Need help on selecting simple current sensing detectors for signal system

[Southwest Chief]

I'm looking to add current sensing detection on my fairly small HO scale layout for my signal system.  To control the signal indications I'm using Logic Rail Block Animators, the infrared versions.

My set up is pretty simple.  For track power I use a Digitrax Zephyr.  I already have track feeders and bus wiring installed on the layout, but it shouldn't be tough to add blocks for signaling.  Here is a track diagram showing all the signals on my layout:

Although I have the infrared detectors that came with my Block Animators, I prefer to have a current sensing setup.  And being such a small layout, resistor wheelsets for my rolling stock is not that big of an issue.

The problem I'm finding while doing research online is that most current sensing detectors/systems seem to have way more features then I need.  All I need is a stand alone sensor for each block that I can act as triggers for my signal boards (Block Animator).

Perhaps the NCE BD20 might be what I need?

Although I'm having a little difficulty finding online how tos or tips using the BD20s for a super simple set up like I have.  Or even a clear set of instructions on how to wire them.

I would greatly appreciate any tips or recommendations for adding current sensing to my layout.

[rrinker]

 Most of the various detectors, including the BD20, are open collector outputs. It does not appear that the Logic Rail Signal Animator uses an open collector input. I would contact Logic Rail - they can tell you if the BD20 can be hooked up in place of th photocell or IR transistor, or if you need an interface circuit.

 A sneaky way might be to use the BD20 to drive the IR emitter (just like an LED - the diagram for an LED is given in the BD20 manual) and just put the LED and IR phototransistor together with some heat shrink around the pair to hold them together facing each other and to keep out stray light.

                  --Randy

 

[gregc]

if you willing to build your own circuits, you could probably save some $$ by building Rob Paisley's Dual Detector Circuit.   Looks like you'll need a few detectors as well as additional logic to combine detectors to control the three color signals.   The pulse transformer are < $2 a piece and the other components are fairly cheap.

 

[Renegade1c]

I use rr-circuits BOD-8's for my block detection. They can be powered by 5volts. I would tie the grounds of the block animator and the bod 8 together and then connect the output pins to the photocell inputs of the block animator. The BOD-8 is capable of providing block detection for 8 blocks. They also make a significant gle block detector but I can't remember it'S part number. Also in addition to the BOD you would need the current coils. All can be found on Tony'S train exchange or direct from RRcirkits.

[Southwest Chief]

Thanks for the tips.

The Block Animator can use current sensors in place of the IR sensors:

https://www.logicrailtech.com/ba_appnote_current_sensing_detectors.pdf

[DigitalGriffin]

Option A:
Do you have your circuit breakers installed per block?

If you don't have your circuit breakers, you could use DCC Specialties PSX which has two terminal outputs that tell you when the block is occupied.

Two birds 1 stone. 

Here is a manual:
http://www.tonystrains.com/download/PSX-1-2-3-4_install_man_RevM_for_website.pdf

The only drawback is they are single leg breakers.

Option B:

google "model railroad circuits" or "model train circuits"  See what pops up.  There are about 5 or 6 dedicated pages out there for the DIY scratch builders.

[demircik]

I do not have much knowledge about it but i want to say that if you are willing to build your own circuits you must build Rob Paisley's Dual Detector Circuit.

From the description given by you it is lloking that you need a few detectors as well as additional logic to combine detectors to control the three color signals.   The pulse transformer and the other components are fairly cheap.