14
LIGHTS & SOUND
Many systems in real life are operated by light. Sometimes this is visible light like
the light from a flashlight or the sun. Sometimes it is invisible light like infrared.
Automatic doors are a good example of a system that
may be triggered by light. When you get near, either
a light beam is broken since you are in the way, or
the light pattern is changed enough to tell the
system to switch on the motor and open the
doors.
Another good example is an intruder
alarm that senses movement or, maybe,
picks up body heat - hot things radiate
infrared rays which can be found just
beyond the red end of the rainbow!
❶
LIGHT DETECTOR
Now let's see how easy the LIGHT SWITCH is
to use. Fix the Logiblocs together as shown.
Walk around in the evening and see when the
green light is on and when the red light is on. If you
need to be quiet just take off the BLEEP and
put it in your pocket.
Try shining a flashlight at the Logiblocs
from a distance. Test your target
practice by aiming the flashlight
before you turn it on. If the
BLEEP bleeps you're on
target!
