NFC Checkpoint

[OhmMega]

This is an idea I've been working on for a bit.



The concept is using Near Field Communication tags and readers to identify a locomotive or something to allow automated control of either the device for collision avoidance or layout items such as signals. The system also utilizes infrared sensors as part of the package to enable the NFC reader and determine a heading on the track.



Basically it is a way to identify a locomotive or device with an NFC tag and control it with dcc.



Ill be posting more information on this as it matures. I'm currently working on a website to host the information, which should be up soon.



http://www.modelmotive.com

For the source code send me a PM.

 

 

 

Edited July 24, 2016 by OhmMega

[kvp]

Interesting. Wouldn't using two nfc readers be more simple, reliable and allow a better speed detection?

[Melandir]

Interesting. Wouldn't using two nfc readers be more simple, reliable and allow a better speed detection?

 

I was thinking at the same idea

[stevenh]

Once quick point... depending on the cost of NFC readers... you could also multiplex the reader to multiple antennas and read each antenna for 1 second or so (although that's a huge timeslice.)

 

I used the standard RFID readers here and it worked find as long as you got the device as close as possible to the track:

http://modelrail.otenko.com/arduino/tracking-trains-with-an-arduino-and-rfid-implemented

 

Wiring antennas could be done with "transformer wire" or "winding wire" or whatever it's called now.

That way you could have just one reader, having a wire loop antenna in the trackbed or in scenery where you have your IRs.

 

Of course, people have already tried this... seems relays are better than multiplexing:

http://electronics.stackexchange.com/questions/72565/multiplex-125khz-rfid-antenna

Edited May 6, 2015 by stevenh

[OhmMega]

The speed is a known variable via the DCC system. It would only be more simple in respect to number of components (2 readers vs 1 reader & 2 ir detectors). The same number of pins are used in both cases. Programming would be more complex as you would have to cycle through the readers, as only one can read at a time and you generate more class objects which burns up extra memory.

 

The readers are cheap, can be had for less than $2.50 each, and the IR detectors are inexpensive as well at $0.77. And tag stickers again, are inexpensive ~$0.60.

http://www.aliexpress.com/item/MFRC-522-RC522-RFID-RF-IC-card-sensor-module-to-send-S50-Fudan-card-keychain-for/1732292096.html

http://www.aliexpress.com/item/Infrared-barrier-Module-car-obstacle-avoidance-obstacle-avoidance-sensors-Black-Line-Identification-adjustable-distance/1689336014.html

http://www.aliexpress.com/item/Free-shipping-10pcs-Universal-NFC-Smart-Tags-Ultralight-label-for-Samsung-Note3-S4-Nokia-Lumia-920/1385614567.html

 

Heres a preview of my bench test.

 

 

 

[kvp]

If you have more than one hardware serial port, then you can read on more than one reader at a time. Also, it's possible to multiplex them and drive the enable inputs in groups. For example the mega 2560 has 3 free serial ports, which means one enable output and the 3 unused hardware serial ports can be used to read 3 sensors at the same. Then deactivate enable for the current group and activate another 3. This speeds up the reading and you can easily connect lots of readers to a single arduino, just try to avoid activating them too near each other to avoid crosstalk and interferences.

[cteno4]

I did a bunch of work on RFIDs (then called PIT tags) for identifying animals in aquarium exhibits in 1990. You can make your own detection coils very easily and get very different detection areas as you vary the wire gauge, coil diameter and winding numbers. This lets you get the desired detection point for something like a rail application. Just takes some systematic experimentation.

 

Jeff

[Melandir]

The speed is a known variable via the DCC system. It would only be more simple in respect to number of components (2 readers vs 1 reader & 2 ir detectors). The same number of pins are used in both cases. Programming would be more complex as you would have to cycle through the readers, as only one can read at a time and you generate more class objects which burns up extra memory.

 

The readers are cheap, can be had for less than $2.50 each, and the IR detectors are inexpensive as well at $0.77. And tag stickers again, are inexpensive ~$0.60.

http://www.aliexpress.com/item/MFRC-522-RC522-RFID-RF-IC-card-sensor-module-to-send-S50-Fudan-card-keychain-for/1732292096.html

http://www.aliexpress.com/item/Infrared-barrier-Module-car-obstacle-avoidance-obstacle-avoidance-sensors-Black-Line-Identification-adjustable-distance/1689336014.html

http://www.aliexpress.com/item/Free-shipping-10pcs-Universal-NFC-Smart-Tags-Ultralight-label-for-Samsung-Note3-S4-Nokia-Lumia-920/1385614567.html

 

 

Just to better understand

is your test bench H0 or N scale?

[OhmMega]

@Melandir

It is HO scale. I believe there are smaller NFC tags that will fit under some N scale trains.

 

 

If you have more than one hardware serial port, then you can read on more than one reader at a time. Also, it's possible to multiplex them and drive the enable inputs in groups. For example the mega 2560 has 3 free serial ports, which means one enable output and the 3 unused hardware serial ports can be used to read 3 sensors at the same. Then deactivate enable for the current group and activate another 3. This speeds up the reading and you can easily connect lots of readers to a single arduino, just try to avoid activating them too near each other to avoid crosstalk and interferences.

 

That's a clever idea, although I'm still partial to the idea that the readers are inactive until a train approaches. But I can see the benefit of not having to drill and conceal the IR detectors under the track or in scenery. Certainly worth some testing with strategic placement of readers.