Project 13
European Siren & Light
Turn on the slide
switch (S1). A
European siren
sounds and the
color LED (D8)
flashes.
Modify the project 13 circuit by
moving the 2-snap wire that is on
top of the alarm IC (U2), as shown.
Project 16
Fire Engine
Siren & Light
Modify the project 13
circuit by moving the 2-
snap wire and 1-snap wire
that are on top of the
alarm IC (U2), as shown.
Project 17
Machine Gun
Sound & Light
Modify the preceding circuit by
removing the 3-snap wire that
is on top of the alarm IC (U2),
and adding three 2-snap wires
around it, as shown.
Project 15
Silly Sound &
Light
Modify the project 13 circuit by
removing the 2-snap wire and
1-snap wire that are on top of
the alarm IC (U2), as shown.
Project 14
Siren & Light
The lower-right snap of the alarm IC (U2) is like an
electrical gate, opening and closing quickly to let small
bursts of electric current flow in. The bursts of electric
current also flow through the color LED (lighting it) and
the speaker (which produces sound). The alarm IC
produces the different siren sounds by adjusting the
pattern of current bursts through the speaker.
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