By reading different values from the sensor, we can detect if is it light , dark or a value between them. Another element that we are going to use on this experiment is Piezo Buzzer. So what is it ?

In the microcontroller era today, Arduino is more than just a tool ... is used to measure the light level. The alarm system is triggered when a “Logic High (H)” level signal is detected at its sensor ...

If you want to keep an eye on your home—whether you're worried about burglars or just worried about the dog getting into places it shouldn't—this super simple DIY alarm will send you an SMS ...