2
Overview
The Speed Trap uses two optical sensors placed under
the rails and between the ties of your 45mm track. The
sensor shines Infrared (IR) light up and receives the IR
light reflected back. When the train breaks the beams,
the time between the first and second beam is meas-
ured, converted to the scale speed of your choice, and
displayed. Direction of travel and number of laps are
also shown.
Installation
Note: This device is NOT intended for permanent outdoor
installation
, unprotected from the weather. However, the
sensor can easily be inserted under the track for use during
operating sessions, and then removed for proper storage in-
doors.
Insert the sensor under the rails and between the ties, as
shown in the photo. Make sure it is parallel to the ties and
perpendicular to the rails. Note: If readings don’t look realistic,
try moving sensor off center of the rails, while keeping it per-
pendicular to the rails. You may also have to reposition for
different equipment tripping the sensor.
Install a 9V battery by removing the snap-on cover. Carefully
insert a screwdriver or something to pry the cover away from
the base. Attach the battery clip leads and then place the bat-
tery in the battery holder. Replace the cover.
Note: If operating with the cover removed, the red button on
the microcontroller can be used to reset the program, which
will also reset the lap counter.
Speed sensor. The camera sees the IR light (pink)
that we can’t see with the naked eye.
