The Hidden Hardware

 

 

Logic Board

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full sized image.

This is the heart of the computer control system.   It receives and sends information from a PC via a parallel printer interface.  Provides registers and ports for other circuit boards, a real time clock module for scan timing, and pulse points to enable/disable modules.

 

Sensor Array Board

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This board has 9 ultra-sensitive track sensor circuits that report accurate current and voltage measurements from their respective track sections.  Each circuit uses 4 op-amps, 2 voltage controlled oscillators, and extensive filtering.  Each circuit is also completely isolated by opto-isolators and DC to DC converters to allow op-amps to float when engines are run in reverse.

 

Power Control
and Switch Track
Drivers Board

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full sized image.

This board controls the speed and direction of the trains with 6 separate power supplies.  The train speed is controlled by pulse width modulation (PWM).  In layman's terms, PWM speed control means that power is delivered to the track in timed pulses.  To make the train travel slowly, the pulses are very short/quick - to make the train travel faster the pulses are widened.  This method of speed control allows for the engines to operate at very slow realistic speeds without stalling.   This board also has 18 SCR circuits that control the layouts 11 switch tracks.  These circuits deliver timed pulses to the switch track to prevent switch motor overheating.

 

Sound Board

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full sized image.

This board has 4  ISD100A Voice Record/Playback IC's.   Each IC stores 20 seconds of digital sounds that are stored in a non-volatile (permanent) memory.   I have programmed these with sound effects for the trains and the town.  Many of the sound bytes came from the movie "High Noon".  For example, the saloon occasionally exclaims "Well boys, what are ya gonna have?".  The computer selects when a sound will be played and where the sound will come from  (there are four speakers hidden inside buildings around the layout).

 

Waterfall Sequencer Board

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 full sized image.

This simple board has a simple purpose, to light four halogen lights, one at a time in sequence for the fiber-optic waterfall.   The speed and brightness are adjustable via controls at the front of the layout.

 

Waterfall Spaghetti

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 full sized image.

Here is how the four sets of fiber optics are fed into the base of the waterfall.  The sequencer driven halogen bulbs are inside the polished aluminum tubes.

 

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