OpenSprinkler › Forums › Hardware Questions › OpenSprinkler Zone Expansion Board Wireless Communcation › Reply To: OpenSprinkler Zone Expansion Board Wireless Communcation
If you are referring to the current version: OpenSprinkler 3.0, the expander uses I2C to communicate with the main controller, so the question is really how far I2C can go. I did some Googling:
and it seems going 100 feet is definitely possible, by reducing I2C clock speed.
At the moment, the firmware uses typical fast-mode I2C speed, which is 400kHz:
it can be lowered to any clock speed you want (though below a certain number you may also need to modify Arduino’s I2C library because it may be imposing a lower bound on how low the clock goes).