I need to protect a long tunnel. I want to use two or three light signals to tell operators that there is already a train occupying the tunnel “block.” The interesting thing is that the tunnel area is made up from two separate power blocks.
My understanding is that current sensing detectors must have the entire detection block within the same power block, and therefore I will need an alternative detection, possibly an optical system to do this.
To add to my needs, I want to use as few optical or IR sensors as possible. Is there such a system?
RicZ
Not sure why someone would say current sense detectors all need to be in the sme power block. You cna have 3 sensors, each in a different power block. Or two detection zones in one power block, and one detection zone in another power block. Even the type that actually insert electrically into the path (diode drop types - hate those, they cause a voltage drop) can be split, just not int he dame actual detector - many of those have 4 detection sections per power block, so you'd waste some splitting them up across multipe power blocks, but they still would work. Consider a large layout that is fully detected and signaled, and has dozens of power blocks. It works fine. The transformer type detectors have no electrical connection to the track wiring and it makes no difference what power block a given detector is in.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
RicZ I need to protect a long tunnel. I want to use two or three light signals to tell operators that there is already a train occupying the tunnel “block.” The interesting thing is that the tunnel area is made up from two separate power blocks. My understanding is that current sensing detectors must have the entire detection block within the same power block, and therefore I will need an alternative detection, possibly an optical system to do this.
No, that's not true. You would put a current detector in each block. When either (or both) detector detects, it would cause the signal to change. A problem MIGHT be that the detectors detect ALL of a block, including the part that's not in the tunnel. Perhaps that's an irritation.
Also, they only detect current draw. So any part of your train that doesn't draw current won't be "seen".
Since the signals you want are such a very simple kind, I'd use optical detectors only. If you put the emitter-optical detector path at a very shallow angle across the track (everything is above the track, at train level), you will pick up anything in that path. If you wanna go nuts, you can put in some mirrors to bounce the path back and forth across the track. That might extend it for several feet.
Since the system is inside a tunnel, it can be as ugly as you want. Very convenient.
You might also set it up so that when a train is close to a tunnel end, the signal indication is different than when it's in the middle. Maybe you have three optical detecors, two for the ends and one for the middle. And mirrors.
Ed
Has anyone fad experience with Cicuitron’s BD-1, opticle sensor?
RR_Mel I ran across some Arduino IR detedtors that work pretty slick and they’re cheap too.
I'm with Mel on these detectors, really cheap and really easy to work with. I'm in a similar spot as the OP, hidden tunnel track (mine is where my staging yard leads enter the main at each end of the tunnel, forming an unfortunate overlap in my case). I rigged a sensor at each end, and programmed an arduino to control signals at each end. When a train triggers one sensor, signals placed on the visible portion of my layout just before each end of the tunnel both go red, halting traffic on the visible main before entering the tunnel. When the triggering train hits the second sensor, the signals stay red, but 5 seconds after the train fully clears the sensor, the signal goes to yellow, then 5 seconds later to green. That 10 seconds provides more than enough time for my trains to clear the tunnel and passing track turnout on my small around-the-room. Of course, all the variables are incredibly easy to adjust in the Arduino programming, which was their huge appeal for me.
Great Info... Where is the best place to purchase , also, what are some model No's of cheapo's...
NickyB
Not being a programmer, how did you program your Arduinos? I don’t have the needed access in the tunnel to add a lot of optical sensors, so being able to turn the signals red at each entrance with one and off (green) at the exit(s) is paramount.
I need RTR circuits, already programmed.
I straight copied the codes from the YouTube page of DIY and Digital Railroad's page as a starting point, then tweaked variables as needed.
This was the main video I used, I think: https://youtu.be/Yg6mkOfl6I8
There are a bunch of other videos, too, and most folks have stored their codes online somewhere so you don't have to write the code itself if you don't want to.
I'd recommend trying to write the code yourself, however. None of what I've done so far is hard, and it's good practice to show you what works and what doesn't with Arduino. Tom's Trains and Things on YouTube has a great Arduino series that starts super basic and walks you through some simple programming, and the breadboard work too.