I’m researching for my first electronics product, which is to have my PC control the electric Somfy roller shades for my windows. I have 5 roller shades and each has a wall button which is also an RF receiver. I have an RF remote which sends out a signal to one or all wall buttons, telling them to go up, down, or stop. I expect sending the RF commands would be difficult, so I purchased an extra RF remote and I hope to have some device (an Arduino?) simulate button presses (there are 5: up, down, stop, next, previous).
I’m a programmer by trade. While I’ve dabbled with simple electronics long ago, I would greatly appreciate a bit of hand holding. 
I do have a DMM, so there’s that!
While a [physical solution is amusing, I think there is probably a better way. My first thought was to use electromagnetic relays. After some reading, I’ve come to think this is also not terribly elegant for such low voltage. I considered solid state relays, but found they only work with AC and don’t work for low voltage. Next I came across optocouplers, and this seems like a very promising solution. I also read a bit about using transistors, but it seems best to keep the Arduino and remote circuits separate.
Are optocouplers the way to go? How would I wire them up?
The main downside to hacking the remote like this is that it won’t work correctly if the state of the remote doesn’t match the expected state. This shouldn’t happen since my device is the only thing manipulating the remote, but who knows. A workaround is to power cycle the remote so it has a known state, then apply commands. The remote runs on two AAA batteries. Could I use an optocoupler to power cycle it? In this case I’d want the circuit normally closed and the optocoupler would (somehow) open the circuit briefly. How might this be wired?
Next is what to base the device on. RaspberryPi? Arduino? RPi seems like it has more functionality than I need for such a specific task, so I’m leaning toward an Arduino. If so, which board to use? I’d like it to have WIFI for these two reasons: 1) I’d like my PC to control it via HTTP, and 2) in the future I’d like do a similar hack for my AC’s IR remote and to have line of sight to the AC, it needs to connect to the LAN via WIFI. It seems Yún and TIAN have WIFI, or I could get an Uno and a WIFI shield. Are there other Arduino boards with WIFI or any recommendations on which to choose?](https://youtu.be/wFor8gb4Tz8)