after a few "years" of break I'm in love /w Arduino, again. At the same time I'm in love with TP-Link TL-WR703N router, too. Altogether this is the result:
This is the original project:
TP-Link TL-WR703N with OpenWRT
Arduino with DS18S20
Every five minuets the Arduino sends temperature data via serial/USB to router. It gets the data and posts it to Xively (ex COSM ex Pachube ex ???).
Furthermore it writes data to text file that a script reads out. Google Charts shows it then.
Simple as is.