On Wednesday, 6 March 2013 10:03:14 UTC, Tim Watts wrote:
On Wednesday 06 March 2013 09:51 Andy Champ wrote in uk.d-i-y:



On 05/03/2013 19:27, Andrew Gabriel wrote:

I use dallas 1-wire digital thermometers around the house.

These are not wireless, and require a twisted pair



Am I the only person trying to work out how "1-wire" means twisted pair?



Andy



The name is erroneous - a marketing gimmick - it means "1 wire for +ve power

and data combined" - you still have a 2nd wire for ground...

There are actually three wires! Ground, data and power. Some 1-wire devices can derive enough power from the data wire to run without the power wire, but not all can. 1-wire refers to a single wire being used for data/signal, unlike other hardware protocols which require data + clock at least.

I've got multiple 1-wire temperature sensors hanging off my Raspberry Pi. Some distros for the Pi (e.g, Occidentalis) allow 1-wire devices to be connected to a GPIO, but I've got mine working off an I2C 1-wire bus master, which then makes the sensors available through a file-system interface.

dan.