user57327: I don’t know if this is even doable, but the idea is to have a large board with many (500+) locations where I objects can connect, each object having a single LED, and be able to illuminate the LED on any object, no matter where it is connected on the board.  So the requirement is that the objects can be moved to any of the connections on the board and and that the board can have any number if it’s connections occupied.
It seems obvious that each object would have to be able to identify itself and that each connection would have to be able to supply both a signal both ways and and provide power to light the LED.  On the code side, I’d need to be able to iterate through the connections and identify the desired object by some unique identifier and send a signal to turn the LED on and off.  I’m a .Net developer with little knowledge of electronics, but I’m willing to learn if it’s possible to do this.  I haven’t been able to find any arduino examples similar enough to provide some idea of where to start.  I don’t know if this is something that can even be done with Arduino or what components would be required if it is possible.
I’d appreciate any guidance on how this could be done or even suggestions as to what might be a better approach toward finding the guidance necessary to build this.

user2967: Your question is awfully vague.
There is a protocol called I2C that's commonly used for microcontrollers. It's a serial bus that has a data line, a clock line, power, and ground. That might meet your needs.
Each device on an I2C bus is supposed to have a unique address. You send commands to it using that address, and it doesn't matter where it is located physically.
I2C is designed to be a chain, and each device has 2 connectors that pass the connection on to the next device on the chain. 
I2C also uses a byte address, so you could only have 255 unique devices.

57327: <p>I don’t know if this is even doable, but the idea is to have a large board with many (500+) locations where I objects can connect, each object having a single LED, and be able to illuminate the LED on any object, no matter where it is connected on the board.  So the requirement is that the objects can be moved to any of the connections on the board and and that the board can have any number if it’s connections occupied.</p>

<p>It seems obvious that each object would have to be able to identify itself and that each connection would have to be able to supply both a signal both ways and and provide power to light the LED.  On the code side, I’d need to be able to iterate through the connections and identify the desired object by some unique identifier and send a signal to turn the LED on and off.  I’m a .Net developer with little knowledge of electronics, but I’m willing to learn if it’s possible to do this.  I haven’t been able to find any arduino examples similar enough to provide some idea of where to start.  I don’t know if this is something that can even be done with Arduino or what components would be required if it is possible.</p>

<p>I’d appreciate any guidance on how this could be done or even suggestions as to what might be a better approach toward finding the guidance necessary to build this.</p>
 2967: <p>Your question is awfully vague.</p>

<p>There is a protocol called I2C that's commonly used for microcontrollers. It's a serial bus that has a data line, a clock line, power, and ground. That might meet your needs.</p>

<p>Each device on an I2C bus is supposed to have a unique address. You send commands to it using that address, and it doesn't matter where it is located physically.</p>

<p>I2C is designed to be a chain, and each device has 2 connectors that pass the connection on to the next device on the chain. </p>

<p>I2C also uses a byte address, so you could only have 255 unique devices.</p>
