Tracking trains with an Arduino and RFID

17Feb/1010

Tracking trains with an Arduino and RFID

So, you're now controlling your trains with your Wii Nunchuck and an Arduino... What if you get tired and want them to run by themselves? This next project will help you with one piece of the puzzle, as long as the trains are still moving :)

Whilst looking for the Wii Nunchuck Adapter at Toys Downunder, I came across RFID 'buttons' and an RFID reader that were compatible with the Arduino. Since I have the Arduino Mega, I knew I'd have pins/serial lines to spare, so I went ahead and added them to my order.

I bought the ID-12 RFID Reader and 2 RFID Buttons. I chose against purchasing the breakout board, as after reading the comments it didn't look like it would fit the ID-12 (only fitting the ID-20.) I've since asked Toys Downunder to correct this comment in case it really does, as soldering these readers is a pain. (Note, they have since updated the notes and the ID-12 does indeed fit. They also offered me a free one! I might act on that next time I go shopping there!)

Wiring up the reader was going to be pretty simple. I'd see examples of it wired here for a door lock and in the datasheet. I was a little confused as to which 'output' to use; there are two provided and I guessed right the first time (pin 9: Inverted TTL Data.) This output was fed into an RX port on one of the 3 surplus Serial ports on the Arduino Mega (Serial1).

After a quick bit of coding, I had the RFID reader picking up the RFID button reliably. You can find instructions on this from the Arduino site for another type of reader, but below is a quick code listing for getting it to work on the Arduino Mega. I wrote this with guidance from the previous door lock link and the Arduino site as well.

bool newData = false;
int cardData[16];
int idx=0;
void setup() { 
  Serial.begin(9600);  // Hardware serial for Monitor 9600bps
  Serial.println("Starting Reader..."); //show some activity
  Serial1.begin(9600); //ID-12 uses 9600!
}
void loop() { 
  while (Serial1.available() > 0) {
    cardData[idx] = Serial1.read();
    idx++;
    if (idx == 16) {
      newData = true;
      idx = 0;
    }
  }
  if (newData){
    newData = false;
    Serial.print("Found RFID device: ");
    for (int i = 0; i < 16; i++) Serial.print(cardData[i]);
    Serial.println(".");
  }
}

I've since read that external antennas can be hooked up, but creating one of these seems to be quite involved. Even though this ID-12 was the smallest reader available on Toys Downunder, there (after reading the datasheet) seems to be a slightly smaller one. It happens to be smaller since it doesn't include an internal antenna. Either way, if you choose to make your own, you may well be able to lay it in the trackbed. Otherwise, you can just shove a reader like this ID-12 into a trackside building or at the back of a engine shed to know which loco has arrived.

Initial testing showed that the Buttons could be read through my Thunderbird B-Train Shorty with motorised chassis; although the chassis wasn't powered at the time. I'll show the reader installed on a model railway in a future article.

modelrail.otenko Trains, computers, vintage, retro, model railways… the lot…

Tracking trains with an Arduino and RFID

Leave a comment

Random Photos

Search

Tags

Ads

Links - Click for details

Archive

Meta