I'll put it on my "roundtuit" list - I will at some point need at least one because one of the branches I plan to have on my layout had a station signal near the beginning using a semaphore. Not a train order signal, the branch didn't operate by TT&TO.
No point in latching it - and you can even kill power to the servo like I am with my turnout controller. With a model semaphore, at least anything smaller than G scale, you'd break the signal before the servo would turn if you tried to pull it up by hand even with the servo powered off. Ditto for an upper quadrant in the up position - it's not going to fall down on its own even if the servo is powered off.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
What I want to see is the detail design and programming of an Arduino (or whatever) that drives a servo proportionally including the bounce and then prototypically raises them when done.
Is there any point in latching them at the bottom, vs. just holding power against the bottoming stop or spring while the gates are down? Hey wait, won't a servo hold position on its own?
I control 2 crossing gates (one on each side of the crossing) with a Tortoise. The Tortoise is controlled by an Arduino that reads the occupation states from Bruce Chubb Optimized Detectors. The track is gapped right at the crossing with a detector on both sides of the crossing. The Arduino code not only monitors the detector status but uses logic to determine the direction of the train relative to which detector is activated first.
For years I’ve used a Grade Crossing Pro from Logic Rail Technologies.
https://www.logicrailtech.com/gcp.htm
It has worked extremely well for me. Like Mister B. I used linkage to control not just two gates but two two track crossings or four crossing gates with one Tortoise.
https://drive.google.com/file/d/0B7gZp9MPvrm3M003clFiYVlscHc/view?usp=sharing
https://drive.google.com/file/d/0B7gZp9MPvrm3OEU3X1NIOElnMTg/view?usp=sharing
Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
I have one pair of crossing gates, crossing two parallel tracks at that point. I drive both gates with a single Tortoise, using remote linkages also from Circuitron. I use Rob Paisley's detection and control circuit which drives both the gates and the flashers. My gates are from NJ International and my crossbuck flashers are from Oregon Rail Supply.
The detection circuit runs on 12 volts DC. It provides both the alternatingly flasher signals and the drive voltage that runs the Tortoise. The voltage seems to give me a good speed.
The same circuit also provides an output for a warning bell module if you have one. I don't, but someone brought over a REAL crossing bell. It runs on 12 volts, so we hooked it up to the Paisley circuit and ran a train. It was really cool, and very loud. I didn't know how much current it was drawing, so I disconnected it after that, but the circuit did that job, too.
It takes an iron man to play with a toy iron horse.
Haven't gotten that far yet, but I will almost certainly use servos. With a servo, it is possible to program in the action of the prototype, instead of the one smooth motion of a Tortoise. You can find videos demonstrationg this with a servo controller semaphore signal, having the 'bounce' of a real one when it drops.
One thing to consider here is that you can use a 'dashpot' with variable resistance at different points in its stroke to model the action of a real crossing gate, rather than just motor it up and down with something like a Tortoise which I think is the best regular solution if you can afford it.
Even a solenoid and spring can be used to power a gate if you have the variable resistance to motion set up. It goes down all the way, putting tension on the spring to power the actual gate movement, which is then regulated by the resistance. That's probably cheaper than something with a motor, and it lets a simple return spring (with its own 'dashpot' resistance) govern the raise after the train clears the crossing circuit.
There were drawings in an old model-railroading book (it was old and dog-eared when I came across it in the 1960s, if you want to know how old) that showed how to use a linkage and 'cam' cut from a piece of wood to provide the variable resistance to motion -- you had a spring-loaded roller follower that had more or less resistance running up or down the profile.
What type of actuator do y'all use to raise and lower a crossing gate? I have several Bachmann gates that I am wanting to tie into my flashing crossing lights.