xmas_tree/tree2.py

   1 # Example code for [charlieplexed] GPIO Xmas Tree for
   2 # Raspberry Pi by Andrew Gale.
   3
   4 import RPi.GPIO as GPIO
   5 import time
   6
   7 # The tree connects to the 6 GPIO pins furthest away from the
   8 # corner of Raspberry Pi i.e. *physical* pin numbers 21-26 on
   9 # the model A or B and 35-40 on the B+.
  10
  11 # Some Kickstarter supporters opted to receive a 'bi-colour'
  12 # LED as their stretch goal reward. This fits in the top
  13 # LED position (i.e. LED_0) but actually contains a second
  14 # LED that we shall call LED_7
  15
  16 # Bicolour LED fitted or not?
  17 # bicolour_fitted = False # the default is False
  18 bicolour_fitted = True # the default is False
  19
  20 # The time for which each LED is illuminated.
  21 # This is the place to tweak the brightness of the bicolour
  22 # LEDs by altering their illumination time.
  23 illumination_time_bicolour_green = 0.004 # the ON time for the bicolour green LED
  24 illumination_time_bicolour_red = 0.004 # the ON time for the bicolour red LED
  25 illumination_time_default = 0.001 # the ON time for all the other LEDs
  26
  27 # The following constants will be configured by tree.setup()
  28 # but we will set them to -1 for now.
  29 A, B, C, D = -1, -1, -1, -1  # The four Charlieplexing nodes
  30 total_illumination_time = -1 # Time for one whole cycle
  31
  32 RR1 = 1 # Red LEDs on right tree
  33 RR2 = 2
  34 RR3 = 3
  35 RR4 = 4
  36 RR5 = 5
  37 RR6 = 6
  38 RBA = 7 # Right bicolour amber
  39 RBG = 8 # Right bicolour green
  40 RBR = 9 # Right bicolour red
  41
  42 LR1 = 11 # Red LEDs on right tree
  43 LR2 = 12
  44 LR3 = 13
  45 LR4 = 14
  46 LR5 = 15
  47 LR6 = 16
  48 LBA = 17 # Right bicolour amber
  49 LBG = 18 # Right bicolour green
  50 LBR = 19 # Right bicolour red
  51
  52 POSSIBLE_LEDS = [RR1, RR2, RR3, RR4, RR5, RR6, RBG, RBR,
  53                  LR1, LR2, LR3, LR4, LR5, LR6, LBG, LBR]
  54
  55
  56 # The following code to detect which version of Raspberry Pi
  57 # you are using is courtesy of Matt Hawkins at
  58 # http://www.raspberrypi-spy.co.uk
  59
  60 def getrevision():
  61   # Extract board revision from cpuinfo file
  62   myrevision = "0000"
  63   try:
  64     f = open('/proc/cpuinfo','r')
  65     for line in f:
  66       if line[0:8]=='Revision':
  67         length=len(line)
  68         myrevision = line[11:length-1]
  69     f.close()
  70   except:
  71     myrevision = "0000"
  72
  73   return myrevision
  74
  75
  76
  77 def single_led_on(n):
  78   if (A==-1):
  79     print "***********************************************"
  80     print "**                                           **"
  81     print "** ERROR: you MUST call tree.setup() first!! **"
  82     print "**                                           **"
  83     print "***********************************************"
  84     raise Exception('You MUST call tree.setup() first!!')
  85
  86   # First, set all the nodes to be input (effectively
  87   # 'disconnecting' them from the Raspberry Pi)
  88   GPIO.setup(A, GPIO.IN)
  89   GPIO.setup(B, GPIO.IN)
  90   GPIO.setup(C, GPIO.IN)
  91   GPIO.setup(D, GPIO.IN)
  92   GPIO.setup(A2, GPIO.IN)
  93   GPIO.setup(B2, GPIO.IN)
  94   GPIO.setup(C2, GPIO.IN)
  95   GPIO.setup(D2, GPIO.IN)
  96
  97   # Now determine which nodes are connected to the anode
  98   # and cathode for this LED
  99   if   (n==RBG): anode, cathode = C, A
 100   elif (n==RR1): anode, cathode = C, D
 101   elif (n==RR2): anode, cathode = D, C
 102   elif (n==RR3): anode, cathode = D, B
 103   elif (n==RR4): anode, cathode = B, D
 104   elif (n==RR5): anode, cathode = A, B
 105   elif (n==RR6): anode, cathode = B, A
 106   elif (n==RBR): anode, cathode = A, C
 107   elif (n==LBG): anode, cathode = C2, A2
 108   elif (n==LR1): anode, cathode = C2, D2
 109   elif (n==LR2): anode, cathode = D2, C2
 110   elif (n==LR3): anode, cathode = D2, B2
 111   elif (n==LR4): anode, cathode = B2, D2
 112   elif (n==LR5): anode, cathode = A2, B2
 113   elif (n==LR6): anode, cathode = B2, A2
 114   elif (n==LBR): anode, cathode = A2, C2
 115   else: return # invalid LED number
 116
 117   # Configure the anode and cathode nodes to be outputs
 118   GPIO.setup(anode, GPIO.OUT)
 119   GPIO.setup(cathode, GPIO.OUT)
 120
 121   # Make the anode high (+3.3v) and the cathode low (0v)
 122   GPIO.output(anode, GPIO.HIGH)
 123   GPIO.output(cathode, GPIO.LOW)
 124
 125
 126 def leds_on_and_wait(leds, wait_time):
 127   # This routine is passed a list of LEDs to illumnate.
 128   # The whole routine
 129   # loops around as many times as it can in the time specified
 130   # in the "wait_time" parameter, thereby creating the illusion
 131   # that all LEDs are on simultaneously (due to persistence
 132   # of vision) when, in reality, only one is on at a time.
 133
 134   # When used with a bicolour LED at the top of the tree, this
 135   # routine is passed a 9-bit value.
 136   # Bit 7 is for the red LED in the bicolour LED.
 137   # Bit 8 is for the green LED in the bicolour LED.
 138   # Bit 0: to maintain compatibility with code for a non-bicolour version of
 139   # the tree, if bit 0 is set then we want the bicolour LED to light BOTH LEDs
 140   # to mimic the yellow of the non-bicolour version of the tree.
 141
 142   led_set = set(leds)
 143   if RBA in led_set:
 144     led_set.discard(RBA)
 145     led_set.add(RBG)
 146     led_set.add(RBR)
 147   if LBA in led_set:
 148     led_set.discard(LBA)
 149     led_set.add(LBG)
 150     led_set.add(LBR)
 151
 152   if led_set & set(POSSIBLE_LEDS):
 153     elapsed = 0
 154     while elapsed < wait_time:
 155       for i in led_set:
 156         single_led_on(i)
 157
 158         if (bicolour_fitted and (i == RBG or i == LBG)):
 159           this_wait = illumination_time_bicolour_green
 160         elif (bicolour_fitted and (i == RBR or i == LBR)):
 161           this_wait = illumination_time_bicolour_red
 162         else:
 163           this_wait = illumination_time_default
 164         elapsed += this_wait
 165         time.sleep(this_wait)
 166   else:
 167       all_leds_off()
 168       time.sleep(wait_time)
 169
 170
 171 def all_leds_off():
 172   single_led_on(0)
 173
 174 def setup():
 175   global A
 176   global B
 177   global C
 178   global D
 179   global A2
 180   global B2
 181   global C2
 182   global D2
 183   global total_illumination_time
 184
 185   GPIO.setmode(GPIO.BCM)
 186
 187   # choose the correct GPIO pins depending on model
 188   revision = getrevision()
 189   print "** revision: ", revision
 190   if ((revision == "0010") or (revision == "0012")):
 191     print "Model B+ or A+"
 192     A, B, C, D = 21, 19, 26, 20
 193   else:
 194     print "Other model, probably Model A or Model B"
 195     print "Pi 2"
 196     # A, B, C, D = 7, 9, 11, 8
 197     A, B, C, D = 15, 3, 4, 14 # near corner
 198     A2, B2, C2, D2 = 21, 19, 26, 20 # near USB
 199
 200
 201   if (bicolour_fitted):
 202     total_illumination_time = 6 * illumination_time_default
 203     total_illumination_time += illumination_time_bicolour_green
 204     total_illumination_time += illumination_time_bicolour_red
 205   else:
 206     total_illumination_time = 8 * illumination_time_default
 207
 208   #print "total_illumination_time: ", total_illumination_time
 209
 210 def cleanup():
 211   GPIO.cleanup()
 212