Defusable Clock

The Defusable Clock kit is NOW AVAILABLE FOR PURCHASE!



This may look like a dangerous device, but it’s really just an ordinary alarm clock — with a twist.









I thought it would be fun to build an alarm clock that looks just like the type of bomb that we always see in Hollywood movies. I certainly don’t know anything about how a real bomb might look, but in the movies they always have sticks of dynamite strapped together, a red digital readout, and a bunch of curly wires. Instead of just building an ordinary clock, I thought it should have a detonation sequence with a scary countdown just like in the movies. And why not make it “defusable” so I an try to stop the countdown by cutting the correct wire?





The Defusable Clock is a fully-functional alarm clock just like you’d expect (a normal beeping alarm, snooze alarm, etc.). But at any time you can press the big red button to start a scary countdown sequence exactly like bombs in Hollywood movies. There are 4 wires across the top of the clock. You have 10 seconds to choose the correct wire to cut: one wire stops the countdown and saves the day, two have no effect, and one will “detonate” the device immediately. These role of each wire is randomly assigned when the detonate button is pressed, so it’s a new challenge every time. Also, the wires are attached with screw terminals, so you can replace them easily. If you don’t want to actually cut the wires, you can just pull them out of the screw terminals if you keep the screws a little loose.

The microcontroller is an ATmega328 with the Arduino bootloader, so this clock is programmable with the Arduino IDE. The ATmega328 is certainly more powerful than needed for a clock, but this device has lots of inputs/outputs, and ATmega328 chips are now about the same price as the older ATmega168. It keeps very accurate time and requires a simple 9V “wall wart” power adapter. A special alarm mode lets you even use the countdown sequence as the alarm and require it to be defused when you wake up in the morning. What a stressful way to start the day!

We are going to offer this as an electronics kit later this fall. Only the electronics will be in the kit — nothing that looks like dangerous explosives! With some imagination, I’m sure you can make a great looking Defusable Clock for yourself, but don’t go scaring anyone with it, and don’t bring it anywhere near an airport, ok? The product page will have plenty of warnings not to use this kit for any evil purposes or get into trouble with your school, employer, or local law enforcement! There will also be a picture gallery where you can submit a picture of your clock after you build it.

UPDATE: the Defusable Clock kit is NOW AVAILABLE FOR PURCHASE!

I’m sure some of you will have some ideas and comments, so please leave them below. Keep in mind that this is no more dangerous than any other alarm clock, and yes, we have already spoken to a lawyer about all of this.

Here’s one more version I made using clay for plastic explosives:



