The thing I'm trying to make is the following:
There are blocks that represent certain movements (left/right turn, forward, etc.) When the blocks are arranged in a certain order and an activator button is pressed, a car will move according to the movements specified by the order of the blocks. So basically it consists of the blocks and the car and the two communicate through XBee.
Previously I've had a board with slots for the blocks to go into and used potential dividers to recognize the block types. However, I want to do away with the board and connect the blocks directly to each other. In this case, I can no longer use the potential dividers, because there would simply be too many wires and all of them have to go through the blocks themselves.
I've considered putting XBee's in each block, but that would be too expensive. I've also thought of assigning barcodes to each block and scanning them with a sensor. But I'd prefer if the user involvement in reading the blocks was minimal.
I probably did a bad job in explaining so feel free to clarify anything. Basically, I'm looking for any alternative method to recognize the block types. Any examples of products in which this type of technology is employed would also be helpful.