Crosstalk

The mission statement of Crosstalk is that we would like it to bring back the joy of tinkering, designing things from near-scratch, and taking one's time with something, all while letting people connect and collaborate. We don't see that much anymore in computing.

Crosstalk is a printed circuit board builder and simulator that lets players construct cities out of electronic components, all of which follow electrical rules, the results of which players will have to deal with to maintain the city's operations. It supports a networked mode, in which one either collaborates with other players (party submode) or competes against them (adversarial submode). Cities can be shared via the Workshop.

Cities built in Crosstalk represent structurally valid PCBs, which, combined with physical simulation, means that there's an educational element to playing. It also means that cities designed in Crosstalk can be fabricated using standard and widely available PCB fabrication and assembly services, and as such, brought into the real world. One could design a fully functional microcontroller board in Crosstalk and have it fabricated and assembled using a PCBA service without additional setup or utilities. One would take the Gerber, drill, and pick-and-place files and the bill of materials from the export and send these directly to a PCBA service.

Theory

Buildings represent electronic components; roads represent traces; metro tunnels represent vias. Every PCB design element and principle has a parallel in Crosstalk. Learning to play the game teaches, in effect, PCB design. The game comes with a professional component library that consists of 75 hand-picked components and their metadata.

What happens in and around the city is computed using Maxwell's equations, heat radiation, conduction, and convection, and many other principles. Many of these principles' standard methods of solving are integrated via an in-house finite-difference time-domain physics solver (for electromagnetics) and finite-volume/explicit forward Euler over a 6-neighbor face-flux stencil/discrete-ordinates radiative transfer equation/Newton cooling (thermodynamics), based on approximately 2700 A4 pages of theory.

Keeping the city up and running will involve several measures. One of those measures will be keeping its crime rate down. In Crosstalk, this means decoupling power pins of active components. Voltage changes outside of tolerance caused by current spikes are a very common occurrence that must be managed. Letting these voltage changes slide past unchecked causes brownouts and, in more extreme cases, physical damage. Placing housing units, which function as parallels to capacitors, around the city decreases the probability of petty crime and homelessness occurrence, which will, in turn, reduce the city's crime rate.

Sandbox mode

Sandbox mode is the default Crosstalk experience. One chooses a PCB size, difficulty (which scales starting funds and the degree to which nature is unrelenting), and starts building. As one builds, one contains oncoming trouble while staying solvent. Players can build anything from a town to a megacity. Under the "Easy" and "Medium" difficulty settings, pin attribution will not be enforced, so as long as buildings are powered and interconnected based on their roles, they will be able to operate. If a player chooses the "Hard" difficulty, the player will have to use specific pins for specific things, such as wiring power in via VIN, outputting it via VCC, grounding via GND and COM, looping back voltage feedback via FB, and so on.

Networked mode

Party submode

In this submode, one can team up with others over Steam Networking and manage a city together. It is structurally identical to Sandbox mode, but with networking enabled.

With larger designs, managing nature, the physics of electromagnetism and electricity, becomes complex, so players will need all the additional help that they can get. One can be joined by up to two other players.

Adversarial submode

Here, players compete against other players. One side maintains the city; the other, playing as nature, wreaks havoc. The city didn't manage its crime rate? That's an opportunity for the adversaries to strike.

Each side is able to play with up to 3 players at a time, resulting in a maximum total of 3 vs. 3 players.