What the Fridge Door Detector Alarm does is to detect whether there is some ambient light in the food compartment of your fridge or freezer.
This happens when you open the door and the Fridge Door Detector Alarm system senses some light that may be coming from the bulb light in the fridge or from the door opening itself.The Brain
I use an ATtiny85 microcontroller which is easy to program with an Arduino if you have one ;) Than you can write the code that will suit your needs perfectly - for example one may want to hear the buzzer 2- seconds after opening the door ... or maybe 45 or 2 minutes - you decide!
Using a microcontroler minimises the use of external elements which saves you time and cost!The Components
- ATtiny85 microcontroller
- Arduino Uno
- Prototyping board + wires
- Plastic box
- 180 kOhms resistor
- 0-100 kOhms variable resistor
- LDR - light dependent resistor
- Empty PCB to solder the schematic
- Board holder for the ATtiny
- Soldering iron
- Double sided sticky tape
- Cable cutters and knife