Fingerprint and Keypad operated Safe

The Fingerprint and Keypad Operated Safe contains a locking mechanism controlled by a fingerprint sensor and a keypad. Only by entering the correct password can one scan their fingerprint, which then unlocks the safe.


Jeffrey Z

Area of Interest

Mechanical Engineering


St. Francis High School


Incoming Senior

First Milestone

For my first milestone, I got the fingerprint sensor hooked up to the keypad and an LED. In order to get the LED to light up, I programmed it so that you needed to first input the correct password into the keypad, then pass the fingerprint sensor’s pattern recognition test.

Second Milestone

For my second milestone, I replaced the previously attached LED with a Servomotor and set up a locking mechanism. As my safe is secured by a swinging hook, I designed a locking system that held the hook in place, preventing it from swinging out. When both the keypad password and fingerprint are inputted, the attached servo pulls an extended rod over a ramp, sending the locking mechanism above the hook, thereby allowing the box to open.

Third Milestone

For my third Milestone, I


How it works

The Mini POV 4 is powered by a 4.5V source. The 100μF and 0.1μ F capacitors work together to stabilize the current and filter out noise. The potentiometer, also known as a variable resistor, controls the amount of current that flows to the microcontroller. When the dial is turned, the input to the micro controller changes, which changes the output (the LEDs’ blinking speed). The 2.2k resistors limit current flowing to the 3 transistors. Because the micro controller’s signal is not strong enough to communicate with the LEDs, the transistors amplify the signal. Each LED has it’s own 47 ohm resistor that prevents the LED from overheating. In between the resistors is a ceramic resonator which acts as the board’s metronome and makes sure that the LEDs blink at a consistent rate. The board also has two diodes to make sure electrostatic discharge does not occur. Electrostatic discharge is when static electricity is released when two objects come into contact. The diodes also ensure that the data being transferred from a computer to the POV does not get interrupted. Last of all, there is the USB type B port that allows the user to customize the image on a computer by using the Mini POV 4 software. Users are able to draw their own 8 pixel tall image and download it to their POV.

These are the instructions

Mini POV Schematic

Jeffrey Z. 2
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