Timer Circuit for 154 Question for Stan2004

It's triggered by the 153IR MODULE MTH sells! look below at right side of schematic you'll see it!

LIONEL 153IR INFRARED TRACK CONTROLLER O GAUGE operating Fastrack 6-14111 NEW | eBay

Alan

I'm sure he'll answer, but to trigger any circuit or accessory that depends upon the presence of a train on a track, you can use the insulated rail method, explained in this forum many times. In this case, one side of the accessory supply gets bonded to the track outside rail supply and one wire to the accessory gets connected to the insulated rail. The other power wire goes to the accessory. The wheels bridge the rails and complete the circuit.  There are many ways to provide the AC supply required, either from a separate transformer, phased with the main transformer, or a suitable output from the track supply transformer that shares a return with the track.

Arthor i agree with you, but he asked what triggers crossing gate and in the schematic stan provide the 153IR is what senses the engine and cars coming,

@Mike1234 posted:

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My question is how do you trigger the circuit.  It looks like the trigger is a 3 to 24 volt input.  Where can this come from?

I believe by 3-24V input you're referring to the digital timer module shown later in the thread; the 153IR example mentioned above is not used in this case.  The eBay or Amazon listings show 2 trigger input screw-terminals to the module stating 3-24V as shown below.  Yet, in my wiring photo, these 2 trigger inputs are not connected.

So as it turns out, this timer module can be programmed to not require a trigger.  That is, you simply apply DC power to the module and away it goes...clicking on/off and alternating the lamps as long as power is applied.  This module and essentially most of this ilk have a wide variety of "modes" of operation.  Some modes require a trigger, others don't.  For example, you can give it a trigger and it will click on and off exactly 123 times then stop...until the next trigger.  And so on.

If using the insulated rail method, note that the configuration shown is simply powered by 2 wires AC coming in on the left.  So it could be wired like any other 2-wire AC accessory to operate when the insulated rail is occupied.  Of course it could also be triggered by the 153IR since the 153IR does not internally have alternating flasher capability.

Thanks Stan and everyone else.

I want to use the timer module to cycle and  E unit at the ends of a back and forth track.  I found the data sheet here

https://www.mpja.com/download/35238mpdata.pdf

I think I can make it work by using an IR proximity sensor to detect the train at the end of track and using P2 in the data sheet iff a continuous voltage on the trigger input will be seen as a second trigger after the timer cycles.  In P2 mode the module runs it's cycle when triggered and then waits for the next trigger.  The IR proximity sensor will put out a continuous voltage to the trigger while the train is on top of the sensors.  The question is  when the module completes it's cycle, will it see the still applied voltage to the trigger input as a "new" trigger or still the initial trigger.

I ordered a couple of the timer modules to play with.   I've used the IR sensors to control relays to change signal aspects so I know that part works.

Mike

@Mike1234 posted:

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I think I can make it work by using an IR proximity sensor to detect the train at the end of track and using P2 in the data sheet iff a continuous voltage on the trigger input will be seen as a second trigger after the timer cycles.  In P2 mode the module runs it's cycle when triggered and then waits for the next trigger.  The IR proximity sensor will put out a continuous voltage to the trigger while the train is on top of the sensors.  The question is  when the module completes it's cycle, will it see the still applied voltage to the trigger input as a "new" trigger or still the initial trigger....

For the timer modules I've seen, the trigger must be a transition from OFF to ON.  If the trigger signal is held ON, it will NOT retrigger an additional cycle when the first cycle completes.  But it's a your-mileage-may-vary.

For example, I notice in the MPJA datasheet that you linked to, there is only a mode P2.  I have over time received different versions of the identical looking module.  And the number of modes has increased.

For example, in the version labeled JZ-801 there are two versions of mode P2, namely P2.1 and P2.2.  One is "re-triggerable" so a new trigger can restart the timing in the middle of an active cycle...the other is "non-re-triggerable" meaning additional triggers are ignored in the middle of an active cycle.

All the timing modes are complicated enough that I drew out timing diagrams like above to form a cheat-sheet.  Notice for example that in my JZ-801 cheat sheet it even shows a mode P1.4 which the mpja datasheet does not have.  Not that P1.4 would apply to your specific situation.

You might consider one of the mode 3 scenarios.  In general mode 3 is to generate multiple pulses in response to one trigger.  So if I understand your application, you want 2 relay pulses in response to 1 trigger when the train nears each end of the track.  Each relay pulse would momentarily remove track power to advance a reversing-unit from Fwd-Neutral-Rev at one end...or Rev-Neutral=Fwd at the other end.

BTW, since it appears you know your way around circuits, the 2-terminal 3-24V trigger input you asked about is simply a 2K resistor feeding an optocoupler.  The datasheet does not tell you the trigger current requirement.  So if your IR detector output is, say, 5V then it must supply about (5V-1V)/2K = 2 mA of trigger current since the forward voltage of an optocoupler is about 1V.  I can imagine scenarios where you want to "debounce" the occupancy detector to avoid falsely re-triggering the timer.  For example, there might be an advantage to using a single timer module triggered by either of the end-of-track occupancy sensors.