Problem Solved - Help wiring the O Scale Pennsy Signal Bridge and ITAD

Ron-

It sounds like the sensor is positioned in a way where another light source might be causing interference. Try repositioning the sensor and adjusting the "range" to see if it improves reliability. The "delay" dial I believe is used to adjust the time delay between when the contacts change back to the default state.

Another option to consider is completely eliminating the ITAD and using an insulated track block with a relay. The insulated block performs the same function as the photocell, but without the need for sensitivity adjustments.

-John

John,

You hit the nail on the head.  The problem is you are too right.  I moved the signal bridge from the work bench were there is lots of incandescent and florescent light to the spot on the layout were there is a lower amount of incandescent light only.

The first issue... I had to re-wire the ITAD the proper way by reversing the NO and NC.  Then the system would only work in the dark.  I do not have a lot of light on my layout.  It's hard to understand why this thing is so light sensitive.

Here is a video.

The ITAD "shoots" an infrared beam out one window and looks for a reflection (off the passing train) in the other window.  The RANGE control adjusts how much reflected infrared energy is needed to trip the sensor.  So you might try adjusting the RANGE control. 

As you discovered even though invisible to the eye, there's a lot of infrared energy particularly from incandescent bulbs.  Depending on your layout location you might try putting a shade or window awning (so to speak) over the sensor window on the ITAD.  This might block any extraneous infrared energy from your ceiling lights.

Ron,

I have 2 such Pennsy signal bridges.  The directions were less than clear.  I ended up activating them using insulated rails and relays (Z-Stuff DZ-1008a).  Dave Hikel was very generous and provided me with a wiring diagram that I will post below.  The diagram shows a different signal, but it does work with each signal head of 30-11030.

You might give this a try.

Best,

George

George,

Thanks for the feedback.  I just may use that method in the long run.  But I wanted to lick this problem.

LET THERE BE LIGHT... Problem Solved.

About a month ago my Wife matted and framed a picture.  She gave me some scrap silver mat board because she knows how I like to re-purpose things for the layout.

Initially I thought, "What the heck will I do with this?"  But I kept it anyway.  Today I used that silver mat board to make a "sun shade" for the ITAD.

This is not the final installation... just a mock up to prove it works.  Video and pics below.  The range is on the very lowest setting as is the delay.

Thanks all for the help!

Ron

We use insulated tracks and a simple relay to sense presence.  If you want a larger delay, just increase the size of the capacitor.  If you go much bigger on the cap, I'd stick a 27 ohm resistor in as well, just to limit the inrush current.

These are trivial to build, and I just bolt them under the table next to the signal.

Yes, it's on a scrap of plywood, and the relay and cap are hot-glued down.  The terminal strip makes it easy to connect these up when use them.  Not fancy, but it doesn't need to be, just needs to reliably trigger the relay when a train comes by.  The relays are scrap from old PLC control boards, so the cost of this module is minimal.

I thought the cap in this circuit is for anti-chatter to provide "just enough" energy storage to ride out the single-diode rectified AC and maybe brief loss of wheel contact.  Seems to me if you increase the cap value to one that holds the relay for 5-10 sec (or whatever), the cap charges up to 25V or so and stay there as long as the train is over the sensor.  I'd think most 12V relays would get hot under the collar.

I've left these energized for several hours on the bench, and I can't detect any temperature rise in the relays, so I don't worry too much about the temperature rise.  Some of these have been working for several years with no sign of impending failure.  If you use different relays, you can just add the appropriate sized resistor to drop the voltage to the relay.  It's quite frequent that a train will be stopped for extended periods of time on one of the signal tracks, no issues have been detected so far.  You're probably right that some relays might object to the extended higher voltage.