Coffee Table #3 Design


Note: The links on the left side of this page and the other Model CT-3 pages will take you to detailed information about the new coffee table's design and construction.

The electronics for Coffee Table #3 consists of a freestanding touch-screen Tablet PC, various off-the-shelf model railroad controller and sensor modules, a few custom-designed circuits, and various power supplies. In other words, Coffee Table #3 is similar to the Test Track, except that the coffee table has more of everything.

The majority of the electronics, except for the Tablet PC and power supplies, are produced by CTI Electronics.

Electronics Packaging

All electronic equipment except for the Tablet PC is located under the layout in the base of the coffee table. Most of the circuits, including power supplies, are mounted in a wooden “equipment box” that is fastened to the inside of the table. Some of the smaller electronic modules—primarily the special effects modules—are mounted on the underside of the layout, itself, or in the tunnel. The electronics in the equipment box are connected to the layout via four 40-pin extra-long computer cables. Communication between the electronics and the Tablet PC is via a standard USB cable.

The photo below shows an exploded view of the entire assembly, including the lift mechanism that raises the layout to the top of the table. Note that the mountain top in the layout is open, exposing the tunnels and some additional electronics.

A closer look at the equipment box—with the lift platform removed—shows the arrangement of electronic circuits and power supplies (photo below). The electronic modules are mounted on two long white removable boards, while most power supplies are mounted underneath. Two small exhaust fans with aluminum ductwork can be seen on either side of the equipment box. Stereo speakers (black boxes) can be seen at the top and bottom of the photo, outside the equipment box.

The underside of the layout is shown in the next photo. The green Tortoise slow motion switch machine at the top of the photo controls the crossing gates in the layout's main town. Various Peco turnout motors (switch machines), and special effects controllers are scattered throughout the underside of the layout. At the bottom of the photo, the four green cable connectors can be seen, as well as the terminal strips to which they are connected.

More information about wiring and packaging of the layout's electronics is available here.

CTI Controllers and Sensors

The specific CTI modules used in Coffee Table #3 include:

  • Train Brain

    The Train Brain has 4 heavy-duty SPDT controllers and 4 adjustable sensor ports. The layout uses the SPDT controllers for turnout control and for track power control. The adjustable sensor ports are used to detect train derailments and to monitor the ambient light level.

    There is 1 Train Brain module in the coffee table.

  • Dash-8 (Train Brain-8)

    The Dash-8 has 8 heavy-duty SPDT controllers. The layout uses the SPDT controllers for track power control.

    There are 4 Dash-8 modules in the coffee table.

  • Switchman

    The Switchman has 16 medium-duty SPST controllers. The layout uses the Switchman for turnout control, scenery light control, and for special operating scenery such as flashing lights and grade crossing gates.

    There are 3 Switchman modules in the coffee table.

  • Sentry & Current Detectors

    The Sentry has 16 nonadjustable sensor ports. The layout uses the Sentry for detecting train location and direction. The Sentry ports receive the train location and direction information from track current detectors.

    There are 4 Sentry modules and 16 dual current detectors in the coffee table.

  • SmartCab

    The SmartCab is a programmable throttle that is used to operate the trains and the trolley. The coffee table is designed to run a maximum of 2 trains and 1 trolley independently and simultaneously.

    There are 3 SmartCabs in the coffee table.

Other controllers and sensors

Several non-CTI controllers are used for special effects throughout the layout. These include:

  • Custom-designed controllers for emergency vehicle lights and an operating drive-in theater.

  • Off-the-shelf controllers for fire effects (a fireplace and a burning building) and grade crossing lights/gates.

New special effects are being evaluated on a continuing basis. As recently as August 2014 two new Miller Engineering animated signs were being added to the layout.

Power Supplies

Eleven power supplies provide power to the layout.

  • 12 VDC regulated, 5 Amps: CTI module power

  • 5 VDC regulated, 5 Amps: Scenery Light power

  • 24 VAC driving a fast-recovery DC pulse supply: Turnout power

  • 13.5 VDC unregulated, 1000 mA (3 supplies): Track power input to the 3 throttles

  • 12 VDC regulated, 4 Amp: Lift Mechanism power

  • 9 VDC regulated, 1 Amp: Sound system power

  • Variable (set for 9 VDC) regulated, 1 Amp: Crossing Gate (Tortoise) power

  • 4.0 VDC and 4.5 VDC regulated supplies for animated theater and store roof signs

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