User Manual

Turn on the slide switch (S1); the display on the LED-MC (U29) shows
“00”. Press the A button on the selector (S8) once to make the display
show “01”, then press the B button on the selector to start.
Every few seconds the speaker (SP2) randomly plays one of three siren
sounds, and the U29 LED display shows a random pattern.
Modify the project 128 circuit by
adding the red & red/yellow LEDs
(D1 & D10) as shown. It works the
same way, but has more lights and
the sound is not as loud.
Use the preceding circuit. Turn on the slide switch (S1); the display on
the LED-MC (U29) shows “00”. Press the A button on the selector (S8)
two or three times to increase the ones digit on the display. When the
display shows “02” or “03”, press the B button on the selector to start.
The circuit works the same, except that it changes faster. “03” is faster
than “02”.
Project 129
Fast Random Siren
Selector
Modify the preceding
circuit by adding the
LEDs in the disco motor
(DM) using blue & red
jumper wires as shown. It
works the same way, but
has more lights.
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Project 128
Random Siren Selector
Project 130
LED Random Siren
Selector
Project 131
5-LED Random Siren
Selector