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> Awesome looking crossing. I like the small size of the motors. What do you
> use to control this? I was in a hobby store last week looking at DCC stuff
> and they had crossing sensors for this sort of thing.
That's what a RCX with a extra light sensor is for (or homemade light sensors).
Either option beats the pants off how I did my first automatic crossing system-
it was a electrical kludge (and I still can't think of a better way to do it- in
case you are wondering, it was a twin T detector, firing a (homemade) momentary
contact relay, controlling a 555 timer circuit that controlled how long the gate
went down for, and it then went back up...)
Programming the logic inside a mindstorms is FAR easier than doing it with relay
logic (mechanical relay logic). It makes me wish for TTL for my current job :)
(1)
> Also, what happens with the gate is down? Do you have to manually stop the
> motor so it doesn't burn out? I've been thinking about how to fit a
> microswitch in to a 1x2 brick with a 1x2 tile on top as the sensor for when
> one of these type of gate is up or down. Has anyone done any work with
> this??
I'm assuming here that the crossing uses the normal style of micromotor driving
crossing gates via a rubber band- you don't need to be fancy, just use the dwell
time. Drive the gates down slightly longer than the reverse time, so they come
to a complete stop against the lower stops. Simple, and it works. Be warned,
that doing so with the micro motors direct coupled to the crossing arms is not
recommended, since it tends to lock the micromotor solid, requiring human
assistance to get it to turn again.
James Powell
(1) In case you are wondering, I work with a analog computer for my day job-
Pnumatic air controls for a ship. They are a bit...old.
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