Apr 2017

When I designed the PCB for this project. I did what most people would do and I made the PCB the 'right way up' with 40 Way Raspberry pi header and the 7 Segment LED also the normal way up (so you can read it). Later on I realised this was a bit of a mistake, because this means the Raspberry Pi Zero Power and USB connections are now at the bottom, so you can't power this up and put it on a table :(.

Fear not though, with some help I have edited the code so that it writes the time upside-down, so if you rotate your Raspberry Pi 180° you can read the time correctly, and still put it on the table. Below is the adjusted code.

Please NOTE: You do NOT have to rotate the 7 Segment LED on the PCB, the code does this for you.

<sxh [py][; options for SyntaxHighlighter]> #! /usr/bin/python # Python Script to run a 7 Segment Common Anode LED as a clock. # Version 1.0 import RPi.GPIO as GPIO import time

#Define numbering system for the IO pins Raspberry Pi GPIO.setmode(GPIO.BCM)

# Define GPIO ports for the 7seg gpioSegments = (5,6,13,19,26,21,20,16) # 7seg_segment_pins (11,7,4,2,1,10,5,3) + 100R inline # Setup channels for output and set initial values for segment in (gpioSegments):

GPIO.setup(segment,GPIO.OUT)
GPIO.output(segment,GPIO.HIGH)
        

# Define GPIO ports for the digits 0-3 gpioDigits = (18,23,24,25) gpioDigits = (25,24,23,18) # Pins (12,9,8,6) select digits 0-3 respectively reading LTR on display # Setup channels for output and set initial values for digit in (gpioDigits):

GPIO.setup(digit,GPIO.OUT)
GPIO.output(digit,GPIO.LOW)

#Define flags for comtrol of Colon separator on display colon_visible=True colon_counter=0

#Define segment arrays for each number to be displayed numbers = {

'0':(0,0,1,0,1,0,0,0),
  '1':(0,1,1,1,1,1,0,1), 
  '2':(0,0,1,1,0,0,1,0), 
  '3':(0,0,1,1,0,1,0,0), 
  '4':(0,1,1,0,0,1,0,1), 
  '5':(1,0,1,0,0,1,0,0), 
  '6':(1,0,1,0,0,0,0,0), 
  '7':(0,0,1,1,1,1,0,1), 
  '8':(0,0,1,0,0,0,0,0), 
  '9':(0,0,1,0,0,1,0,0), 
  ' ':(0,0,0,0,0,0,0,0)}

#Cycle through each digit and its segments try:

  while True:
      time_string = str(time.ctime()[11:13]+time.ctime()[14:16]).rjust(4)
      for digit in range(4):

#select digit to display

          GPIO.output(gpioDigits[digit], 2)

#set required segments on

          for segment in range(0,8):
              GPIO.output(gpioSegments[segment], numbers[time_string[digit]][segment]) 

#check to see if we are on segment 3 of digit 2(LTR)

              if ((digit==2) and (segment==2)):

#when colon counter gets to set value flip colon display mode between TRUE (visible) and False (NOT.visible)

				if (colon_counter<=25):

#count value not reached turn colon ON or OFF based on current setting of colon_visible

					if colon_visible==True:
						GPIO.output(13, 0)
					else:
						GPIO.output(13, 1)

#colon counter set value reached so flip colon display mode and reset colon counter

				else:
					colon_counter = 0
					colon_visible =  not colon_visible

#display all selected segments for a short time

          time.sleep(0.005)

#turn-off All segments

          for segment in range(0,8):
              GPIO.output(gpioSegments[segment],GPIO.HIGH)

#turn-off current digit selector pin

          GPIO.output(gpioDigits[digit], GPIO.LOW)

#advance colon counter

      colon_counter=colon_counter+1

finally:

GPIO.cleanup()

</sxh>