How do I detect 1-Wire peripherals without constant polling?
If memory serves, one-wire devices define a reset pulse is any low pulse longer than a specified duration (I think about 600us) with no maximum duration.  Being unplugged for four months and then having voltage applied would qualify as a 10,368,000,000us low pulse, which is certainly longer than 600us.  Consequently, the devices generally assert a "presence" pulse shortly after power is first applied.  Depending upon contact bounce, it is possible that touching a device may not cause a clean reset, in which case one might possibly not get the "present" pulse, but I've found that triggering on a falling edge triggered by a remote device seems to be pretty reliable.