Nuts & Volts Magazine is written for the hands-on electronics hobbyist, design engineer, technician, and experimenter.
Fridge Door Alarm using an LDR
Light Alarm Circuit with LDR
Roger Secura Nuts & Volts Magazine
Refrigerator Alarm Circuit
Fire Alarm Circuit Using IC 555 and Thermistor
How to Make a Refrigerator Door Open Alarm Circuit
Nuts & Volts Magazine
Low Voltage Alarm Circuit
Fridge Door Detector Alarm : 13 Steps (with Pictures) - Instructables
How to make a Fridge Door Lock Alarm using the 555 Timer IC
Fridge Door Alarm Circuit Circuit Diagram
Temperature Alarm Circuit