Voice-Controlled Lamp

Project Number: 72

OBJECTIVE: To turn a lamp on and off using the voltage generated from a photoresistor:

Description: Use the circuit from Project #71. Remove the photoresistor (RP) and connect the whistle chip (WC) across points A & B. Turn the slide switch (S1) on and clap your hands or talk loud near the whistle chip (WC), the lamp will light. The whistle chip has a piezocrystal between the two metal plates. The sound causes the plates to vibrate and produce a small voltage. The voltage then activates the music IC (U1) and turns the lamp on.