1-wire cabling
From Wiki
Layout
1-wire networks use actually two wires, one for data and one for ground. The used DS9440R USB adapter has an RJ-11 adapter (6 wires) of which the two middle ones are used by the network and the outer pins are unused.
In my setup we have CAT-6 cabling in our walls with RJ-45 sockets in every room, so it was decided that the existing cabling should be usedalso for the temperature cabling. As each room has two sockets it was an easy choice to dedicate one of the sockets in our office room to the 1-wire network. From the office the cabling goes to a central wiring cabinet and from there it is split into two paths.
All sensors are always installed in parallell and the total network can be up to 300 long and with a lot of sensors. Using many sensors reduces the total practical length that can be used for the network.
Sensor location
Our network currently uses three sensors:
- one in the office room directly after the USB adapter. It measures the temperature in the office.
- one in the room where the central wiring cabinet is. The sensor is outside the cabinet.
- one sensor that measures the outdoor temperature. It goes from the central wiring cabinet out along with some other wires and is mounted under the roof of our veranda, out of direct sunlight.
Future enhancements
Sensors should be mounted on a single long wire and not in a "star assembly" as we currently have. The extra wiring will cause echoes in the network and can cause misreadings and faulty operation. As having a single wire span all sensors isn't really suitable for us a central 1-wire hub will be installed in the central wiring cabinet. The hub allows a star formation for the sensors and makes it possible to have up to six other sensors on own wires without any echoes and misreadings. Currently the hub is ordered but it has not yet arrived.
