A large button, one of four colours (blue, white, yellow, red), with one of three words printed on it (abort, detonate, hold). The button is under a protective cover that flips up. Next to the button is a strip that lights up with one of four colours.
Disarming rules depend on batteries, lit indicator labels, and/or the countdown timer.
Implementing as in Original Game
It might be possible, but I can't find suitable parts.
In order to be affordable I'd need a switch with replaceable button faces, or a few sets of buttons that can be plugged in and out of a socket. I haven't been able to find anything like this (certain NEMA industrial controls looked promising, but too expensive), so I'm going to call this "impractical" unless I come across the right parts.
Use a single translucent button, with RGB backlighting to provide different colours (see this or this for example). Use an RGB backlit LCD below the button as a combined alternative to the printed words and coloured strip.
This would be relatively cheap and easy to implement. Player experience would be very similar to the original module. Installation and setup would be entirely automatic.
Use an LCD key to replace the large button and printed word -- E3 keys, screenkeys, or similar. A separate RGB LED panel would be needed for the light-up coloured strip.
This would be more expensive and harder to implement. Player experience would be similar to the original module from a gameplay perspective, but the small key with low-ish resolution display would be a poor substitute for the original large button and clear printed text. Installation and setup would be entirely automatic.
Implement alternative 1 unless suitable button hardware can be found to match the original module.
Three to six wires, of various colours. Wires are freely accessible, and run horizontally between two columns of connectors. One corect wire must be cut to disarm the module.
Disarming rules depend on a serial number sticker elsewhere on the briefcase.
Implementing as in Original Game
Could be implemented identically, though I'd settle for pulling the wires out instead of cutting them.
Effort and Cost
Hardware could be as simple as two rows of breadboard headers and a microcontroller. Costs a few pennies.
Software would be quite simple. Interrupt on signal edge during the game, check that the correct wire was removed, signal success. Signal failure if the wrong wire is removed, a wire is removed after the success state, or a wire is connected. Some logic to debounce signals. For the installation and setup phase, monitor connectivity and report this back to some GUI.
Identical to the original game during the play phase.
During the installation and setup phase, the software helps verify that the correct connections have been made. The only manual verification is making sure the correct colours of wire are used.
Additional software and hardware could be added to indicate which connection needs to be made next -- extra LEDs that light up next to the correct sockets. Minimal extra cost and effort.
Implement as original module, with minor additions to aid in setup.
There's no point continuing this project if the modules can't even be implemented in the real world. So the first step is to figure out whether this is possible.
Will need to consider the following for each module:
Can it be implemented as in the original game? If so:
Will it be practical in terms of cost and effort?
What will the installation and setup experience be like?
If any of the above is a problem, what practical alternatives are there?
Will they compromise the original game's mechanics?
How will they change the player experience? This covers aesthetics, feel of buttons or other inputs, change in the kinds of actions the player needs to perform, change in the speed of solving the puzzle.
Ideally you would create or choose a puzzle via some nice graphical interface. You'd be prompted to install the correct modules in certain places, and do any other physical stuff that's necessary -- it's probably just wire modules that need extra setup.
The installation process should be quick and easy. During the installation process you could be guided by the GUI, and maybe the briefcase too? Eg "put a button module in the illuminated bay". Wire modules can check that wires have been set up correctly by checking for continuity, then feeding back to the GUI.
After modules are installed, they are programmed with whatever they need for the chosen puzzle. Wired programming would be lame, go wireless!
After the briefcase has been set up and programmed, its ready to be played. Grab friends, get ready, start the countdown. Countdown is started via the GUI or a small button on the briefcase?
The briefcase should be freely movable during the game -- no wired power supply or other connections. While playing, the look and feel should be close to the original game -- similar sounds, buttons/switches/whatever, lights, appearance wherever possible.
Winning and losing should be obvious, fun. Some satisfying audio on defusal, appropriate dimming of lights, etc. Losing could be funny -- opportunity to troll people with smoke, firecrackers?
Affect on Design
Given the experience described, certain requirements or goals suggest themselves.
Need a graphical interface for puzzle selection, installation, programming. Could be on briefcase, but this would likely be small, underpowered, ugly, take up room that modules should be using -- definite no. Could be a PC program, but this limits portability slightly. Ideally then would have a tablet app, which strongly indicates using Bluetooth for connectivity. Still, would probably develop something on PC first, for familiarity and ease of debugging.
Replaceable and freely movable modules implies modular design (duh), both in terms of mechanical and software design.
Pluggable modules with exposed bits -- ESD protection!
Easy and quick installation makes mechanical design important. The original game has up to 11 modules in a briefcase, so even a little time spent on each quickly adds up. A couple of screws per module would be simple design-wise, but seems like that would be slow-ish and fiddly. Maybe a few clips instead? Something clever with magnets? The modules mustn't become disconnected accidentally during the game! Needs much more thought.
Possible to have multiple of the same kind of module in a briefcase, so modules need some kind of identification/addressing system. Bonus points if you can plug any of those multiples into a slot and have it "become" the correct one, rather than needing to put a specific piece of hardware into a specific place. I.e. for modules of type A, any of the instances A1, A2, or A3 could go into briefcase bay X.
If we want installation to be guided by the briefcase, it requires some intelligence that is a permanent part of the briefcase.
Wireless programming and a freely movable briefcase requires batteries.
The briefcase and modules need to be rugged. They're going to get flipped around, bashed, poked, dropped etc.
Indicating a win or loss requires a speaker within the briefcase, maybe some extra lights etc.