Stan;
Got the address -- I'll get the ITAD in the mail in the morning.
I changed the Title for the thread as you suggested and added 2 keywords.
The first thing I should make clear is what I'm trying to do. Right now I'm only concerned about 3 very different engines: GG1, GP9 and 2-8-0 Steamer. I have 4 of the 2-8-0 Steamers but for now I'm ignoring that fact. Therefore, I hope to distinguish between the 3. I have no plans to acquire any more engines.
As for Train detection using IR -- I use 2 separate IR detection mechanisms; 1 to tell me the train is approaching the crossing so I can send a command to the TIU to tell the engine to sound the crossing signal; and the 2nd IR detection mechanism is used to control the crossing gates. Currently, I can handle the gates when the train approaches from either direction. I don't currently have anything setup to tell the engine to sound the crossing signal for the other direction.
I have 1 track and 1 crossing.
If I had the engine number (that's internal to the engine, which the TIU uses to command the engine to do something), I could tell the engine to sound the crossing sound regardless of which of the 3 engines it is that is now approaching the crossing. Right now, all I can do is limit my capability to one particular engine or I could send the command for the crossing signal to all 3 engines.
Sending to all 3 is out.
I have currently put the CV approach to Identification on the back burner. It is doable to distinguish, by engine number, between 2 otherwise identical engines, but it gets a little involved.
So, that leaves me to think about RFID.
However, your comment about the 'roll your own' transponder got me to thinking about it. As I understand it, you are essentially saying I would put a very tiny IR device like a TV remote under each engine but instead of only sending when a button is pushed, as in the case of the TV remote, this 'special' IR transmitter would send continuously and it would be up to the IR detector to make some sense out of what it received. To do that, I think you've suggested the IR stream would be sent to a PIC kind of processor to decode it.
I like it.
I'm going to give it some more thought.
Thanks for the discussion. I'm going to get the Adafruit micro RFID tag and the reader first and see how far I get with that approach.
Ray
