3THE COOKIE JAR ALARM
THIS ALARM BUZZES WHEN IT SENSES LIGHT.
THE CIRCUIT DIAGRAM
THE PARTS LIST
PART |
VALUE |
DESCRIPTION |
LDR |
200 kΩ |
Light-dependent resistor (photoresistor) with around 5 to 10 kΩ resistance in light and 200 kΩ or more in dark |
Q1 |
BC547 |
Any general-purpose NPN transistor |
R2 |
1 kΩ |
Standard resistor |
Buzzer |
|
Active buzzer that works with a 9 V battery |
ABOUT THE CIRCUIT
Do you want to keep people from stealing cookies from your cookie jar? Or keep spies from snooping in your treasure chest? Then this circuit is for you. ...
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