I am building a project that will measure the temperature in the different levels of my home and report back to a picaxe. Is there a maximum length of cable for 1-wire devices? Is there any special circuitry that must be used to protect the chips?
I recall reading the spec in one of the docs. Possibly the DS18B20 temperature. It gave me confidence to have an 12 metre run within my house for measuring roofspace temperatures (solar heating project).
I have used several meters with no problems. Would use 5 Volts to power them (not parasite power). The voltage drop is only quite small because of the very low currents but use cable of twisted pair and/or shielded, eg; Cat5, you must avoid any induction/noise from high voltage sources running nearby. I used 100mA quick blow glass in-line fuses to protect the circuit in case of a short occuring due to any damage to cable run or sensor. You could experiment by connecting up the sensor with clips to the end of a long length of cable coiled in the same room. There is more info if you go from this page to home/links/Peter Anderson/ scroll to sample routines/a three point monitor using DS18B20. He quotes success using 200 ft of cable. Anyway, as the others say- let us know how you go!