Elenco Motion Detector - Manual (Page 2)

Turn on the switch (S1) to see light and
hear a buzzing sound. The buzzing is
synchonized with the changing light.
Project 7 Low Light & Sound
Project 6 Light & Sound
Turn on the switch (S1) to
see light and hear sound. If
desired, place the egg on
the color LED D8).
+
Turn on the switch (S1) to see light and hear the horn (W1). The
horn is synchonized with the changing light from the color LED (D8).
As a variant, try swapping the locations of the color LED & horn.
The tilt switch (S7) is used as a spacer here, and is not electrically
connected.
Project 8
Super Light & Sound
Project 5
Horn
Use the circuit from project 4, but
replace the color LED (D8) with
the horn (W1, “+” on left). Turn on
the switch (S1) to hear the horn.
Build the circuit as shown,
and turn on the slide
switch (S1). The color
LED (D8) is changing
colors in a repeating
pattern. If desired, place
the egg on the color LED.
For best effects, place the
circuit in a dimly lit room.
Project 4 Color Light
+
Egg
(place on
color LED)
Placement Level Numbers
The NPN transistor (Q2) can be used as an electronic switch, allowing
one circuit to control another.
When the color LED changes colors, the electric current through it also
changes. The NPN transistor uses this changing current to control the
electric current through the horn, which changes the sound it produces.
When you swap the locations of the color LED & horn, the electric
current through the horn is now controlling the electric current through
the color LED. The horn current is not changing like the LED current
was, so now both the horn and color LED just operate normally.
This circuit has the color LED and horn
connected in a series (not in parallel, as in
project 5). This arrangement makes the
LED dimmer and the sound less loud, but
makes the batteries last longer.
The color LED is a light emitting diode,
which converts electrical energy into
light; the color of the light emitted
depends on the characteristics of the
material used. The color LED actually
contains separate red, green, and blue
light emitting diodes, with a micro-
circuit controlling them. LEDs are more
energy efficient than normal light bulbs.
The horn converts electricity into
sound by making mechanical
vibrations. These vibrations create
variations in air pressure which
travel across the room. You “hear”
when your ears feel these air
pressure variations.
SCP-13_022014.qxp_SCP-13 Instructions 3/7/14 10:46 AM Page 2