/Demo/scripts/morse.py

  1# DAH should be three DOTs.
  2# Space between DOTs and DAHs should be one DOT.
  3# Space between two letters should be one DAH.
  4# Space between two words should be DOT DAH DAH.
  5
  6import sys, math, audiodev
  7
  8DOT = 30
  9DAH = 3 * DOT
 10OCTAVE = 2                              # 1 == 441 Hz, 2 == 882 Hz, ...
 11
 12morsetab = {
 13        'A': '.-',              'a': '.-',
 14        'B': '-...',            'b': '-...',
 15        'C': '-.-.',            'c': '-.-.',
 16        'D': '-..',             'd': '-..',
 17        'E': '.',               'e': '.',
 18        'F': '..-.',            'f': '..-.',
 19        'G': '--.',             'g': '--.',
 20        'H': '....',            'h': '....',
 21        'I': '..',              'i': '..',
 22        'J': '.---',            'j': '.---',
 23        'K': '-.-',             'k': '-.-',
 24        'L': '.-..',            'l': '.-..',
 25        'M': '--',              'm': '--',
 26        'N': '-.',              'n': '-.',
 27        'O': '---',             'o': '---',
 28        'P': '.--.',            'p': '.--.',
 29        'Q': '--.-',            'q': '--.-',
 30        'R': '.-.',             'r': '.-.',
 31        'S': '...',             's': '...',
 32        'T': '-',               't': '-',
 33        'U': '..-',             'u': '..-',
 34        'V': '...-',            'v': '...-',
 35        'W': '.--',             'w': '.--',
 36        'X': '-..-',            'x': '-..-',
 37        'Y': '-.--',            'y': '-.--',
 38        'Z': '--..',            'z': '--..',
 39        '0': '-----',
 40        '1': '.----',
 41        '2': '..---',
 42        '3': '...--',
 43        '4': '....-',
 44        '5': '.....',
 45        '6': '-....',
 46        '7': '--...',
 47        '8': '---..',
 48        '9': '----.',
 49        ',': '--..--',
 50        '.': '.-.-.-',
 51        '?': '..--..',
 52        ';': '-.-.-.',
 53        ':': '---...',
 54        "'": '.----.',
 55        '-': '-....-',
 56        '/': '-..-.',
 57        '(': '-.--.-',
 58        ')': '-.--.-',
 59        '_': '..--.-',
 60        ' ': ' '
 61}
 62
 63# If we play at 44.1 kHz (which we do), then if we produce one sine
 64# wave in 100 samples, we get a tone of 441 Hz.  If we produce two
 65# sine waves in these 100 samples, we get a tone of 882 Hz.  882 Hz
 66# appears to be a nice one for playing morse code.
 67def mkwave(octave):
 68    global sinewave, nowave
 69    sinewave = ''
 70    for i in range(100):
 71        val = int(math.sin(math.pi * float(i) * octave / 50.0) * 30000)
 72        sinewave = sinewave + chr((val >> 8) & 255) + chr(val & 255)
 73    nowave = '\0' * 200
 74
 75mkwave(OCTAVE)
 76
 77def main():
 78    import getopt, string
 79    try:
 80        opts, args = getopt.getopt(sys.argv[1:], 'o:p:')
 81    except getopt.error:
 82        sys.stderr.write('Usage ' + sys.argv[0] +
 83                         ' [ -o outfile ] [ args ] ...\n')
 84        sys.exit(1)
 85    dev = None
 86    for o, a in opts:
 87        if o == '-o':
 88            import aifc
 89            dev = aifc.open(a, 'w')
 90            dev.setframerate(44100)
 91            dev.setsampwidth(2)
 92            dev.setnchannels(1)
 93        if o == '-p':
 94            mkwave(string.atoi(a))
 95    if not dev:
 96        import audiodev
 97        dev = audiodev.AudioDev()
 98        dev.setoutrate(44100)
 99        dev.setsampwidth(2)
100        dev.setnchannels(1)
101        dev.close = dev.stop
102        dev.writeframesraw = dev.writeframes
103    if args:
104        line = string.join(args)
105    else:
106        line = sys.stdin.readline()
107    while line:
108        mline = morse(line)
109        play(mline, dev)
110        if hasattr(dev, 'wait'):
111            dev.wait()
112        if not args:
113            line = sys.stdin.readline()
114        else:
115            line = ''
116    dev.close()
117
118# Convert a string to morse code with \001 between the characters in
119# the string.
120def morse(line):
121    res = ''
122    for c in line:
123        try:
124            res = res + morsetab[c] + '\001'
125        except KeyError:
126            pass
127    return res
128
129# Play a line of morse code.
130def play(line, dev):
131    for c in line:
132        if c == '.':
133            sine(dev, DOT)
134        elif c == '-':
135            sine(dev, DAH)
136        else:                   # space
137            pause(dev, DAH + DOT)
138        pause(dev, DOT)
139
140def sine(dev, length):
141    for i in range(length):
142        dev.writeframesraw(sinewave)
143
144def pause(dev, length):
145    for i in range(length):
146        dev.writeframesraw(nowave)
147
148if __name__ == '__main__' or sys.argv[0] == __name__:
149    main()