>How can I set up a trolley in my layout to stop at the end of the line,
>reverse, then stop at the other end and return, all automatically?
Use a momentum throttle. Set the throttle up so that a pot holds the
speed level on the speed cap. Put a current sense detector (like Chubb
or TracTronics) on the end section of track at each end. Hook the
detector outputs to the speed cap through a resistor. Disable each
detector output with one pole of the reversing relay. Hook up the
reversing relay as a latching relay, and drive it off a voltage sensor
(op amp or comparator) set for output at voltage lower than .3 volts
or so. Sounds complicated, but all this is pretty easy.
When the trolley hits the section with the detector, the detector starts
to pull down the speed cap, and the trolley slows to a stop. When the
throttle output goes below about .3 volts, the voltage sensor kicks the
reversing relay and reverses the throttle. This also disconnects this
detector from the speed cap, and connects the other one, which is not
currently detecting. The trolley gradually speeds up to the pot setting.
Same thing at the other end.
Rich Weyand | _______ ___,---. ---+_______:_ |Rich Weyand
Weyand Associates| |_N_&_W_| |_N_&_W_| |__|________|_ |TracTronics
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