Arduino Defuseable Bomb, Perfect for Airsoft Games! (with Timer, LCD, Keypad, Sound and More!)




Introduction: Arduino Defuseable Bomb, Perfect for Airsoft Games! (with Timer, LCD, Keypad, Sound and More!)

This is a project I made a long time ago, but decided to upload anyways, feel free to ask me about it!
The bomb has several features:
- Password input by keypad to arm the bomb
- Timer/count down
- Sound
- Flashy LEDs
- Defusing via the password
- LCD display
- Keypad
- Simple to edit and change

So to get started you would need:
- Arduino
- LCD (I used a 16x2 from sparkfun)
- Potentiometer for the contrast on the LCD 
- Keypad (again from sparkfun)
- Jumperwires
- Resistors for the LEDs (I used 330 Ohm)
- Piezo/buzzer
- LEDs

Step 1: Assembly

Connect the components as according to the circuit schematic

Step 2: Upload the Code

Upload the bomb project4 code to your arduino, and add the following libraries: Keypad, Tone, and liquid crystal to your libraries folder in the arduino folder

and now you're ready to use the bomb!

First edit the time in the code, to match your needs, then start the arduino and enter your desired password, then the bomb timer will start, and you can press the * to begin defusing the bomb, if you press a wrong key, pressing # will delete what you've written. If you write a wrong password, or the timer reaches 0, the bomb will "explode"!

Feel free to ask :)

11 People Made This Project!


  • Water Contest

    Water Contest
  • Creative Misuse Contest

    Creative Misuse Contest
  • Tiny Home Contest

    Tiny Home Contest

167 Discussions

Hey, I am having a issue with the LCD screen. When I turn it on nothing is being displayed on the screen, the keypad, LED's and buzzer work fine, when I enter the code and it start counting I am able to enter password again after the * and it is being defused or explode but the LCD screen itself does not display anything. I am including the picture of how the LCD is displayed


hi, have you found a solution i have your same problem.....the lcd makes only a long line like in your photos...

I may found the reason for the LCD to not work correctly.....

The schematics of the LCD does not show which order are the pins, if they are VSS, VDD, VO, RS, RW, E, D0, D1, D2, D3, D4, D5, D6 ,D7, A, K, or other way round... I will Re-solder them and we will see if it helps.

Hi, firt of all thanks! but i have a question, what if i have a 4x4 keypad? how this change my connections and code ?


7 weeks ago

HI. there is a Bug in the code!!! The time progressively going down but always avoids the whole minutes like "06:00", "05:00", "04:00" ... it is posible to solve this problem???

Hi, in case I wanted to add an option to change the time, I had thought to insert an interface with the selection of the time, inserting it with the keypad, all this before entering the code, is it possible?

Hi! It worked! It's a great project, thank you! I changed some code
lines and used it in an escape game. I am a teacher and some colleagues
on a website calles S'Cape are asking for a tutorial. I told them I was
not the great inventor of the project and that I would ask you if you
were ok with it. Please let me know.

Hi. How do i wire the LCD if i have only 4 pins(gnd,vcc,sda,scl)? I have a small board on the 16p. Do i need a different cod? Pls help me.

1 more answer

Replace your LiquidCrystal.h library with LiquidCrystal_I2C.h that you can find anywhere on the net. Wire the SDA to terminal A4 on your Arduino and SCL to terminal A5.

Then add this to your code:

LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);

//LiquidCrystal lcd(7,8,10,11,12,13); // the pins we use on the LCD

You may need to alter the LCD commands to something like:



lcd.print("Code: ");

A bit of reading on the net will also help out, but that should get you going for now :-)

hi, how to Connect This type oferta display? it Has some addons: potentiometr, gnd (-?), vcc (+?) , sda, scl. Also led and power with jumper on it. how can i adjust it to the shame.

1 reply

Hi. i'm having the same LCD. Did u have any luck?


"menu principal was not decleared in this scope"- how to fix it?


Question 6 months ago

"menu principal was not decleared in this scope" ----------how to fix it?

I keep getting a exit status 1 message when I upload. Do you know how to fix this?