Elenco Green Projects - Manual (Page 60)

Morse Light
Project #93 Morse Code
Project #94
Build the circuit as shown, with the
yellow LED (D5) on the pivot. Point
the yellow LED towards your friends
and push the switch (S2) several
times to send messages to your
friends using Morse Code.
You could use this system to send
messages during a noisy concert, or
out in the wilderness where your cell
phone won’t work.
During World War II Navy ships
sometimes communicated by
flashing Morse Code
messages between ships using
searchlights (because radio
transmissions might reveal their
presence to the enemy). Years
ago, Native Americans would
send messages to other tribes
using smoke signals and a
special code.
Build the circuit and push the switch (S2) several times to send secret
messages to your friends using Morse Code.
If the horn (W1) was located 10 miles away and connected to the switch
and battery (B4) using really long wires, then you could still use it to
send messages.
Morse Code: The forerunner of today’s telephone system
was the telegraph, which was widely used in the latter half of
the 19th century. It only had two states - on or off (that is,
transmitting or not transmitting), and could not send the
range of frequencies contained in human voices or music.
A code was developed to send information over long
distances using this system and a sequence of dots and
dashes (short or long transmit bursts). It was named Morse
Code after its inventor. It was also used extensively in the
early days of radio communications, though it isn’t in wide
use today. It is sometimes referred to in Hollywood movies,
especially Westerns. MORSE CODE
A . _
B _ . . .
C _ . _ .
D _ . .
E .
F . . _ .
G _ _ .
H . . . .
I . .
J . _ _ _
K _ . _
L . _ . .
M _ _
N _ .
O _ _ _
P . _ _ .
Q _ _ . _
R . _ .
S . . .
T _
U . . _
V . . . _
W . _ _
X _ . . _
Y _ . _ _
Z _ _ . .
Period . _ . _ . _
Comma _ _ . . _ _
Question . . _ _ . .
1
. _ _ _ _
2 . . _ _ _
3 . . . _ _
4 . . . . _
5 . . . . .
6 _ . . . .
7 _ _ . . .
8 _ _ _ . .
9 _ _ _ _ .
0 _ _ _ _ _
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See projects 1 & 3 if you need
to recharge the battery (B4).