Elenco Electronics rc snap rover Bedienungsanleitung PDF herunterladen (Seite 27)

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Project #51

OBJECTIVE: To detect if a mirror is present.

Build the circuit at left. Place it where there won’t be any room light

hitting the photoresistor (RP) (such as in a dark room or under a table),

and then turn it on. The 2.5V lamp (L1) will be bright but there should

be little or no sound.

Take a small mirror and hold it over the lamp and photoresistor. You

should hear sound now. You have a reflection detector! The more light

that gets reflected like this, the louder the sound. You can try holding

the mirror at different angles and distances and see how the sound

changes. You can also hold a white piece of paper over them, since

white surfaces reflect light.

Reflection Detector

Project #52

OBJECTIVE: To detect a mirror.

Let’s modify the reflection detector circuit so that it is not so loud and

annoying. We’ll also put a lamp (L1) on it that can be seen in a noisy

room. Build the circuit at left. Place it somewhere where there won’t

be any room light hitting the photoresistor (RP) (such as in a dark

room or under a table), and then turn it on. The 2.5V lamp will be

bright but there should be little or no sound.

Take a small mirror and hold it over the lamp and photoresistor. You

should hear sound now as the mirror onto the photoresistor reflects

light from the lamp. The more light that gets reflected like this, the

louder the sound. You can also hold a white piece of paper over the

circuit, since white surfaces reflect light.

Quieter Reflection Detector

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Elenco Electronics rc snap rover Bedienungsanleitung Seite 27