by Charles R. Hentz
On June 13, 2023, the GSV Train Club decided to build a night scene on the O gauge layout to better display our many lighted signs and buildings. This required the overhead fluorescent lights to be off during our regular open house sessions. A new system of four eight foot LED strip ceiling lights will illuminate for daytime but will be 0 to 10V dimmable to a low level for the night scene. Using ceiling clips, white 16 gauge line cords carrying 120 vac to each unit’s end was connected to the receptacle on the center beam controlled by the rear wall switch. Concealed behind the drop ceiling panels, a pair of low voltage dimming wires (18 gauge) in a gray cable enters each unit at the center. Dimming is controlled manually by a rotary potentiometer located at the rear under the double overhead trains.
The automatic system (Mega Arduino microprocessor) to control the scene is activated by a START push button on the new panel. A switch for AUTO/MANUAL dimming is on this panel. During AUTO control, the normal Maximum Level of the ceiling LEDS can be set by rotating the knob located inside the door of the panel.
Upon press of a start button on the rear control panel, the three minute show begins with the Ferris Wheel turning, the ceiling lights slowly dimming to night time level and the sound of crickets. After dusk, a flash of the lightning with a delayed clap warns of an approaching storm. After twenty seconds, the sound of gentle rain falling is heard for ten seconds. On the first series of lightning flashes by the ceiling LEDS, a clap of thunder will be heard and the Ferris Wheel stops. As the storm continues, two more series of random flashes and clap of thunder are heard. Then gentle rain slowly fades. As the lights slowly come up, you can hear the sound of crickets and a rooster crowing twice. After dawn, a man singing “Oh What a Beautiful Morning” ends the scene.
The arduino code incorporated a random number so that the number of lightning flashes(2 to 5), the time length of each flash and the time length between flashes are not predictable.
The Geeek Pi Serial LCD display module was used that allows four lines of twenty characters each on a blue background. Serial Communication with this display needed only four wires and easily showed the progress of the program. The maximum and lowest light level as well as the current light level were also on the display.
When we attempted to run the Night Scene Show during our open house, the sound of the storm was difficult to hear due to all the other sounds from our active displays and the noise of the trains. So a module board with sixteen relays was added to the control panel that will immediately stop all sounds instigated by our guests. This included an “Iot” Enclosed High-Power (120vac) Relay on Amazon for thirty dollars that is really neat. This was used to stop two amplifiers. Now when the start button is pressed, we have instant quiet.