Project #682, Relay-whistle vibrator, Project #683 – Elenco Projects 512-692 User Manual
Page 81: Relay-whistle photo vibrator

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Project #682
OBJECTIVE: To show how electricity can lift things using magnetism.
Relay-Whistle Vibrator
Take a paperclip and straighten it out, bend it in half, and
place it into the electromagnet (M3) center. Connect the
electromagnet to points A & B with the jumper wires and hold
it about 1 inch above the table. Slide the adjustable resistor
(RV) control lever around slowly, you will hear a clicking sound
from the relay (S3) and buzzing from the whistle chip (WC).
Adjust the electromagnet height and resistor control lever until
the paperclip vibrates up and down on the table. The vibration
pattern may seem complex because it is due to two sources:
the whistle chip and the relay.
Adjust the electromagnet height and resistor control lever to
change the height and frequency of the vibration.
You can also replace the 10K
Ω
resistor (R4) with the
photoresistor (RP). Waving your hand over it will start or stop
the vibration.
Drop in
Straighten and
bend paperclip
Project #683
OBJECTIVE: To show how electricity can lift things using magnetism.
Relay-Whistle Photo Vibrator
Take a paperclip and straighten it out, bend it in half, and
place it into the electromagnet (M3) center. Connect the
electromagnet to points A & B with the jumper wires and hold
it about 1 inch above the table. Slide the adjustable resistor
(RV) control lever around slowly without covering the
photoresistor (RP), you will hear a clicking sound from the
relay (S3) and buzzing from the whistle chip (WC).
Adjust the electromagnet height and resistor control lever until
the paperclip vibrates up and down on the table. Then wave
your hand over the photoresistor. The vibration pattern may
seem complex because it is due to three sources: the whistle
chip, the relay, and the photoresistor.
Adjust the electromagnet height and resistor control lever to
change the height and frequency of the vibration. Covering
the photoresistor stops the vibration.
Drop in
Straighten and
bend paperclip