Here is an ultra simple Arduino Night Alarm project wired around a handful of inexpensive and easily available components. One advantage of using Arduino as a security system is the flexibility!

It combines an Arduino-compatible processor with a light sensor, a temperature sensor, a 3-axis accelerometer, a joystick, a set of pushbuttons, a slider, an RGB LED, and a buzzer.

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 ?

We wonder if it would be better to place the breadboard inside the jack-o’-lantern and carve out a couple of holes on top for the PIR sensor’s wires to come out of.

Once you get the alarm set up, it’ll sense movement near the Arduino, snap a picture, then send it over to you using If This Then That. All you’ll need is an Arduino Yún, PIR sensor, a USB ...

Present consists of just a PIR sensor and Arduino in a 3D printed enclosure to snap onto your monitor.