Demo/scripts/morse.py

   1 #! /usr/bin/env python
   2
   3 # DAH should be three DOTs.
   4 # Space between DOTs and DAHs should be one DOT.
   5 # Space between two letters should be one DAH.
   6 # Space between two words should be DOT DAH DAH.
   7
   8 import sys, math, audiodev
   9
  10 DOT = 30
  11 DAH = 3 * DOT
  12 OCTAVE = 2                              # 1 == 441 Hz, 2 == 882 Hz, ...
  13
  14 morsetab = {
  15         'A': '.-',              'a': '.-',
  16         'B': '-...',            'b': '-...',
  17         'C': '-.-.',            'c': '-.-.',
  18         'D': '-..',             'd': '-..',
  19         'E': '.',               'e': '.',
  20         'F': '..-.',            'f': '..-.',
  21         'G': '--.',             'g': '--.',
  22         'H': '....',            'h': '....',
  23         'I': '..',              'i': '..',
  24         'J': '.---',            'j': '.---',
  25         'K': '-.-',             'k': '-.-',
  26         'L': '.-..',            'l': '.-..',
  27         'M': '--',              'm': '--',
  28         'N': '-.',              'n': '-.',
  29         'O': '---',             'o': '---',
  30         'P': '.--.',            'p': '.--.',
  31         'Q': '--.-',            'q': '--.-',
  32         'R': '.-.',             'r': '.-.',
  33         'S': '...',             's': '...',
  34         'T': '-',               't': '-',
  35         'U': '..-',             'u': '..-',
  36         'V': '...-',            'v': '...-',
  37         'W': '.--',             'w': '.--',
  38         'X': '-..-',            'x': '-..-',
  39         'Y': '-.--',            'y': '-.--',
  40         'Z': '--..',            'z': '--..',
  41         '0': '-----',           ',': '--..--',
  42         '1': '.----',           '.': '.-.-.-',
  43         '2': '..---',           '?': '..--..',
  44         '3': '...--',           ';': '-.-.-.',
  45         '4': '....-',           ':': '---...',
  46         '5': '.....',           "'": '.----.',
  47         '6': '-....',           '-': '-....-',
  48         '7': '--...',           '/': '-..-.',
  49         '8': '---..',           '(': '-.--.-',
  50         '9': '----.',           ')': '-.--.-',
  51         ' ': ' ',               '_': '..--.-',
  52 }
  53
  54 nowave = '\0' * 200
  55
  56 # If we play at 44.1 kHz (which we do), then if we produce one sine
  57 # wave in 100 samples, we get a tone of 441 Hz.  If we produce two
  58 # sine waves in these 100 samples, we get a tone of 882 Hz.  882 Hz
  59 # appears to be a nice one for playing morse code.
  60 def mkwave(octave):
  61     sinewave = ''
  62     for i in range(100):
  63         val = int(math.sin(math.pi * i * octave / 50.0) * 30000)
  64         sinewave += chr((val >> 8) & 255) + chr(val & 255)
  65     return sinewave
  66
  67 defaultwave = mkwave(OCTAVE)
  68
  69 def main():
  70     import getopt
  71     try:
  72         opts, args = getopt.getopt(sys.argv[1:], 'o:p:')
  73     except getopt.error:
  74         sys.stderr.write('Usage ' + sys.argv[0] +
  75                          ' [ -o outfile ] [ -p octave ] [ words ] ...\n')
  76         sys.exit(1)
  77     dev = None
  78     wave = defaultwave
  79     for o, a in opts:
  80         if o == '-o':
  81             import aifc
  82             dev = aifc.open(a, 'w')
  83             dev.setframerate(44100)
  84             dev.setsampwidth(2)
  85             dev.setnchannels(1)
  86         if o == '-p':
  87             wave = mkwave(int(a))
  88     if not dev:
  89         import audiodev
  90         dev = audiodev.AudioDev()
  91         dev.setoutrate(44100)
  92         dev.setsampwidth(2)
  93         dev.setnchannels(1)
  94         dev.close = dev.stop
  95         dev.writeframesraw = dev.writeframes
  96     if args:
  97         source = [' '.join(args)]
  98     else:
  99         source = iter(sys.stdin.readline, '')
 100     for line in source:
 101         mline = morse(line)
 102         play(mline, dev, wave)
 103         if hasattr(dev, 'wait'):
 104             dev.wait()
 105     dev.close()
 106
 107 # Convert a string to morse code with \001 between the characters in
 108 # the string.
 109 def morse(line):
 110     res = ''
 111     for c in line:
 112         try:
 113             res += morsetab[c] + '\001'
 114         except KeyError:
 115             pass
 116     return res
 117
 118 # Play a line of morse code.
 119 def play(line, dev, wave):
 120     for c in line:
 121         if c == '.':
 122             sine(dev, DOT, wave)
 123         elif c == '-':
 124             sine(dev, DAH, wave)
 125         else:                   # space
 126             pause(dev, DAH + DOT)
 127         pause(dev, DOT)
 128
 129 def sine(dev, length, wave):
 130     for i in range(length):
 131         dev.writeframesraw(wave)
 132
 133 def pause(dev, length):
 134     for i in range(length):
 135         dev.writeframesraw(nowave)
 136
 137 if __name__ == '__main__':
 138     main()