Back in September, I was thinking of implementing a single track signalling system using some PIC's, custome circuit boards and a lot of blood sweat and tears... Then one day, best mate pointed out that you can buy Arduino clones on ebay for stupid prices...

Just how stupid? Try £2.33! Each! Including P&P! From China.... It takes about two weeks for them to get here, but there's no rush, so that's fine...

So five were duly ordered, the correct driver was located and they arrived a bit before Christmas...

One big issue was that they needed to talk to each other with as few wires as possible. Having a gander around the Wibbly Wobbly Webbie thing produced the answer... Configure them in a ring: If an Arduino generates an event (e.g. A train passing), it shoots a message to the next one, which then takes any action requires and forwards it to the next. All the way round untill it makes it back to the sender, where it's stopped (or "Eaten" as I call call it).

So today I started to actually develop the software, I have written the low level bits which allow the collection of Arduinos to work out how many there are in the circle and have written some driver software to switch signals to the correct aspect...

I have made one big assumption: The station at the end can take an infinite number of trains... Fair enough? How can I mak this realistic (within limits)?