A physical version of the game "Keep Talking and Nobody Explodes". Not a real bomb.

The general plan is for each module to contain an ATmega328p which will handle running all of the local I/O and communicate with a controller module (also an Atmega328p).

Many modules need to act as an I2C master to display devices or sensors, and an unfortunate number of display devices have locked I2C addresses. This means that I2C isn't feasibly a possibility for intermodule communication. Desiring a solution that didn't require running a dedicated wire from each module to the controller module, I opted for a multidrop serial bus.

The downside of a multidrop bus is that some form of arbitration is needed to stop bus contention. This is solved by the DSerial library I wrote for this project. The DSerial library implements a layer on top of any Arduino Stream interface. The DSerial library operates with one master and many clients and in addition to managing bus contention, it makes a best effort to guarantee that each message will be delivered to the desired client exactly once. To this end, it implements message-level parity checking, a pre-defined number of retries upon failed delivery, and can determine which clients are alive on the network.

Currently DSerial has two major limitations:

• Due to being comprised of entirely non-blocking calls, it requires whatever is using it to periodically and continuously call the doSerial method.

• It currently only allows the transmission of bytes with values between 0x01 and 0x7F inclusive. Future implementations will hopefully allow for the transmission of null bytes and bytes above 0x7F.

Common functionality across modules has been extracted out into the KTANECommon library. The library handles the sending/receiving of strikes, solves and configuration data between solvable modules and the controller module. The library also handles the controller waiting for modules to setup and the modules easily querying various aspects of the configuration data. The KTANECommon library suffers from the same upside/downside as the DSerial library in that it requires the code to periodically and continuously call the interpretData function.

A template for modules can be found here.

The current iteration of the hardware is Version 1. V1 consists of one controller module and up to five swappable, playable modules in a suitcase as an enclosure. The modules connect to the main bus through directional male/female 4 pin plugs intended for LED strips. The major limiting factor imposed by V1 is the 1.25" height limit on user interface protrusions needed to allow the case to close.