I’ve wired up a nRF24L01 directly to the expansion connector of a Raspberry Pi. It does not use any of the pins that OSPi uses, so no coflicts there. I’ve also tested basic one-way communication to a remote atmega168 with another nRF24L01. So far so good.
I use the wiringPi library and a bit-bang SPI communication routine on the Pi written in C.
Now for my question to Dan and Ray. Have you defined the radio data payload structure yet? Sending [zone_num,seconds_on] from the host to the remote for immediate execution would seem to be the minimum. Is the OSBee going to have multiple zones and inputs as well as outputs?