Thank you very mcuh for your reply, i'll defintely take a look to the sonoff devices if it can suits my need. In the same time regarding eclettis, i contacted them and their reply is that : *Our commands for home automation systems are simple normally open commands so they can be connected to every system. Just pay attention before connecting the device: ensure that the working voltage is properly configured in order to avoid to damage the device. * So i'm still looking in the same time for battery powered 4 way transmitter and corresponding receiver for DC system, on the top of that everything is dimmable led light...