Elenco Electronics Snap Circuits Light - Photo Infrared Detector; Photo Audio Infrared Detector; Photo Audio Infrared Detector (II)

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Project 43 Photo Infrared Detector
Project 44 Photo Audio Infrared Detector
Project 45
Photo Audio
Infrared
Detector
(II)
Use the preceding circuit,
but replace the 0.1µF
capacitor (C2) with the
100µF capacitor (C4). The
circuit works the same way,
but the sound stays on
longer and is more
pleasant.
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). Place the
mounting base (normally
used with the fiber optic tree)
on the phototransistor (Q4).
Set the lever on the
adjustable resistor (RV) so
the sound just turns off (if it
never turns off, move away
from room lights. Point your
remote control directly into
the mounting base on Q4,
and press any button to
activate the sound.
Remote
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). Place the mounting base
(normally used with the fiber optic tree)
on the phototransistor (Q4). Set the
lever on the adjustable resistor (RV) so
the red LED (D1) just turns off; if it
never turns off, move away from room
lights. Point your remote control directly
into the mounting base on Q4, and
press any button to activate the red
LED (D1).
The phototransistor can
detect light, and infrared
light is light. The infrared
module (U24) is designed to
focus only on infrared light.