IR Detectors

Peter, I have spanned about 18" of distance with IR detectors, however, I have not used the Lionel or MTH ones. I have quite a few from Azatrax. They have worked well for me and are easy to hide in adjacent building walls or even tree stumps, dwarf signals, bungalows. I will post a link, if I am allowed. If it gets taken down, I will send to your email.

https://www.azatrax.com/ir-model-train-detector.html

I use the MRD1-NV because I don't need variable timing, however, it is a nice option. IR detectors and emitters are included with the board. Good Luck!

Mike

I have no experience with Azatrack detectors, but those distances are pushing your luck with IR detection IMO. Different colored rolling stock, different lighting conditions, different shaped cars all create too many variables.

I have been using ultrasonic HC-SR04 detection with very good success on my layout for the last couple of years. It is very precisely adjustable as to detection distance span, up to about 1 meter. And it does not care about color or shape of object. It even works on unibody tank cars where IR fails miserably in my experience.

The subject was covered here in great detail by Stan2004 and gunrunnerjohn as well as others. Just search HC-SR04.

Rod

@Rod Stewart posted:

I have no experience with Azatrack detectors, but those distances are pushing your luck with IR detection IMO. Different colored rolling stock, different lighting conditions, different shaped cars all create too many variables

Rod

I use the Azatrax D2T - DS.  This uses two pairs of IR sensors. One sends, the other receives. The same way your TV remote works.

It essentially casts a beam across the track, when the train car breaks the beam the accessory is activated. Car colors and shapes do not matter.

The only requirement is for the detectors to point across the track at an angle so the beam can't go between the cars.

For about half the cost of 1 Lionel or Mth ir detector it detects 2 trains across 2 or more tracks easily from any direction. No added relays etc. There is enough wire to allow triggering from about 3' before the train reaches the crossing on either side.

The beam easily reaches 18" , and will go further as long as the detectors are aimed , which I've found isn't difficult as they operate even when not exactly in perfect alignment.

I've had this operating my mth crossing with sound for a few years now, with zero issues.

Another vote for Azatrax. Great Products with well written instructions. Work very prototypically. Come on well before the train gets there. Goes off just after it passes. No matter which direction your traveling. I ended up putting mine in the roadbed. Easily hidden if that matters.

I have not used any IR detectors but would agree a photo interrupter type would be the better choice here. Unlikely a photo reflective type would be reliable at that range.

Pete

https://photos.app.goo.gl/oyxeMNoPrA3Pye4L9

Hey Pete, I used four Z Stuff detectors for my gates. Dennis Z Gave me a wiring diagram to do crossing gates. All are working fine. I also used a bell from Z stuff. Dennis wiring diagram works fine. Bill

How about an ultrasonic detector?  I even have nice cabinets for them.

These boards go inside the cabinet.

These have range adjustments and sensitivity adjustments.

Very nice John.

Here's another vote for the Azatrax detectors.  They work great.   • Across-track sensing can cover a longer stretch of track when the IR LED and its receiver are placed at an angle across the track. The shallower the angle, the longer the length of covered track. The IR LED can be as far as 18 inches (45cm) from its receiver when used in across-track configuration.   https://www.azatrax.com/ir-model-train-detector.html

The ultrasonic detectors John mentioned are working great on my layout. Adjustable for picking just the closes track or multiple tracks. Can adjust delay after train has cleared.