This is my personal bread and butter. I've worked with Arduino, Teensy and the Raspberry Pi for the better part of 5 years now. The main electronics criteria is to be low budget but high results. With that in mind we're leaning heavily on the side of using what we already have. Luckily, I have a nice collection of parts. Starting with a general layout plan, I'll explain each part below;

Raspberry Pi

The Raspberry Pi is the go-to product for hobbyist projects. It's both cheap, small, easy to get running, exceptionally versatile and powerful. It's a fantastic product that for us will be employed as the "brains" of the coffee table. It will be running the reactive web server that will provide the main interface to both the train controls and also the lighting as well as controlling automated tasks. 

Sprog DCC Controller & DCC Trains

The Sprog DCC controller will be handling the DCC Train track controls. We're using the Sprog II which is a DCC controller in a very nice compact package. It uses the DCC protocol to control the trains on the track that can be individually addressed and controlled. The raspberry pi will pass commands to the sprog via USB and a custom python script which will allow us to control the trains via the web interface. 

Teensy Microcontroller

Currently undecided "which" Teensy microcontroller to use but these devices are all essentially Arduino compatible fast prototyping microcontrollers with a variety of interfaces. The Teensy will be our effects manager handling; the ambient RGB strip lighting, LED lighting for individual parts as well as possibly servos for track switching and manual input buttons for a secondary tactile control method

NEO Pixel Strip

There are a variety of cheap controllable LED lighting strips now available. We'll be using the strip lighting to provide an "ambient" lighting effect within the layout. The current plan stands to integrate this lighting into the top section of the table so it's casting down onto the track layout. Everyone loves a bit of RGB lighting.

LED Lighting

LEDs can add a really nice layer of visual effect to a train layout. We plan to integrate LEDs into the housing and there are off-the-shelf cars and street lighting that contain LEDs we can use for added effect

Manual Switches

Currently under-thought about. It could be nice to have some tactile switches that can be used to control the coffee table effects. A potentiometer for speed and various buttons for lighting and sound effects would create a fun interactive control for the kids. 

Servo Track Switch

PSU Management

Power is another factor that will be thought out as we finalise more parts of the design.  DCC requires in the range of 12v-16v DC while the Pi and Teensy run off of a standard 5v. Using parts we have, I'm hoping a laptop power supply may suit the power requirements once we settle on the current draw of the system. 

USB Power Ports

A coffee table that can charge your phone? Yes please!