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) three times to make the
display show “03”, then press the B button on the selector to start.
Every few seconds the speaker (SP2) randomly plays one of three siren
sounds, the U29 LED display shows a random pattern, and the
red/yellow LED (D10) will be either red, yellow, or off.
You can slow this circuit down by selecting game “01” or “02” on the
display instead of game “03”.
This circuit works the same as the preceding one, but adds more lights.
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Project 175
Random Bi-Color Lights
Project 174
Random Bi-Color Light
The red/yellow LED (D10) is a bi-color
LED, which means it has two LEDs
(red & yellow) inside, connected in
opposite directions.
Notice that when D10 is changing
colors quickly, its red and yellow colors
tend to blend into orange.
The red & green LEDs (D1 &
D2) are connected in opposite
directions between the same
points in the circuit, simulating a
second bi-color LED.