Introduction: Arduino Based Digital SAFE BOX

Hey guys! Do you have something that you want to keep safely? Something that needs to be kept away from unwanted intruders and privacy invaders? Well, I have a solution for your problem! Here's an Arduino based lock Safe Box

Step 1: Watch the Video

watch this video for step by step visual representation along with narration of steps.

Step 2: Designing

to get started with,

i created a full Scale model of actual vault on "AUTODESK's INVENTOR PRO " which is a 3D C.A.D. software for innovators like you and me.



after designing, i moved to the step of material selection.

for material, we have the best material for this application STEEL.

because i constantly keep reusing the modules and other electronic items, i choose to not stick with STEEL safe, as it will be quite a mess to store.

so then i choose Cardboard as it can be recycled once the project is done.



since we all know that cardboard is quite delicate and could break easily, so here i have used few small isosceles right-angled triangle cardboard pieces(26 in total, 3 per wall corner, 4 for the door corners) along with HOT glue to stick the faces of walls in each direction.



for the dimensions and other exact details, i am uploading my CAD files, download them for reference, if you don't have a CAD software, i will give you guys a dimension overview.

1. BOX volume

300mm x 300mm x 300mm (l b h )

2. Door Volume

200 mm x 50mm x 200mm ( l b h )



So, basically, the mechanical working of this project is similiar to a door, accept it has an electronic lock, which is controlled by a microcontroller.

Step 3: Gather the Material

Here's what you need

A. Electronics

1. Arduino Micocontroller Board.

2. 16x2 I2C (I-square-C)LCD

3. Solenoid Lock.

4. 4 x 4 Keypad.

5. Buzzer.


7. 10 kohm resistor.

8.12v 5.5mm DC male i/p jack

9. 12v 5.5mm DC female jack

10. Male-to-Female jumper wires

11. General Purpose Board .( else use a breadboard).

12. Soldering Iron.

13. few Jumper Wires.

14. IC 7805( Voltage Regulator)

B. Misc

1. Cardboard

2. Scissor

3. Box Cutter

4. Hot Glue Gun

5. Hinge

6. bolts( M3 20 mm long bolts with nuts)

7. Self Threading bolts.

8. Screw Driver Set.

please note

this is NOT a paid promotion of any company in any manners, you can use any similar products, all the links are found by simple google search.

Step 4: Making the BOX

to construct the BOX


1.Cut 5 peices of cardboard of size 300mm x 300mm.

2. cut 30 isosceles Right Angled Triangles for support.

3. Use Hot Glue gun to toss a coin sized adhesive to right stick the bottom face with left face using the small triangle support we cut in previous step. seal the entire edge using hot glue adhesive.

5. repeat the steps 2-4 till right, left, top faces are bonded together.

6. keep the back side open, we will need to access electronics and would need to glue front frame.

Step 5: Electronics.

here, i am using ARDUINO UNO.


1. connect the keypad pin


1- D9

2- D8

3- D7

4- D6

5- D5

6- D4

7- D3

8- D2


there is a small arrow marking on Keyopad to indicate pin1

2. Connect Positive of Buzzer to PIN D10 and Negative to Ground.


3.Connect 16 X 2 L.C.D. Display

Pin SCL tp A5,

Pin SDA to A4,

Vcc to 5V on Arduino ( Power Pin),

GND to Ground on Arduino (Power Pin).


4. Connection For MOSFET ( IRFZ44N)

source - GND of Arduino and 12V power Supply

Gate - Pin D13 Arduino

Drain - Solenoid negative.

10K ohm Resistor Between Gate And Source.


5.Connection to Solenoid.

Positive - +12V power ( i.e. Female DC 5.5mm Jack).

Negative - Drain of Mosfet.


6.Voltage Regulator (IC LM7805).

Vin - + 12 v DC 5.5 Female

Gnd - Ground and Arduino GND ( Power Pin)

Vout - 5V Arduino (Power Pin).

Step 6: Coding

Here, I have used 3 libraries, i.e.



and keypad

So in this code I stored the default pass code which is 0123 to the eeprom of atmega328p,

used conditional if else statement to check the entered password and open / close the lock accordingly.

also, i have assigned special character "#" to change the password, which will check if you have the current password and if current password is right, you can assign new 4 digit passcode.

also used lcd for Interaction, used basic clear set write commands of lcd, depending on conditions and at the end created a function called beep for indicating the buttons clicked at the end of the code..find the code in attached files.




EEPROM Library V2.0 for Arduino

Keypad library for Arduino

Step 7: Door

in this step, we will complete the door

1. cut 2 cardboard peices of 200 mm x 200mm .

2. cut 4 pieces of 200m x 50mm.

2.make slot for lcd.

3. mark holes for LCD, Solenoid, Arduino UNO.

4. use M3 x 20mm bolts with nuts to secure the LCD, Solenoid, Arduino UNO.

5. stick the right side, left side, top, bottom to front side using hot glue gun and cardboard triangles.

6. mount Hinge using M4 Wood Scews on the Right Side.

Step 8: Door Frame.

after finishing the door, we will fix the Door on the Door Frame.


1. Cut 6 Cardboard of Size 50mm X 300mm.

2. join 3 pieces of cardboard Strip using HOT Glue Gun.

3. Stick the CardBoard Stip 50 mm away from the Front of the box and stick it using hot glue and triangles for support.

4. make a slot of 20mm x 20 mm on another carboard strip to make a slot for lock. stick this parallel leaving no gap to the left side.

5. screw M4 wood screws on Right Hinge Support.

Step 9: Finishing


1.cover up the open space left by door using another cardboard piece.

2. use velvet texture paper to cover the internal volume of cube to give it a vault like feel and texture.

3. Install the back cardboard face to BOX.

4. remove the white paper on this cardboard by gently rolling and peeling the paper from the layer beneath.

Step 10: Conclusion

so in this DIY build, we learn a little bit arduino coding, we worked with the simplest arduino LCD display (I2C) and we made our own Electronic SAFE BOX, which can easily store anything from expensive jewelery to money.

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