If you use I-Button I encourage you to look carefully at how you wire up the control cable. If you try to use the cable out over say 10 feet from the microcontroller then you should consider a shielded cable. A colleague of mine did an 1-wire system using the Dallas temperature sensors and was trying to do 30 meters of cable. The 60 Hz AC pickup in the cable casued him huge problems of noise on the cable.
Michael Karas