If you want to be flexible, maybe it would be a better idea to separate this into different modules, and connect all modules to a single sensor node via i2c:
- a module that uses IR
- a module that uses a magnetic reed switch
- a module that connects to the meter in some other way
Every module consists of its sensor (the reed switch) and an Arduino Mini Pro. All modules talk the same protocol over i2c. The i2c address could be made configurable with jumpers. And one central sensor node does the usual mysensors part.
Just an idea, I never tried that. But I think I'll give it a try too.
With this one could create a mysensors node with 2 IR nodes and one reed switch, if you move to a new house with different meters, you could simply replace one of the IR node with a second reed switch.