how to use a infra red detector with single pole relay to cut track power

[GeorgeG]

I purchased some of the new IR detectors from MR Matix (mrmatix.com) which come with a single pole relay actuated when the train is detected. Is there any way to use the relay to cut the power to an isolated storage track segment, and then have a manual override switch to repower the siding to move the train again.

Moder Railroader had a piece in May,2007(p64) but this used a double pole relay. I just can't "think" electronics very well, but can follow simple wiring diagrams. Any help would be really appreciated.

GeorgeG.

Ho layout run on DCC(NCE)

[rrinker]

 One of two things. Simplest is to put insualted joiners in ONE rail of the section you want to cut power to. Feed that rail via the realy on your detector. Basically, all wires going to the now insulated section of track, cut. Connect one side to one relay terminal, connect the other side of the cut to the other relay pole. The detector should have come with a diagram which shows which two terminals ont he realy connect together then no train is detected, I would assume you want to use those, that way the track will have power when no train is there, and when it detects a train, the power is cut. It's fine to cut just one side, you don't NEED the double pole relay which cuts power to both rails.

Method two, use the single pole relay to drive a double pole relay and otherwise follow the article. You need a double pole relay and a power source (cheap DC wall wart should be fine). Power to double pole relay coil is switched by the single pole relay on your detector. Track wiring goes to the double pole relay - hookup would be exactly like in the article.

                                                     --Randy

 

[Seamonster]

Check the instructions which came with the detector to see what kind of relay the board has. It could be a single open contact which closes when a train is detected. This would be used to turn on a light or other indicator and wouldn't work for you. Or it could be a changeover contact where one common point is connected to an output when the detector is quiescent then when the detector detects a train, the common contact moves and connects to the other output. A double pole relay is just two separate sets of contacts in the same relay and these contacts could be either of the two configurations I've described. What you need is a changeover contact, known as a double-throw contact. Unless you want to also activate something else, you need only a single contact to stop your train. This type of contact would be called a single pole double throw contact (SPDT). Lacking the information on the manufacturer's instructions, how many output connections does it have? If it has only two then it's a normally open contact and you would have to use it to power an external relay. If it has three, then measure the combinations in pairs, One of the pairs should show continuity. That's the normally closed contacts. Put your hand over the detector and that pair should show open. Now with the detector still blocked, measure from each of the previous outputs to the third output. One of them should show continuity. That's the normally open contacts. The output which is common to both other outputs is the common one. Route the power for one rail from the throttle to the common contact and from the normally closed contact to the rail. Now when a train blocks the detector it should remove power to the track and stop the train. If you don't have a meter to measure continuity with, simply attach one lead of a 12 volt lamp to one terminal of a 9 volt battery and attach a clip lead or wire to the other battery terminal. Use the clip lead and the free lamp lead as probes. When there's continuity between them the lamp will light up. Hope this helps you. If you need to add an external relay, PM me and I'll show you how. Oh, for manual override, simply connect an on-off toggle switch across the output of the detector where you have the two track wires connected. Close the switch for override, open it for automatic stopping.

[boatman909]

 If you look at the wiring diagram and instructions for the MrMatrix MRD1 here, it does everything you want.  It even tells you what relay to purchase from RadioShack.

 

John
__________________________

Steaming into the future

[larak]

GeorgeG

Is there any way to use the relay to cut the power to an isolated storage track segment, and then have a manual override switch to repower the siding to move the train again.

 

Sure, use the relay to cut power to one rail and hook a single pole momentary normally open switch across the contacts.

Press button and track is powered. Once the train leaves you can let go of the button.

Simple.

[GeorgeG]

I want to thank everyone for their help. I got several solutions. I also asked MRMatix the same question. The owner produced a complete circuit diagram and parts list for me, which one of you also spotted. I really appreciate your help.

George G.