I am working to create a system where I can control multiple relays while reading if there is a successful connection before I fire the relay. Here is my plan:
I want to have a base Arduino to control all of the smaller modules. This will consist of some kind of responsive control method (so I can control it from my iphone); however, I am not sure what kind of shield I need. I want to use bluetooth so I do not have to have any routers or IPs assigned. Nor am I sure on where to start for the code.
Each module will consist of a shift register (74HC595), a relay bank, a shift-input register (CD4021BE). Each one will be about 40 feet apart. I want to be able to add more modules, what is the limit on the mega?
Sorry if this isn't very clear!