	disp.draw_colon(True)
+	disp.write_display()
+	time.sleep(0.5)
+	disp.draw_colon(False)
+	disp.write_display()
+	time.sleep(0.5)

10_01_clock_explained.py

@@ -0,0 +1,31 @@
+#!/usr/bin/python
+# 10_01_clock.py
+
+import i2c7segment as display
+import time
+"""
+The 'print_int()' as found in the 'i2c7segment' module does not display leading zeros which are required for a clock display. 
+As well, it does not clear all digits prior to updating with the integer value, potentially leaving the display is an unintends state.
+
+The 'write_time_digits(arg1, arg2)' was added to the 'i2c7segment' module to better address the display of time components.
+arg1 and arg2 can be any two-digit time component, eg. year, month, day, hours, minutes, seconds
+"""
+
+disp = display.Adafruit7Segment()
+
+while True:
+	h = time.localtime().tm_hour
+	m = time.localtime().tm_min
+
+	#Original code
+	#	disp.print_int(h * 100 + m)
+
+	#Modified code
+	disp.write_time_digits(h,m)
+
+	disp.draw_colon(True)
+	disp.write_display()
+	time.sleep(0.5)
+	disp.draw_colon(False)
+	disp.write_display()
+	time.sleep(0.5)

README.md

@@ -1,4 +1,6 @@
 monk_raspberrypi
 ================
 
-Raspberry Pi code by Simon Monk for the book Programming Raspberry Pi: Getting Started with Python
+Raspberry Pi code by Simon Monk for the book Programming Raspberry Pi: Getting Started with Python
+
+My observations and proposed changes to the original files '10_01_clock.py' and 'i2c7segment.py'

i2c7segment.py

@@ -0,0 +1,132 @@
+import smbus
+import sys
+"""
+This is a library for using the Adafruit i2c 4 digit 7 segment LED displays
+with i2c on a Raspberry Pi. It was built and tested on Raspbian Wheezy.
+
+This is not an Adafruit product. 
+
+To get i2c to work, you need Raspbian Wheezy or later and to do:
+ sudo apt-get install python-smbus
+ sudo apt-get install i2c-tools (usefull but not essential)
+ sudo modprobe i2c-dev
+ sudo modprobe i2c-bcm2708
+
+Example Usage:
+
+disp = Adafruit7Segment()
+raw_input("print_int(65535, 16)")
+disp.print_int(65535, 16)
+disp.write_display()
+raw_input("print_int(1234)")
+disp.print_int(1234)
+disp.write_display()
+raw_input("print_str(----)")
+disp.print_str('----')
+disp.write_display()
+raw_input("print_str(-12.3)")
+disp.print_str('-12.3')
+disp.write_display()
+
+Simon Monk http://www.simonmonk.org Please give credit where credit is due.
+
+"""
+
+"""
+This module originally written by Simon Monk, has been modified by 
+Mark Hache, BSc(Comp Sci) UNB1992, 
+contact:  [email protected]
+"""
+
+number_table = [0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x07, 0x7F, 0x6F, 0x77, 0x7C, 0x39, 0x5E, 0x79, 0x71]
+
+class Adafruit7Segment:
+
+    def __init__(self, address=0x70):
+        self.address = address
+        #Original code
+	#	self.bus = smbus.SMBus(0)
+	#Modified code
+	try:
+        	self.bus = smbus.SMBus(0)
+        except IOError:
+		try:
+			self.bus = smbus.SMBus(1)
+		except IOError:
+			print('Error occurred while setting up i2c bus.')
+			print('Neither i2c0 nor i2c1 is available.')
+			sys.exit()
+        #End of modified code
+	self.disp = [0, 0, 0, 0, 0] #digit1 digit2 digit3 digit4 colon
+        self.bus.write_byte(address, 0x21)
+        self.set_brightness(15)
+        self.set_blink_rate(1)
+
+    def set_brightness(self, brightness):
+        """Set brightness 0 to 15"""
+        self.bus.write_byte(self.address, 0xE0 | brightness)
+
+    def set_blink_rate(self, blink):
+        """Blink Rate 0, 1 or 2"""
+        self.bus.write_byte(self.address, 0x80 | blink)
+
+    def write_digit_raw(self, digit, bitmask):
+        """ Write the LED segments for a digit directly dp g f e d c b a """
+        self.disp[digit] = bitmask
+
+    def write_digit_num(self, digit, number, dot=False):
+        """ Write a number into a digit position optionally with a dot"""
+        bitmask = number_table[number]
+        if dot:
+            bitmask = bitmask | 0x80
+        self.write_digit_raw(digit, bitmask)
+
+    def draw_colon(self, show_colon):
+        """ Turn the colon in the middle on or off"""
+        if show_colon:
+            self.disp[4] = 0xFF
+        else:
+            self.disp[4] = 0x00
+
+    def write_display(self):
+        """ Refresh the display - nothing will appear until you call this"""
+        self.bus.write_i2c_block_data(self.address, 0x00, [self.disp[0], 0x00, self.disp[1], 0x00, self.disp[4], 0x00, self.disp[2], 0x00, self.disp[3], 0x00])
+
+    def print_int(self, n, base=10):
+        """ Pint the integer, optionally with number base (2..16)"""
+        i = 0
+        while n > 0:
+            self.write_digit_num(3-i, n % base, False)
+            n = n / base
+            i = i + 1
+
+    def print_str(self, s):
+        """
+        Do the best you can with a 4 digit string (more with dots)
+        this is how you deal with floats and signs etc
+        format it first then print it
+        unknown characters print as a space
+        """
+        digit_index = 0
+        string_index = 0
+        while string_index < len(s):
+            ch = s[string_index]
+            if ch == '-':
+                self.write_digit_raw(digit_index, 0x40)
+            elif ch >= '0' and ch <= '9':
+                followed_by_dp = False
+                if string_index < len(s)-1 and s[string_index+1] == '.':
+                    followed_by_dp = True
+                    string_index = string_index + 1
+                self.write_digit_num(digit_index, int(ch), followed_by_dp)
+            else:
+                string_index = string_index + 1
+            string_index = string_index + 1
+            digit_index = digit_index + 1
+
+#Newly added 'write_time_digits(arg1, arg2)'
+    def write_time_digits(self,h_m,m_s):
+	self.write_digit_raw(0,number_table[h_m//10])
+	self.write_digit_raw(1,number_table[h_m%10])
+	self.write_digit_raw(2,number_table[m_s//10])
+	self.write_digit_raw(3,number_table[m_s%10])

i2c7segment_explained.py

@@ -0,0 +1,151 @@
+import smbus
+import sys
+"""
+This is a library for using the Adafruit i2c 4 digit 7 segment LED displays
+with i2c on a Raspberry Pi. It was built and tested on Raspbian Wheezy.
+
+This is not an Adafruit product. 
+
+To get i2c to work, you need Raspbian Wheezy or later and to do:
+ sudo apt-get install python-smbus
+ sudo apt-get install i2c-tools (usefull but not essential)
+ sudo modprobe i2c-dev
+ sudo modprobe i2c-bcm2708
+
+Example Usage:
+
+disp = Adafruit7Segment()
+raw_input("print_int(65535, 16)")
+disp.print_int(65535, 16)
+disp.write_display()
+raw_input("print_int(1234)")
+disp.print_int(1234)
+disp.write_display()
+raw_input("print_str(----)")
+disp.print_str('----')
+disp.write_display()
+raw_input("print_str(-12.3)")
+disp.print_str('-12.3')
+disp.write_display()
+
+Simon Monk http://www.simonmonk.org Please give credit where credit is due.
+
+"""
+
+"""
+This module originally written by Simon Monk, has been modified by 
+Mark Hache, BSc(Comp Sci) UNB1992, 
+contact:  [email protected]
+
+Issue 1.0 29 Sep 2014
+The original module was written with the Rasberry Pi models A and B.  
+
+In those models, the i2c bus connected to the GPIO pins is 'i2c0'.  Originally, this module 
+hard-coded the use of this bus.  
+However, with the release of the Rasberry Pi B+, the i2c bus connected to the GPIO pins is 'i2c1'.  
+The module has been modified to work with any model of the Rasberry Pi, A, B or B+.
+
+Issue 2.0 30 Sep 2014
+'print_int()' asimplemented is not suitable for displaying time values as it suppresses leading 
+zeroes and it fails to clear all digits prior to updating the display potentially leaving the 
+display in an unintended state.
+
+'write_time_digits(self, arg1, arg2)' is added to the 'i2c7segment.py' module to better address 
+the display of time components. arg1 and arg2 can be any two-digit time component, eg. year, month,
+day, hours, minutes, seconds 
+"""
+
+number_table = [0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x07, 0x7F, 0x6F, 0x77, 0x7C, 0x39, 0x5E, 0x79, 0x71]
+
+class Adafruit7Segment:
+
+    def __init__(self, address=0x70):
+        self.address = address
+	#Issue 1.
+        #Original code
+	#	self.bus = smbus.SMBus(0)
+	#Modified code
+	try:
+        	self.bus = smbus.SMBus(0)
+        except IOError:
+		try:
+			self.bus = smbus.SMBus(1)
+		except IOError:
+			print('Error occurred while setting up i2c bus.')
+			print('Neither i2c0 nor i2c1 is available.')
+			sys.exit()
+        #End of modified code
+	self.disp = [0, 0, 0, 0, 0] #digit1 digit2 digit3 digit4 colon
+        self.bus.write_byte(address, 0x21)
+        self.set_brightness(15)
+        self.set_blink_rate(1)
+
+    def set_brightness(self, brightness):
+        """Set brightness 0 to 15"""
+        self.bus.write_byte(self.address, 0xE0 | brightness)
+
+    def set_blink_rate(self, blink):
+        """Blink Rate 0, 1 or 2"""
+        self.bus.write_byte(self.address, 0x80 | blink)
+
+    def write_digit_raw(self, digit, bitmask):
+        """ Write the LED segments for a digit directly dp g f e d c b a """
+        self.disp[digit] = bitmask
+
+    def write_digit_num(self, digit, number, dot=False):
+        """ Write a number into a digit position optionally with a dot"""
+        bitmask = number_table[number]
+        if dot:
+            bitmask = bitmask | 0x80
+        self.write_digit_raw(digit, bitmask)
+
+    def draw_colon(self, show_colon):
+        """ Turn the colon in the middle on or off"""
+        if show_colon:
+            self.disp[4] = 0xFF
+        else:
+            self.disp[4] = 0x00
+
+    def write_display(self):
+        """ Refresh the display - nothing will appear until you call this"""
+        self.bus.write_i2c_block_data(self.address, 0x00, [self.disp[0], 0x00, self.disp[1], 0x00, self.disp[4], 0x00, self.disp[2], 0x00, self.disp[3], 0x00])
+
+    def print_int(self, n, base=10):
+        """ Pint the integer, optionally with number base (2..16)"""
+        i = 0
+        while n > 0:
+            self.write_digit_num(3-i, n % base, False)
+            n = n / base
+            i = i + 1
+
+    def print_str(self, s):
+        """
+        Do the best you can with a 4 digit string (more with dots)
+        this is how you deal with floats and signs etc
+        format it first then print it
+        unknown characters print as a space
+        """
+        digit_index = 0
+        string_index = 0
+        while string_index < len(s):
+            ch = s[string_index]
+            if ch == '-':
+                self.write_digit_raw(digit_index, 0x40)
+            elif ch >= '0' and ch <= '9':
+                followed_by_dp = False
+                if string_index < len(s)-1 and s[string_index+1] == '.':
+                    followed_by_dp = True
+                    string_index = string_index + 1
+                self.write_digit_num(digit_index, int(ch), followed_by_dp)
+            else:
+                string_index = string_index + 1
+            string_index = string_index + 1
+            digit_index = digit_index + 1
+
+#Issue2
+#Newly added 'write_time_digits(arg1, arg2)'
+    def write_time_digits(self,h_m,m_s):
+	self.write_digit_raw(0,number_table[h_m//10])
+	self.write_digit_raw(1,number_table[h_m%10])
+	self.write_digit_raw(2,number_table[m_s//10])
+	self.write_digit_raw(3,number_table[m_s%10])