Noob and openhab/home automation

I’ve recently come across openHAB and it seems fantastic. I’m wanting to play about with home automation. I’ve been looking at using an arduino based etherten or similar for the controller and I was wanting to have it use a wifi module to speak to other mini pro’s to then toggle relays, detect mail through letter box etc.

Are there ways to use a RPI with wireless capabilities on a tight budget? The arduino route looked quite appealing mainly because of the price.

I’d love some help or pointers as I’m really getting frustrated trying to figure this out.

Take a look at the MySensors site.

I use combination of RPI - Model 2 with mostly zwave devices being controlled. While these can seem expensive, for stock items like mains-attached devices, I doubt you could safely and cost-effectively do replacement engineering. For custom sensors, is a “go-to” site.