[beagleboard] Arduino to Beaglebone serial connection

I am trying to enable serial communication between an arduino and beaglebone black, for a home automation system. I got it working once(the beaglebone printed data it was receiving) but hasn't worked since. I followed this

Re: [beagleboard] Arduino to Beaglebone serial connection

This might not be your problem, but it's important that both boards share a common ground. The picture shown on the link you've given is missing a wire. The two blue wires shown at the end of the breadboard are meant to be connecting the two ground rails but don't as there is no wire bridging the