Hidden Wall Outlet Safe (w/Arduino Lock)




About: Hi I'm Angelo! I am a college student taking my engineering majors in BS-EE/ BS-ECE at the DLSU. I use my course as an inspiration for making my current projects! I've been posting projects here ever since I...

Stash your valuables where no one will ever suspect. Wall outlets are perfect for stashing valuables since you have tons of them at home. You must be crazy enough to search every household outlet for a secret stash. Probably, no one would even think of searching outlets! :)) BTW, it requires a digital key, such as an Arduino, to open the hidden outlet safe.

The Super Secret Key (a.k.a Suicide Key)
The vault features a key that no one would be crazy enough to insert. That's by plugging a 3 wired prong directly to the outlet! Talk about High Voltage suicide! The lock can only be opened by connecting an Arduino to the servo's pins (located in the outlet). Don't forget, we are using a dummy outlet so it's completely safe since it's not connected to the power-lines. 

How Do You Open It:
Plug your DIY 3 pin cable from your vault to your Arduino (a.k.a Suicide Key) then connect your Arduino board to your PC (via USB). Upload the codes then press "CTRL + Shift + M" to access Serial Monitor. Enter "O" to open vault and "C" to close the vault's electronic latch. You can also open this by making a 555 PWM generator.

Influences & Inspiration:
This is probably another déjà vu experience to all Breaking Bad fans. You guys probably remember the scene when Walt hid the ricin capsule behind an electrical outlet during the "Live Free or Die" episode.

Tips & Reminders:
My 2nd version gave me a hard time since all of our wall outlets are embedded in solid concrete. Drywalls are easier to work with since it's easier to cut/ puncture. If you need a larger vault, multi-standard outlets and European outlets are bigger in size. This makes them much more ideal for stashing more stuff in one place. 

Watch This Top Secret Vault In Action! [Take that Walter White! :D]

Teacher Notes

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Step 1: Tools & Materials

Parts & Materials:
- Cheap AC Wall Outlet (w/ Safety Covers)
- Arduino UNO (w/ USB Cable)
- Mini Servo (Tower Pro SG90)
- 3 Pin Long Female Header
- Small Hinge (w/screws)
- Super Glue
- Wires

Tools & Equipment:
- Soldering Iron
- Hot Glue Gun
- Cordless Drill
- Rotary Tool
- Metal File
- Multitool

Step 2: Disassembling - Saving Some Space

Get your mini screwdriver and disassemble the outlets. This is done to save space inside your vault. Be sure to leave the safety mechanism in tact, this hides the servo's plug from being seen.

The safety mechanism needs to stay still. Use superglue if necessary. 

Step 3: Removing Protruding Objects

If any protruding objects are present, cut them off by using your trusty rotary tool (Dremel).

Step 4: Installing the Hinge

Disassemble the wall outlet (removing the cover) then screw the hinge on. 

Step 5: Making Way for the Hinge

The hinge requires extra space in order to turn 90°. Get your metal file and file off the excess plastic.You can now screw the hinge on your wall.

Step 6: Epoxy the Servo (Lock Mechanism)

Glaze the servo's bottom with epoxy and superglue, go crazy! LOL :)) 

Hot glue the servo's 3 pin plug on the wall outlet's safety mechanism. 

Step 7: Grinding the Terminal Box

Measure the distance of the servo's arm. Transfer the measurements to the plastic terminal and grind off some plastic for the servo's arm to latch on something. 

Be sure to grind it in a slightly slanted manner. This helps the servo's arm to have a better grip on the terminal block. 

Step 8: Establish a Connection With Your Servo

1st.) Make a 3 pin male plug - for connecting to the servo (electronic lock mechanism)
2nd.) Follow your servo's datasheet and connect the wires to the proper Arduino pin. 
3rd.)  Yellow Wire - To Digital Pin #9
4th.)  Brown Wire - Ground Pin
5th.)  Red Wire - 5v Pin

Watch the video for more detailed instructions :D

Step 9: The Arduino Codes

1st.) Download the codes below then upload the sketch/ codes to your Arduino
2nd.) Press "CTRL + Shift + M" to open the serial monitor
3rd.) Enter "O" top open latch - "C" to close latch

Suggestions, Tips & Tricks:
1st.) Use tact buttons + digital pins, instead of using the PC's serial monitor.
2nd.) Add a auto-lock delay for the servo to close automatically after opening.

The Raw Codes (if you are too lazy to download the sketch):

//Coded By: Angelo S. Casimiro (a.k.a ASCAS)
//Copyright Rule Applies - Attribution Non-commercial Share Alike (by-nc-sa)

//Press "CTRL + Shift + M" to access serial monitor
//Enter: 'O' To Open Lock - 'C' To Close (not case sensitive)


Servo myservo;
char gar;
void setup() {
myservo.attach(9); // Connect Servo To Pin #9
Serial.print("Enter: 'O' To Open Lock - 'C' To Close \n");
void loop() {if(Serial.available()){gar = Serial.read();Serial.println(gar);Serial.println("\nEnter: 'O' To Open Lock - 'C' To Close ");delay(1000);}

if (gar == 'c' || gar == 'C' || gar == 'close'){ //If "C" is entered, close the latch
/*myservo.write(150);delay(5000);  //Command servo to auto-lock after 5 secs.
[Remove this comment tag for Servo Auto Lock Code - Suggested by: marhar]


else if (gar == 'o' || gar == 'O' || gar == 'open'){ //If "O" is entered, close the latch



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    29 Discussions

    ASCASandrea biffi

    Reply 5 years ago on Introduction

    Thanks! Great suggestion BTW. I'll try to go our local hardware store. I hope I can find a hidden hinge there :)) fingers crossed!


    3 years ago

    The idea is
    really cool, but the accomplishment is terrible

    1) You
    don't need your arduino clone to do that, you are using just 2 pins while the
    arduino provides 14/6 pins, it could be easily done with Attiny13 which costs
    even less than your fake-duino, and requires less space.


    a) You need
    another microcontroller just to open it? It would've been easier if would just
    put a simple dc motor and power it directly through your "secret"

    b) The
    microcontroller needs to be connected to the pc, ok hold on, this is bad. Yes
    you could program your controller to just say one thing again through serial
    port, but you didn't provide me with this information :)

    3) if you
    want it to be opened and closed by exact word you can't just use some square
    wave generator, that's not how that works *see example below*7

    But anyway,
    i think the idea (even although you're not the first who come up with this) is
    not that bad, it could be worse. All i
    wanted to say is: i'd've done it in completely different way. Keep up


    3 years ago

    Hay ASCAS bro can you make a air purifying machine


    3 years ago

    Would there be a way to implicate the Bluetooth chip to make it phone code activated insteadbof using a key?


    4 years ago

    you are the master mind brother


    4 years ago on Introduction

    I'm a beginner with arduino. Is there some way to connect a regular DC motor to the arduino instead of a servo? Sorry, but when it comes to arduino circuits, I'm lost.




    Reply 5 years ago on Introduction

    I disagree; there is no connection to the mains involved, it is just a type of wall mounted safe. In fact, if you Google for "wall socket safe" you can find commercially available safes like this with the earth pin used as a keyhole.


    Reply 5 years ago on Introduction

    Agree with chaydgb, but UK sockets are fixed in place with two obvious screws - you'd only need to unscrew those to get access. I can't see how the US socket is fixed but there must be accessible screws?

    real inventer

    5 years ago

    I tried this it messed up my electricity and I had to pay 452$ to get it fixed


    5 years ago on Introduction

    this is rather nice, shame the outlet is a dummy though, then people like me who always carry a voltmeter could find your stash rather quickly.

    Excellent idea !! I am looking forward to your project, which may
    update further and a great project to complete the knowledge of home
    automation. Please visit alternative source: www.utsource.net


    5 years ago on Introduction

    Very nice! You might change your sketch:

    while (1) { move to open postion; delay 2000; move to closed position; delay 2000; }

    Then you won't have to open the monitor window to specify open/close.

    2 replies

    Reply 5 years ago on Introduction

    Great idea! I haven't thought of using a delay to auto close the servo. You just gave me an idea to connect an IR led to determine whether the door is shut and ready to close :)) Thanks for the suggestion! I'll add the code to the ible.

    BTW, I'm a huge fan of your quadcopter! I bought most of my parts from dx.com, luckily I was able to purchase all the parts for $89. All that's missing is the "flight control module". What's the best budget "flight control module" can you suggest? I'm excited to see this thing fly but I'm stuck with a $110 budget.


    Reply 5 years ago on Introduction

    Most excellent, I'm looking forward to your update!

    The Flip 1.5 is a really great flight control board that is very affordable (US$15).


    5 years ago on Introduction

    Did you took into consideration what would happen if someone unaware connects a regular plug into your "keyhole" socket?
    I'm wondering if the plug could damage or push in the 3 contacts leaving you not able to connect the arduino to the servo.


    5 years ago on Introduction

    great idea, but yeah I agree with the remark abt the police. They will tear yr house down if they think it is necessary. Besides, they have dogs that can sniff money