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The Hidden Hardware
| Logic Board |
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| 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.
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| 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.
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| Power
Control and Switch Track Drivers Board |
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| 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.
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| Sound Board |
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| 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).
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| Waterfall Sequencer Board |
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| 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.
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| Waterfall Spaghetti |
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| 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. |