home automation

I want to control about 11-12 relay module (with optocoupler) with my Arduino mega/uno have both, at first I was thinking to go with ardroid but it was not suitable for my implementation as I want to control it over my network with and android app if possible or browser will be the last resort...

- Bought from aliexpress. - Checked once for working of unit. Unused after that. - It has modbus output. Useful for interfacing with pi and arduino.