EDIT: Made a version 2, which is slightly harder: https://www.dropbox.com/s/wqv32vzpy5ivz ... 2.sub?dl=0
I was a lil' bored, so decided to delve into circuits again. (Woo, enjoying a game for everything but it's main attraction of submarines)

It's a time bomb. In order to disarm it, you have to go full hollywood - snipping wires. No water pellets to destroy this circuitry. It's designed with all real-life limitations in mind. The only difference between this circuity and what might be found in real bombs is: This one needs no power to operate, and I've hidden the actual detonators and explosives so you can't access them, as that'd simply be too easy.

TL;DR you have between 49-99 seconds to disarm the bomb. I'll go ahead and explain the basics of bomb defusing;

1. You can stop the timer. This is the most obvious way, but it's also the hardest, because one unexpected/uncontrolled signal may trigger the bomb.

2. You can try to figure out the password, or even just guess it. It's 4 binary digits labelled A-B-C-D at the bottom. It's randomly generated each game. Guessing correctly will disarm the bomb. Guessing incorrectly will obliterate you.

3. If worst comes to worst (such as being past the minimum threshold of 49 seconds) what harm could cutting random wires do?

Anti-tampering measures are extremely hard to implement. The two main methods I used were:
-Using 2 of the more critical things and comparing them. If one is different to the other, then it's obviously been tampered with.
-Identifying a value that would always be the same as / different to another value, then use the wonder of XOR gates to make sure everything is going as expected.

So yeah, thats it. I just mucked around for a couple of hours to make this, enjoyed making it, and I'm curious whether anyone is able to disarm it or not.
(If you do disarm it, I'd be interested to hear how)

Download, incase you're curious (I mainly made it just cause I was bored and interested, but may aswell share it:) https://www.dropbox.com/s/0p6w6cbqpep3d ... l.sub?dl=0

Do you have a schematic?

Sir_Jay wrote:Do you have a schematic?

Of which part, exactly? I obviously couldn't look up 'how to make bomb pl0x' so I don't have a schematic of the entire thing. But the timer, for example, is just two sets of four J-K-PRE-CLR flip flops with their Q output connected to the next's J & K. The connector to the tens digit is an AND gate connecting to the first and last timers (1001 = 9) whose output is linked to all the proceeding CLK signals. If ye want to build that, just look up JK flip flop schematic, then connect them in the same manner. Voila.

If you expected it to be easy and simple to build, no, it's not.

Made a version 2, as the first one was (as a couple of people remarked) a little too easy. Not too much was changed, I just fixed all the safety checks that werent working as they were suppose to and added a new circuit, which is the new purple chip to the right. Whats it do? Who knows. So yes, it should hopefully be a *little* more difficult to take the 'obvious' disarming routes but honestly, it's impossible for me to make it hack-proof, and chances are that if you blindly cut a random wire the bomb isn't going to blow up, and you may have even prevented it from going off if you cut something important.

So incase anyone actually wants to try this, which I fear many will not as those who know circuitry are by far in the minority, I'll set some goals, as simply looping the timer is far too easy and doesn't necessarily 'disarm' the bomb.
1. Get the timer stuck on 00. - Suprisingly difficult.
2. Get the timer past 60, without blowing up - I couldn't manage this and I know the bomb inside and out.
3. Disarm the bomb. (See that little 'ARM' light? Get that to go off by itself) - Should be the first thing you try, really.
4. Find out the correct password. - I mean, I can do this within 10 seconds, but doing it without my knowledge of it would be difficult.
5. Stop the clock. - Pretty easy if you know what to look for, pretty hard if you don't.

For extra challenge I added a 'faulty' safety chip now aswell. Every 10 seconds, it has a small chance to outright blow you up. I didn't make it faulty intentionally, it just ended up that way and I decided to keep it like that for the challenge. Identifying it and disarming it should be super easy, though.

https://www.dropbox.com/s/wqv32vzpy5ivz ... 2.sub?dl=0

If anyone manages to achieve any of those goals, feel free to reply 'ere with a screenshot to brag and tell muh how you did it.