Can IR circuits be used to trigger the Atlas 21st Century Signal system?

Junior posted:

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I've even tried to work backwards and figure out what the Atlas controller needs to trigger a signal change (what is it coming from the outer rail that tells the Atlas board to change the signal color?) without any luck.

That's the right question.  What is the input requirement to the "DIN" terminal?  It seems there was a discussion about this in an earlier thread but if you can't find it then so be it.

Obviously, in the absence of further information, you could simply use a relay to connect the outer rail to the DIN terminal whenever your IR circuit is triggered.  Your IR circuit would likely be powered by, say, 5V or 12V DC.  So you could simply use a 5V or 12V relay module which are about $1 on eBay (free shipping from Asia).

But if you're talking block signaling, note that the insulated-rail method is arguably superior for block occupancy detection as opposed to accessory triggering (like to activate crossing gates).  That is, an MTH ITAD or Lionel 153IR only detects an object right in front of it.  The insulated rail detects a train anywhere on the length of the insulated section which could be many feet in length.  Yes, you could cobble together multiple IR emitters and detectors and play with angling the beams to cover a wider field of view so to speak. 

By way of example, consider the crossing-gate application where the train can approach from either direction.  If using the insulated rail method, you simply have the insulated rail section extend from the crossing to several feet on either side of the crossing.  But using an ITAD or 153IR, you must place one on each side of the crossing.  And then fuss with the delay timing feature to keep the gates active for a short consist that as it travels or comes to a stop between the two sensors with neither active.

Hi Guys....

Sorry it took so long to respond. I promised "The Lovely Mrs." I'd swap out an electric range for a gas version (got that done early this AM).

Stan! As usual....you cut right to the crux of the problem. I'm thinking I got lost in the details. Connect a relay to the IR detection circuit to trigger the 18v ground to the Atlas control board (as Homer Simpson would say...D'OH!) .

But I must share.....your discussions threads regarding constructing variations of IR Detection circuits (see https://ogrforum.ogaugerr.com/...87#40989965758239887 ) are off the charts! You provided diagrams, pictures and video on how to not only do this stuff...but to experiment with it as well! And with input from GRJ and RTR12.....who could ask for more! Thanks for helping me see the bigger picture.

Now.....to purchase that Atlas signal 4-pack and components for the IR circuits. WooHoo....time to play! 

Hope someone is still watching this thread!  I have a more general IR sensing question.  For a couple of long, straight sections of hidden track, I would like to sense presence of any rolling stock.  Long range optical sensing with a narrow beam emitter and long range sensitive detector is the tentative idea.  I would use them simply to complete the ground connection for Lionel signal bridges to change them green to red so operators know if there is something blocking a track before their train finds it the hard way.

I spent time on Mouser's site finding a couple of sensors with a 15 meter rated range, and several emitters with 3 to 6 degree narrow beams.  This is a link to my "project" on the Mouser site with the items there to see.  My thought is to place long "walls" between 2 tracks so that a beam on one won't be seen by the detector for the other.

Is this idea feasible?  The track lengths involved are about 30 feet for one pair of mains, 10 feet or so for the other pair.

Thanks for any thoughts, Don

The missing "link": https://www.mouser.com/Project...a4-8b3e-73977d68e71f