Model Railroad Electronics - 4x Channel Block Occupancy Detector (Current Sense)

In this listing, I have for sale ahand-made Four Channel Current Sensing Block Occupancy Detector. Ihave designed, engineered, crafted, modified, assembled, tested andpackaged this product by hand in my workshop. I originally designedthe first batch to express to model railroaders how the prototypesignaling system works. As soon as I had finished the first batch, Ihad modelers demanding that I go to production and develop these fortheir layouts.

HOW DOES IT WORK?
Each channel senses the electricalcurrent going from one rail, to the other when something enters ablock of track that conducts even the slightest amount of currentthrough it. Something as heavy as a locomotive motor to something aslight as a resistive axle with 39,000 ohms resistance. In fact, evena damp finger should trigger the sensor if you\'re doing it correctly.It does not use a transformer, so therefore it does not requirewinding your own coils. And most importantly IT\'S NOT OPTICAL! So nocluttered layout with optic emitters and receivers, potholes and hugegaps between ties, funny looking not-to-scale trees to try and hidethe optics... Modern prototypical railroads use a system very similarto detect and predict train movement within a block of track forhighway grade crossings, wayside signals, drawbridges, remotecontrolled turnouts and many more functions. The chief difference isthat their locomotives are either powered by a third rail or catenarywire, or by their own power plant, whereas most model railroads use acurrent provided in the rails to power the train. This makes it easyto detect the locomotives. But it does make detecting the cars alittle more difficult only because your wheels are either isolatedwith an insulated bearing or they have non-conductive axles.Depending on how long or short your blocks are, you just need atleast one of those resistive axles or locomotives in the block totrigger the sensor. If your shortest block is 18 ft and your largesttrain is 15 ft long, then you can get by with one resistive axle onthe rear car. On the other hand if you are using my detectors tooperate realistic grade crossing signals and want the signals toproperly trigger and release, you\'ll want a resistive axle on the endof each car.

For HO Scale, I can recommend[link removed by ]to provide you with quality wheels for all your model needs. Istrongly recommend the 39k-ohm sets.

AND WHAT DOES IT DO, EXACTLY?
For each channel, the detector providesa Logic High and Low status for microcontrollers such as Arduino,Raspbery Pi and so on. It also provides an ON/OFF connection for boththe Clear and Occupied Statuses. The connection switches the Negativelead, leaving the positive as a common lead for whatever hardware youwish to connect to it. You can use it on Lamps or LEDs, Relays,servos, sound players and so on. For the simplest of applications,you can connect a Red LED to the Occupied lead, a Green LED to theClear lead and your DC Positive to the Common Anodes of the LEDs. Ifthe block is clear, the green light will illuminate. But if the blockbecomes occupied, then the red light will illuminate.

It is strongly recommended againstusing the Digital outputs to drive LEDs in signals, or any kind ofrelay or motor.

But the simplest answer to thisquestion is that it will give you an electrical status as to whethera block of track is occupied or clear. What you do with thatinformation is up to you because the number of applications for thisdevice are as countless as the stars!

WHAT SCALE MODELS WILL THIS WORK ON?
So far, it\'s worked on Z, N, HO, S O, Gand even 1-1/2” scale without any problem. It supports DC, DigitalCab Control, and AC-powered systems.

(On systems like G and larger, thesolution was to simply provide a power source such as a pair of AAbatteries across the rails to show that there was something shuntingthe rails when occupied.)

WHAT DO I NEED TO MAKE IT WORK?
You will need a section of track,called a “Block” which shall be electrically isolated from otherblocks of track. You\'ll need something on your equipment that drawspower from the tracks, as explained earlier.

You will also need an independent powersupply that is not connected to your track power. A simple walladapter will do. For Power options, please check out my powerdistribution board listings here:

HOW COMPLICATED IS IT TO CONNECT?
It really is just a matter ofconnecting the Track power to the detector, then the detector to yourtrack. Provide your Detector with adequate “ISOLATED” DC power tothe Aux Power In and you\'re done with the detector portion of thisproduct. Now each time a train runs through the block of track,anything that conducts electricity will trigger the sensor and letyou know the block is occupied.

WHAT APPLICATIONS IS THIS PRODUCT GOODFOR?
Literally anything that requires thedevice to identify that a block of track is occupied and/or clear.Some of the most simple applications are for things such as:

• Grade Crossing Signals

• Wayside (CTC / ABS) Signals

• Station Stops

• Automatic Turnout Controllers

• Drawbridge Operation

• Dispatcher Control Operations

It\'s simply a matter of applying thelogic, where if the block is occupied or clear and you need anelectrical signal to tell you so, this is the device you need.

WHAT DO I DO WITH THE DEVICE ON MYLAYOUT?
Mount it using the 4 1/8-inch holes onthe corners and stand-offs so that the circuitry is not makingcontact with whatever you\'re fastening it to. You can purchase simplemounting hardware for this online at your favorite hardware supplier.If you have multiples of these cards, you can stack them to savespace, using a 1-inch riser between each of them.

They do not have to be stacked up inone central location unless that\'s your desire. There\'s nothingwrong with doing it that way if that\'s what you choose. But Irecommend that you wire your track using a common bus and then theisolated rail(s) pass through the detector, which may require you tospread out your detectors along your layout. Take care to not runyour wires more than 35 to 50 feet from the detector. If you have torun more than 50 feet of wire between your detector and the track orpower supply, consider dividing up your power and track controls tomultiple locations.