Wiring Notes for Those Planning Installation

of the INF-1 Train Detector

The drawing on the last page will show how to connect the INF-1 Train Detector to cross bucks and most other accessories. In addition, it will show the terminal connections between the sensor cartridge and the INF-1 circuit board. Note that the correct wire colors for the sensor cartridge and the cross bucks are shown on the drawing.

Only a few of the terminals provided on the electronic assembly are normally used. Most accessories are controlled using the same two terminals shown on the lower right hand side of the drawing for the cross buck connections. When these two terminals are activated, they supply up to 15 vdc, converted from the input voltage, to operate cross bucks, indicator lamps and other types of accessories used for train detection purposes. (Maximum current drain, 150ma. Higher output current outputs available if needed.)

Two terminals located on the extreme left side of the circuit board are required to connect a source of power. (14-18 vac, 14-25vdc.) (+ for vdc can go to either terminal.) Three terminals are used to connect the supplied infrared cartridge to the circuit board.

Other Train Detection Situations: Two additional sets of three-terminal sensor cartridge terminals are provided on the circuit card for certain applications.

1. In cases where two or three train tracks parallel the same grade crossing, sensor cartridge(s) can be installed and wired to the extra sensor cartridge terminals to detect trains passing the grade crossing on those other tracks.

2. An extra sensor cartridge may also be wise for situations where the speed of the train varies greatly as it continally passes a grade crossing. In such cases, the train detector time-delay pot would not properly work to tell when the train has cleared the grade crossing because the time required would vary. Here, a second sensor cartridge can be connected to the train detector circuit board and placed under the track immediately after the grade crossing. The time delay pot is now adjusted to minimum so that the accessories will turn off after the train has passed over the last detector cartridge rather than the timed pot turn off.

3. The train detector works properly for trains going in one direction on any given track but does not work well for trains reversing directions past the grade crossing on that same track. In situations such as this, it is best to use two sensor cartridges, spaced an equal distance from the grade crossing in each direction. Again, set the time delay pot to minimum, as mentioned in the last paragraph. This will cause the INF-1 Train Detector to properly turn on accessories before the train reaches the grade crossing in spite of train reversals. The only negative is the fact that accessories will not turn off immediately after the train has past the grade crossing but will turn off after the train has passed over the last sensor located slightly further down the track.

Sensor Cartridge Installation Information: The sensor cartridge is mounted by drilling a 3/8" hole directly under the train track ahead of the grade crossing enough to allow some distance from an approaching train and the crossing itself. The 3/8" hole must be drilled so that the two tiny holes located in the end of the cartridge will be clearly visable between a couple of ties once the sensor cartridge is pushed up under the layout and secured just flush with the underside of the track ties. (Some hobbyists like to lay tracks down after the sensors have been mounted in place to create perfect placement.)

Technical Details

The infrared train detector has been designed to detect the underside of dull black train surfaces up to a distace of .8" from the top of the sensor. This is quite suitable for all trains from "S" scale down through "Z' scale. Trains larger than "S" scale may require a white painted stripe under them to guarantee detection.

To prevent detection of roof surfaces in underground storage areas, it is best to use dark mat roof surfaces with a separation between the roof and detector cartridge of at least 1" or more.

See installation drawing below.