Using a bank of about 30 tiny261's on various remote units located within about 20 feet of one another (a 20 foot TOTAL cube, they are moving around). These units are high power (multi amps), and there is plenty of power to spare.
One unit is the master & needs to individually control 1 or 2 digital lines (possibly tiny 261 pin outputs) on each individual unit (thus no lines are common). The master to line control latency should be no more than 10ms (typical on/off, fwd/rev), and the line to be controlled is randomly selected.
It would be nice for the remote units to be able to send 1 or 2 bits of status back to the master, but this is not absolutely needed.
I'm thinking some sort of Bluetooth-uart or Zigbee-uart module scheme would be best. I'm not sure if the Bluetooth modules out there can support 20 remotes (or be able to quickly change linkage to the requested remote). Zigbee seems to do this inherently.
Does anyone have a recommended module? I'm looking for something relatively 'plug & play', not requiring a chip software stack to use up all my tiny261 code space.