This is a motion alarm.  The alarm sounds when someone enters the room.  An authorized fingerprint must be scanned to silence the alarm.

This is a motion detector based alarm;.  After arming the device, when someone enters the room and triggers the motion sensor, a buzzer sounds for 30 seconds or until an authorized fingerprint is scanned via the fingerprint scanner.  After 30 seconds a 90dB siren sounds, and continues to sound, until someone scans an authorized fingerprint, or until someone with a key turns off the device.


An LCD is provided, on which a menu is displayed.  After the device is powered on the user can do the following:


1) Arm the device (this gives you 30 seconds to exit the room before the motion sensor is enabled)

2) Enroll a fingerprint.  'Enrolling' means adding a fingerprint to the group of fingerprints authorized to silence the alarm.

3) Delete all enrolled fingerprints


Four buttons are present.  One simply resets the micro controller.  Two others are used to navigate up and down on the LCD menu, and another is used to select an item on the menu.


The breadboard portion of the Fritzing diagram is complete.  The schematic and PCB diagrams are not yet complete, and I'm not sure if they will be completed (by me).  Help understanding how to correctly create the PCB diagram is appreciated, as are all comments in regards to the breadboard diagram and the code.  This device would obviously need to be deployed within a hardened enclosure before it could be used in a real security application.



Atmel ATMega 168 (or 328).  Depicted in diagrams with a 168, but actually implemented with an ATMEGA328P-PU, with the Arduino bootloader present.

Fingerprint sensor

Siren (12v)

16 x 2 LCD

2 6AA battery enclosures (depicted with 2 9v batteries) deployed in parallel

Motion sensor

key switch w/ a key (depicted with a slide switch)

Active piezo buzzer

SPST relay

16mhz crystal


4 push buttons

two capacitors

12 resistors

1 Green LED

1 Yellow LED

1 Red LED

2 NPN transistors (2N2222)

1 terminal block

1 5v voltage regulator

2 10 uF electrolic capacitors

1 diode

hook up wire

400 point breadboard

12 AA batteries

ear plugs


More details on the construction of the device and the code that accompanies it will be provided shortly (assuming I can edit this description after it's created; this is my first 'fritzing' project).