Introduction: How to Defuse a Time Bomb Game

About: I like to make things.

This idea just came to me out of the blue. I couldn't really find anything quite like it. The original idea was much more involved, so this is a simplified version of the game.

This is a "time bomb". You have to defuse it before the clock counts down. It uses the accelerometer, sound detection, touch sensors and more to make it difficult to defuse.

Step 1: Circuit

This is another perfect application of the Circuit Playground Arduino board! We're going to make use the built in accelerometer to detect if the bomb is upside down or not, or bumped to hard. The microphone is used to detect too much noise. We'll also use the neo pixels to indicate how much time is left in addition to the countdown. Finally, we will use the built in touch ability.

The quad alphanumeric display is designed to fit on top of a feather arduino, but its perfectly usable without. Simply connect the power and ground, and the SDL and SCL to the Circuit Playground.

Another nice trick we are employing here is using Play-Doh to simulate the explosive. There's no Play-doh in Fritzing so you just see wires. Play-Doh makes a decent conductor due to its water and salt content! So the Arduino can detect if the clips are connected or not, through the grounded Play-Doh.

Step 2: Parts List

Circuit Playground (

Quad Alphanumeric display (

Aligator clips (



box (approximately 5" x 4")

4 AA battery holder

Play Doh

4 resistors (around 220Ohm)

Double sided tape or glue


Step 3: Container

Any suitably sized box will work. I knew there was a reason I kept this nice container that my wallet came in. Its just the right size, 5" x 4".

Cut a piece of cardboard to just fit inside the container. Everything will be mounted on this so it can be removed easily.

Step 4: Attach Components

For the alphanumeric display, cut a rectangle into the cardboard and push it through from underneath. The circuit board will press up against the underside. A dot or two of hot glue on the top will hold it in place. Attach wires to the four pins (3v, gnd, SDA and SCL) and pass them through to the front side with a hole. Please see for assembly and pin guide for this module.

The battery holder is secured to the backside with some double sided foam tape. I used the tape because it adds about a 1/16" gap between the battery and the cardboard. I poked another hole for the wires to go through.

On the opposite corner to the battery, glue a small strip of cardboard. This will support the whole thing along with the battery holder, it also will hold the Play-Doh in place.

Push the Play-Doh into place, and then insert the four resistors into the Play-Doh and into the cardboard. Use a drop of hot glue on each resistor to hold it in place on the cardboard.

Back on the top side, cut a finger hold and a tab to fold up. This is what you will use to remove the bomb later.

Step 5: Code

Step 6: Instructions and Cover

Print out, cut and attach the instructions and labels. I used double sided tape.

Here is the text for the instructions attached to the inside of the lid:

So you’ve got a time bomb (sorry, we lied on the cover…)
Congratulations! Or maybe not.. You are the proud new owner of a time bomb. If the clock is already ticking down, you probably don’t have much time left.

If you would like to avoid the mess and fuss of an explosion, you may be able to defuse this bomb before the time runs out. Please read on if this is the course you wish to take. And good luck! Let us know how you do (if we don’t hear from you, we will assume it did not go well).

You may have noticed the circular array of lights on the main board. They will be lighting up one after another. When they are all lit, the bomb goes off. We probably should cut down on the verbage due to your lack of available time, so, let’s get to the point.

The first thing you need to do is carefully remove the bomb from the box. It is very sensitive so don’t drop or bump it. For further instructions, locate the defusing instructions on the top of the bomb.

For the two pages attached to the top of the bomb:

Page 1:

Slowly flip the bomb over. You’ll see four coloured wires with clips. You must remove these in order. Do it quickly, do it quietly.
White. Blue. Green. Red.

Now reconnect them:

Green. White. Red. Blue.

Slowly flip the bomb back over.

Page 2:

Now push the right button on the circuit board. Flip the middle switch. Then push the left button. The lights will flash in a color sequence. You must repeat this sequence by touching the same colored clips. Carefully place the bomb back in the box and close the lid.

Congratulations, you have successfully defused this bomb! If you are still reading this, however, you probably haven’t put the lid back on. Please do so before the time runs out!

The box lid cover:

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