WR&N IV Animation: Stoplights

It's a tough call to decide if working stoplights constitute "animation." But I've always maintained anything that changes its state is animated, not merely anything that moves. This five-way intersection on the WR&N IV had a full compliment of proper traffic signals, including left-turn arrows and pedestrian lights. I used the very smallest LEDs available at the time, which were pretty close to the right size, but disappointingly dim.

At the time—twenty years ago—the technology didn't exist for ultra-small plugs and sockets, otherwise I'd have made the signals removable. As it was, each signal had either three or four LEDs, and a few had six, counting the walk/don't walk indicators. The entire intersection was built on a base of PC board; after the signals were assembled and attached, I applied a road surface to the PC board, then installed everything on the layout.

Complicating the assembly were the two police cars, each having functional ski racks and headlights, and the car accident in the middle, where the garbage truck had working four-way flashers. All of the vehicles were removable; the police cars had self-contained flasher circuits, so all they needed was power, which was supplied by a pair of pins that slid into tubes mounted on the PC board.

The signals were controlled to run an entire sequence for the five roads, including a period for left turns. The complexity was such that I found it easier to build a mechanical controller, which worked like a player-piano: a drum with raised strips actuated microswitches with rollers.

Return | Home

Copyright © 2017-2018 by David K. Smith. All Rights Reserved.