1. Add a delay between each character (just so that it’s easy to disntinguish
    one character from the next when you look at the LED). This delay should
    be shorter than the “inter-word” delay at the end of loop().

  2. Surround all the statements within loop() with a for loop that
    produces 5 “SOS” messages, and then executes a long-ish “inter-message”
    delay (say, 5 seconds).

  3. Modify the first for loop so that it produces 3 short blinks, modify the
    second for loop so that it produces 3 medium-length blinks, and modify the third
    for loop so that it produces 3 long blinks. (This doesn’t have any particular
    meaning in Morse code, it’s just an exercise in using for loops.)

  4. Replace the for loops in the sample sketch with a set of 4 for loops
    which produce the light pattern for the digits 0 through 3:

(For a much easier way to implement digits in Morse code, see the packet
on writing functions).

  1. Use the LED to spell out “help” instead of “SOS”. Some of the letters
    in “help” are well suited to using for loops, and others are not.
  1. Try implementing any of the “TODO’s” above as while loops instead.

  2. Set up a global variable delayTime and initialize it with a value of 1000.
    Then, in loop(), implement a while loop that:

delayTime = delayTime * 0.9;

After the while loop, reset delayTime back to 1000 msec.