How to do it...

Create a script called tilt.py to report the state of the tilt switch:

#!/usr/bin/python3 
#tilt.py 
import RPi.GPIO as GPIO 
#HARDWARE SETUP 
# GPIO 
# 2[===========T=]26[=======]40 
# 1[=============]25[=======]39 
#Tilt Config 
TILT_SW = 24 
 
def tilt_setup(): 
  #Setup the wiring 
  GPIO.setmode(GPIO.BOARD) 
  #Setup Ports 
  GPIO.setup(TILT_SW,GPIO.IN,pull_up_down=GPIO.PUD_UP) 
 
def tilt_moving(): 
  #Report the state of the Tilt Switch 
  return GPIO.input(TILT_SW) 
 
def main(): 
  import time 
  tilt_setup() 
  while True: 
    print("TILT %s"% (GPIO.input(TILT_SW))) 
    time.sleep(0.1) 
 
if __name__=='__main__': 
  try: 
    main() 
  finally: 
    GPIO.cleanup() 
    print("Closed Everything. END") 
#End

You can test the script by running it directly with the following command:

sudo python3 tilt.py

Add the following rgbled_pov() function to the rgbled.py script we created previously; this will allow us to display a single line of our image:

def rgbled_pov(led_pattern,color,ontime): 
  '''Disable all the LEDs and re-enable the LED pattern in the required color''' 
  led_deactivate(LED,RGB) 
  for led_num,col_num in enumerate(led_pattern): 
    if col_num >= 1: 
      led_activate(LED[led_num],color) 
  time.sleep(ontime)

We will now create the following file, called rgbledmessage.py, to perform the required actions to display our message. First, we will import the modules used: the updated rgbled module, the new tilt module, and the Python os module. Initially, we set DEBUG to True, so the Python terminal will display additional information while the script is running:

#!/usr/bin/python3 
# rgbledmessage.py 
import rgbled as RGBLED 
import tilt as TILT 
import os 
 
DEBUG = True

Add a readMessageFile() function to read the content of the letters.txt file and then add processFileContent() to generate a Python dictionary of the LED patterns for each letter:

def readMessageFile(filename): 
  assert os.path.exists(filename), 'Cannot find the message file: %s' % (filename) 
  try: 
    with open(filename, 'r') as theFile: 
    fileContent = theFile.readlines() 
  except IOError: 
    print("Unable to open %s" % (filename)) 
  if DEBUG:print ("File Content START:") 
  if DEBUG:print (fileContent) 
  if DEBUG:print ("File Content END") 
  dictionary = processFileContent(fileContent) 
  return dictionary  
 
def processFileContent(content): 
  letterIndex = [] #Will contain a list of letters stored in the file 
  letterList = []  #Will contain a list of letter formats 
  letterFormat = [] #Will contain the format of each letter 
  firstLetter = True 
  nextLetter = False 
  LETTERDIC={} 
  #Process each line that was in the file 
  for line in content: 
    # Ignore the # as comments 
    if '#' in line: 
      if DEBUG:print ("Comment: %s"%line) 
    #Check for " in the line = index name   
    elif '"' in line: 
      nextLetter = True 
      line = line.replace('"','') #Remove " characters 
      LETTER=line.rstrip() 
      if DEBUG:print ("Index: %s"%line) 
    #Remaining lines are formatting codes 
    else: 
      #Skip firstLetter until complete 
      if firstLetter: 
        firstLetter = False 
        nextLetter = False 
        lastLetter = LETTER 
      #Move to next letter if needed 
      if nextLetter: 
        nextLetter = False 
        LETTERDIC[lastLetter]=letterFormat[:] 
        letterFormat[:] = [] 
        lastLetter = LETTER 
      #Save the format data 
      values = line.rstrip().split(' ') 
      row = [] 
      for val in values: 
        row.append(int(val)) 
      letterFormat.append(row) 
  LETTERDIC[lastLetter]=letterFormat[:] 
  #Show letter patterns for debugging 
  if DEBUG:print ("LETTERDIC: %s" %LETTERDIC) 
  if DEBUG:print ("C: %s"%LETTERDIC['C']) 
  if DEBUG:print ("O: %s"%LETTERDIC['O']) 
  return LETTERDIC

Add a createBuffer() function, which will convert a message into a series of LED patterns for each letter (assuming the letter is defined by the letters.txt file):

def createBuffer(message,dictionary): 
  buffer=[] 
  for letter in message: 
    try: 
      letterPattern=dictionary[letter] 
    except KeyError: 
      if DEBUG:print("Unknown letter %s: use _"%letter) 
      letterPattern=dictionary['_'] 
    buffer=addLetter(letterPattern,buffer) 
  if DEBUG:print("Buffer: %s"%buffer) 
  return buffer 
 
def addLetter(letter,buffer): 
  for row in letter: 
    buffer.append(row) 
  buffer.append([0,0,0,0,0]) 
  buffer.append([0,0,0,0,0]) 
  return buffer

Next, we define a displayBuffer() function to display the LED patterns using the rgbled_pov() function in the rgbled module:

def displayBuffer(buffer): 
  position=0 
  while(1): 
    if(TILT.tilt_moving()==False): 
      position=0 
    elif (position+1)<len(buffer): 
      position+=1 
      if DEBUG:print("Pos:%s ROW:%s"%(position,buffer[position])) 
    RGBLED.rgbled_pov(buffer[position],RGBLED.RGB_GREEN,0.001) 
    RGBLED.rgbled_pov(buffer[position],RGBLED.RGB_BLUE,0.001)

Finally, we create a main() function to perform each of the required steps:
1. Set up the hardware components (RGB LEDs and the tilt switch).
2. Read the letters.txt file.
3. Define the dictionary of LED letter patterns.
4. Generate a buffer to represent the required message.
5. Display the buffer using the rgbled module and control it with the tilt module:

def main(): 
  RGBLED.led_setup() 
  TILT.tilt_setup() 
  dict=readMessageFile('letters.txt') 
  buffer=createBuffer('_COOKBOOK_',dict) 
  displayBuffer(buffer) 
   
if __name__=='__main__': 
  try: 
    main() 
  finally: 
    RGBLED.led_cleanup() 
    print("Closed Everything. END") 
#End

Create the following file, called letters.txt, to define the LED patterns needed to display the example '_COOKBOOK_' message. Note that this file only needs to define a pattern for each unique letter or symbol in the message:

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