Hi,
Yes, it's generally recommended to limit an I2C bus to about 1 metre, but sometimes it can be pushed further if necessary. Firstly, use twisted pair(s) cable (e.g. CAT5 network cable) not screened/coaxial, to keep the capacitance lower. Pullup resistors (on SDA and SCL) somewhat lower than the normal 4k7 may help; also the software may be able to run the I2C bus in "Slow" mode and/or I believe that bus extender chips are available.
The Rain sensor and Anemometer indeed use simple reed switches, so that long cables (again preferably twisted pair) should not be a problem. However, extending the cables of a "normal" Fine Offset station can cause difficulties, because the transmitter uses a high pullup resistance (to each reed) to save battery power. In this case even a small amount of water (rain) in the cable/connectors can effectively "short out" the switch.
Similarly, the FO Vane uses high value resistances to indicate certain directions so some care may be needed to avoid water ingress. But the "precision" of the FO Vane is such that you probably wouldn't notice anyway.
The Weatherduino Solar sensor uses quite low (analogue) voltages, so the cables should be kept moderately short to avoid "pickup". In this case a coaxial cable might be preferable. If you have to use a long(er) cable, then putting just the PV panel and its load resistor at the far end might be best, because this is a low impedance interface.
Cheers, Alan.
Yes, it's generally recommended to limit an I2C bus to about 1 metre, but sometimes it can be pushed further if necessary. Firstly, use twisted pair(s) cable (e.g. CAT5 network cable) not screened/coaxial, to keep the capacitance lower. Pullup resistors (on SDA and SCL) somewhat lower than the normal 4k7 may help; also the software may be able to run the I2C bus in "Slow" mode and/or I believe that bus extender chips are available.
The Rain sensor and Anemometer indeed use simple reed switches, so that long cables (again preferably twisted pair) should not be a problem. However, extending the cables of a "normal" Fine Offset station can cause difficulties, because the transmitter uses a high pullup resistance (to each reed) to save battery power. In this case even a small amount of water (rain) in the cable/connectors can effectively "short out" the switch.
Similarly, the FO Vane uses high value resistances to indicate certain directions so some care may be needed to avoid water ingress. But the "precision" of the FO Vane is such that you probably wouldn't notice anyway.
The Weatherduino Solar sensor uses quite low (analogue) voltages, so the cables should be kept moderately short to avoid "pickup". In this case a coaxial cable might be preferable. If you have to use a long(er) cable, then putting just the PV panel and its load resistor at the far end might be best, because this is a low impedance interface.
Cheers, Alan.