Traffic Signal Controller

The Traffic Signal Controller Card

The Traffic Signal Controller card is designed to run autonomously by cycling through the signal aspects of a 4-way highway intersection on a model or miniature layout. Parallel traffic will share the same aspect while cross traffic will have the opposite.
The card features a power indicator lamp, clock lamp (you can see how fast the clock is operating) and a clock trimmer so you may adjust the clock speed to your desire.

Signal phases

The card cycles through 10 phases at equal speeds. Phases 1-3 are identical, as are phases 6-8. This means if you set your cycles for 3 seconds each, you will have a green light for 9 seconds, followed by a yellow for 3 seconds and then red in both directions for 3 seconds. You will be able to adjust your clock speed by adjusting the position of the trimmer resistor on the edge of the board. The range is between 1/5 of a second (200ms) and 7.4 seconds per cycle.
While the card is designed to operate two opposing traffic signals or more, it may also operate a single traffic light for demonstration as well, such as a wall-mounted display.
The operation of the card requires an input voltage of 6 to 15 volts DC. The output has a common Positive or common Cathode if you are using LEDs, with the negative supply switched using power transistors capable of up to 600mA per channel. This should allow for as many signal heads as you can fit onto your layout. Figuratively though, if you are using LEDs at 20mA each, you should be able to put as many as 30 LEDs on each channel.

Diagram of how to connect the Card to your signals

Ideal connection to the card means you would be sharing a common positive with the board and the signals. If however you are using a lower voltage, say for instance 1.5 volts for your signals, then you would need to use a separate power supply for your signals than the one operating the card. This can be easily done by isolating the positive leads but combining the negative leads.

Diagram of how to connect the Card to your signals using an isolated power source