Wiring Hookup Notes for the INF-2 Infrared Train Detector and Accessories

The drawing on the last page will illustrate the proper connections for train detection lights, lighted, alternating Cross Bucks, Crossing Bells and lighted, alternating Crossing Gates.

Only a few of the terminals supplied on the INF-2 circuit board are normally used unless several grade crossing accessories are to be connected.

Basic INF-2 Train Detector Hookup

(See the drawing at the end of this document for a pictorial wiring diagram.

Power Input: The two terminals located on the bottom left side of the circuit board are used to supply power to the INF-2. Information written on the underside of the circuit board will also identify these two terminals. Most model train layouts use 14vac as a source of power. The INF-2 train detector uses this same 14vac. However 15 to 20 vdc can also be used. (Polarity when connecting dc power does not matter. Either power input terminal can be used for the dc+ terminal.

Infrared Detector Housing: The infrared signal is transmitted and sensed through an infrared transmitter and receiver led mounted in a separate detector housing and routed through long leads to the main INF-2 detector board. This allows for the INF-2 circuit board to be mounted any where desired away from the infrared transmitter and receiver housing which must be mounted under the train track at the point where train detection will occur.

There are three leads on the opposite end of the detector housing which should be connected to the INF-2 circuit board. Attach the red lead to (S1-R), the white lead to (S1-W) and the blue lead to (S1-B). Often, only one detector housing will be needed. There are situations, however, where other sensor housing(s) might be helpful. They are explained next.

Other Train Detector Situations: The INF-2 contains a turn off delay pot which is used to delay turn off until a train has totally cleared the grade crossing. Some layouts may function better if this pot is bypassed as described below.

Two additional sets of three-terminal inputs are provided on the INF-2 circuit board for certain special applications:

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

2. An extra sensor housing may also be wise for situations where the speed of the train varies greatly as it continually passes a grade crossing. In such cases, the train detector time-delay pot would not properly work to sense when the train has cleared the grade crossing because the time required would vary. Here, a second  sensor housing can be connected to the train detector circuit board and placed under the tracks 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 passes over the last detector housing rather than the timed turn off pot.

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 the same track. In situations such as this, it is best to use two sensor housings, spaced an equal distance from the grade crossing in each direction. Again, set the time delay pot to minimum. This will cause the INF-2 Train Detector to properly turn on accessories before the train reaches the grade crossing in spite of train reversals.

Precise Grade Crossing Control for Train Reversals on a Single Track

The only negative  about train reversals is the fact that accessories  will not turn off immediately after the train has passed the grade crossing but will turn off after the train has passed over the last sensor located further down the track. (This is so because accessories such as crossing gates must have time to properly activate as a train approaches the grade crossing from the opposite direction.)

In cases where the turn off time must be more accurate, two INF-2's should be used. One INF-2 is used to turn on grade crossing accessories for trains entering the grade crossing from each direction. Using this approach, no sensor housings are installed to turn off accessories immediately after the train exits the grade crossing. Instead, the time delay pot should be used to time the train's exit from the grade crossing. (If a sensor housing is installed to determine grade crossing turn off, the turn off detector housing will delay the turn off because it would have to be mounted further down the track to activate accessory turn on as a train approached the grade crossing from the opposite direction.)

Sensor Housing Installation Information: The sensor housing 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 the two tiny holes located in the end of the sensor housing will be clearly visible between a couple of ties once the sensor housing is pushed up under the layout and secured just flush with the underside of the track ties. (See the inset train track drawing at the bottom of the main drawing on  the last page.)

Technical Details: The infrared train detector has been designed to detect the underside of dull black train surfaces up to a distance of 1" from the top of the sensor. This is quite suitable for all trains from "S" scale down through "Z" scale. Trains larger then "S" scale may require a white painted stripe under them to guarantee detection if the underside of the train is further than 1" from the detector housing.

To prevent detection of roof type surfaces in underground storage areas and the like, it is best to use dark mat roofing surfaces with a separation between the roof and detector housing of more than 1". If at least 1" of clearance cannot be secured, contact us for instructions on changing the clearance specifications.

Accessory Connections

Train Detection Lamps and Other Accessories: A filament lamp rated 15vdc, or a led lamp with a protective dropping resistor may be connected between the (SIG) and (B+) terminals on the INF-2 circuit board. (Make certain that the positive lead from a led goes to the B+ terminal.) When a train is detected, the light will activate. As an alternative, a 15vdc relay can be wired to the (SIG) and (B+) terminals of the INF-2 to perform other functions when the train detector senses a train. (Current drain for the INF-2 should be limited to 150ma.)

When an accessory, such as a Cross Buck, Crossing Bell or lighted, movable Crossing Gate is purchased, instructions for wiring the accessory to the INF-2 Train Detector will be supplied. The proper hookup instructions for these accessories are  explained below complete with a picture of various accessory connections at the end of the document.

Installing and Wiring Cross Bucks: Cross Bucks are supplied with three leads, red, white and blue on 12" leads.

Connect the red lead to (CB-R), the white lead to (CB-W) and the blue lead to (CB-B).

When a train is detected, the cross buck will light and begin to alternate like a real cross buck at a grade crossing. Two Cross Bucks can be wired to the same three terminals mentioned above. Adding more Cross Bucks to these same terminals will also work but the Cross Buck lights will begin to dim. (In such  situations, the dropping resistor on the INF-2 circuit board can be dropped somewhat to increase brightness for one or two more Cross Bucks.)

Installing Crossing Bells: The Crossing Bells contain three leads which should be wired to the INF-2 Train Detector. Wire the two (P) terminals on the Crossing Bell to the (B+) and (COM) terminals on the INF-2. The two (P) terminals are not polarity sensitive when connecting dc supply power. Connect the (S) terminal to the (SIG) terminal on the INF-2. If the INF-2 is activated, the crossing Bell will begin to sound as the train passes the grade crossing..

Installing Lighted Crossing Gates: The Crossing Gates are being improved and should be ready for sale again soon. When they are, the following hookup instructions apply:

There are three lights located on the top of the Crossing Gates. Two of the lights alternate in a manner similar to Cross Bucks. The third light remains on while the gate is in the down position to properly represent actual Crossing Gates.

The white lead from the Crossing Gate is wired to the (GA-W) terminal on the INF-2. The red lead is wired to the (GA-R) and the blue lead is wired to the upper (GA-B) terminal. (These leads control the two alternating Crossing Gate lamps.) The black Crossing Gate lead is wired to the lower terminal, also labeled (GA-B) on the INF-2 and the yellow lead is wired to the (GA-Y) terminal. (These two leads control the steady on lamp on the Crossing Gate. All Crossing Gate lamps become operational as the gates begin to drop and remain operational until the Crossing gate returns to the up position.

Stall Motor for Control Gate Operation: Some type of low voltage stall motor is required to move the Crossing Gate(s) up and down in a realistic manner when a train is detected near a grade crossing. We recommend the Tortoise brand of stall motor because of its reliability and provide one properly modified for Crossing Gate use.

Connect the white Tortoise lead to the (TO-W) terminal and the red lead to the (TO-R) terminal on the INF-2.

(members.aol.com/marson07/110htm)