First of all, thanx alot for taking the time to answer =)
Can you check with a 5V arduino if it works better ?
Tried with a Arduino Ethernet board and then it works with two "splitters", three meters of cable and three sensors. Great! (Did not try with any more basically as I dont have any more splitters/cable avaliable at this time)
On the Fio, I did also try to move the 4k7 resistor to the end of the cable but without any luck.
I currently power the Fio from a 3.7v lipo battery. I have tried to optimize the code with regard to power consumption and have managed to get down to around 0.30mah during sleep. Basically the Fio is supposed to sleep for 5 minutes and then send the temperatures.
Would one solution be to change into a higher voltage battery and power the sensors from the battery? If so, any way to reduce power consumption during "sleeping"?
I am also planning to charge the battery by the on board usb charger. I guess this limits the voltage on the battery I can connect? any suggestions on battery?
Tomas