I have designed a board based on Arduino for home automation use.
The card can be placed in a case din (208x86,5 mm).
The "master card" is equipped with a chip arduino atmega-328p-au and controls 8 bistable relays with 16 ampere and accepts 8-button input
The "slave card" does not have the chip but can be controlled by the master control for other 8 relays and accept other 8 buttons.
Each master board can control up to 7 slave cards.
Through the use of specific i2c buffer (P82B96 or pca9600) I can control the slave cards up to 100m away from the master.
Adding another master card, I can control other slave boards 7.
I can add up to 96 master boards in a network, 112 i2c addresses reserved minus 16 addresses: 8 addresses for mpc23017 (output) and 8 addresses for PCF8574 (input), and 96x7 slave boards.
All cards can communicate with each other. someone can affect my project?
You'll also find files of the programs used in the demonstration posted on youtube: http://youtu.be/x3JpeyEOX2c