Fridge Alarm with 4060

Posted on Apr 5, 2012

This circuit, enclosed into a small box, is placed in the fridge near the lamp (if any) or the opening. With the door closed the interior of the fridge is in the dark, the photo resistor R2 presents a high resistance (>200K) thus clamping IC1 by holding pin 12 high.

Fridge Alarm with 4060
Click here to download the full size of the above Circuit.

When a beam of light enters from the opening, or the fridge lamp illuminates, the photo resistor lowers its resistance (<2K), pin 12 goes low, IC1 starts counting and, after a preset delay (20 seconds in this case) the piezo sounder beeps for 20 sec. t

Leave Comment

characters left:

New Circuits



Popular Circuits

Stereo balancer
Audio Metal Detector Schematic
Understand the 74HC595
sensor Arduino analog signal read problem
flipflop What happens when theres no specific input variable on a logic diagram using a JK flip flop
capacity Computing Current from known Capacitance and Time to Charge to Known Voltage
1.2GHz VCO With Linear Modulation circuit using MAX2754
Frequency Multipliers
Nathans Z80 Project Mark 2
Motorola Mitrek conversion to repeater or link
A stator coil connection
Diamond differential amplifier circuit input
Electronic sound control flooding imitation circuit design
High-rise residential walkway lighting control circuit
Differential amplifier circuit