The Car shows the distance a train travels on a 5 digit LCD display. The distance is indicated down to 1 of 100th of a mile (about the length of a 50 foot car) with an accuracy of approximately plus 2 percent using a standard 33 inch freight car wheel.
Simply stated, the Odometer Car counts the number of revolutions of one of the axles, divides it by six and displays the result on the counter module.
Odometer Parts List
COUNTER MODULE – Radio Shack part number 277-302 (see notes)
OM1 – Infrared Emitter/Detector module
TIL 139 (see notes)
IC1a, IC1b – 1/2 of LM393 Dual Comparator
IC2 – MC4017B Decade Counter/Divider
R1 – 470 ohm 1/4-watt
R2, R5 – 470K ohm 1/4-watt
R3, R4, R6, R7 – 22K ohm 1/4-watt
C1, C2 – 0.1uF
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