Elenco LIGHT - Manual (Page 36)

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Project 41 Infrared Detector
Project 42 Audio Infrared Detector
You need an infrared remote control for this
project, such as any TV/stereo/DVD remote
control in your home.
Build the circuit, set the lever on the adjustable
resistor (RV) all the way towards the infrared
module (U24), and turn on the switch (S1).
Point your remote control toward the infrared
module and press any button to activate an
alarm sound. The lever on the adjustable
resistor sets how long the alarm plays for, but
it only works over a narrow range.
Next, replace the 100
Ω
resistor (R1) with the
5.1k Ω resistor (R3). The alarm sound is a little
different, but the control range on RV is wider.
Sometimes this circuit may activate without
a remote control, due to infrared in sunlight
or some room lights. If this happens, try
moving to a dark room.
Remote
You need an infrared remote
control for this project, such
as any TV/stereo/DVD
remote control in your home.
Build the circuit and turn on
the switch (S1). Point your
remote control toward the
infrared module (U24) and
press any button to activate
the red LED (D1).
Sometimes this circuit may
activate without a remote
control, due to infrared in
sunlight or some room lights.
If this happens, try moving to
a dark room.
TV remote controls transmit a
sequence of pulses representing the
TV model and the button that was
pressed. The U24 infrared detector
is just looking any infrared signal.
Remote
Sunlight and other light
sources emit some
infrared light, and may
activate the infrared
detector. See if you can
activate it without a
remote control.