If you happen to be a railway geek, you may know this Intellibox:
Between the control computer and the railway is Uhlenbrock’s Intellibox (German site). Its RS232 interface supports Märklin’s P50 protocol, plus extensions called P50X. The extensions include an event system for acquiring information about changes in the railway state. The most important use for this is reading track sensors, but it can also be used to keep the program in sync with other control devices.
It is ment to be made out of modules (for sensors, turnaout control and so on), but as a [spanish twit] adviced me, down at [databeaver's domain] they found a way mimic the begaviour of these modules, wirelessly. (nice conbination between *BELOVED* Arduino mini and Xbee)
I’m starting to make and use some custom hardware components based on the Arduino microcontroller boards. The first one is a wireless s88 transmitter/receiver pair using an XBee radio module. This allows me to get rid of long sensor wires and it has potential to be cheaper than Märklin’s (horribly overpriced) s88 modules.
The firmware source code for both the transmitter and receiver can be found from SVN. Schematic for the transmitter is below; the receiver can be connected directly to the S88 bus (see the source file for pinout).
Via [databeaver's domain]