CAN Bus To Control Appliances On Multiple Floors Of A Building

This multistory home automation system coordinates appliance control across different levels of a building using a Controller Area Network (CAN) bus architecture. At the heart of each floor's station is an Arduino Uno board paired with a dedicated CAN module, which manages differential signaling over a twisted shielded pair wire to ensure reliable communication across long distances and through electrical noise. Each Arduino also interfaces with a 4x4 keypad for user inputs and a 5V relay module to switch connected electrical loads. When a user presses a sequence on a keypad, the local Arduino Uno reads the input and transmits a specific command packet over the CAN bus network. All other Arduino nodes receive this data, but the designated floor's unit processes the command and triggers its 5V relay module to open or close the circuit for that floor's appliance. The network relies on two 120-ohm termination resistors placed at the extreme physical ends of the twisted shielded pair to prevent signal reflections and maintain data integrity throughout the multistory setup.