Elenco Circuit Maker Sound Plus 200 - Manual (Page 59)

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Project #142
Mail Notifying Electronic Lamp
Turn on the slide switch (S1). If
there is enough light on the
photoresistor (RP), the lamp (L4)
will not light. Place your finger over
the photoresistor and now the lamp
lights. The lamp will stay on until
you turn off the slide switch. A
simple mail notifying system can
be made using this circuit.
If the photoresistor and the red
LED (D1) were inside the mailbox
facing each other, then if there
were mail, the light would be
blocked from the photoresistor and
the lamp would turn on.
Project #145
Lasting Doorbell
Place the 10mF capacitor (C3) on top of the whistle chip (WC).
Press and release the press switch (S2). It makes a clicking
sound that repeats for a while.
Build the circuit on the left;
note that there is a 4-snap
wire on layer 1 that is not
connected to a 3-snap wire
that runs over it on layer 3.
Turn on the slide switch (S1),
then press and release the
press switch (S2). There is a
doorbell sound that slowly
fades away.
When the press switch is
pressed, the transistors (Q1,
Q2) are supplied with current
for oscillation. At the same
time, the 100mF capacitor
(C4) is being charged. When
the press switch is released,
the capacitor discharges and
keeps the oscillation going
for a while.
Project #146 Lasting Clicking
Use the Project #145 circuit but replace the 100mF capacitor (C4)
with the 10mF capacitor (C3). Press and release the press switch
(S2). It makes a tone that lasts a few seconds.
Project #147 Shorter Doorbell
Use the preceding circuit but replace the 1KW resistor (R2) with
the 5.1KW resistor (R3) and lamp (L4) with the red LED (D1), with
“+” on left. Press and release the press switch (S2). It makes a
tone and lights the LED for a few seconds.
Project #148 Lighted Doorbell
You can replace the 0.1mF capacitor (C2) with the whistle chip
(WC) to add sound.
Project #143
Mail Notifying Electronic
Lamp & Sound
Using a 1-snap, place the speaker (SP2) at across locations E2-
G6. When the lamp turns off the speaker will sound briefly.
Project #144
Mail Notifying Mode Change
CM-200_Manual_031914.qxp_CM-200_Manual_031914 4/2/14 12:04 PM Page 59