I'd like to join in as i'm interested in creating a similar project. I started by hacking a solar plant light (see below) for power. My use case:
Creating Xbee zones that monitor sensor data from the front yard, back yard and indoor plants and send it back to a Pi. Each zone would have multiple hygrometers, a temp sensor, and a light sensor. Eventually I'd like for the zones to water plants as needed but i haven't figured out that part yet. Sensors in Mind:
1. Hygrometer /Moisture Sensor
analog temp sensor from Adafruit
3. Light sensors and solar gear
I hacked from a solar garden light for now but I think Adafruits solution is much more reliable.
4.MCP23017 ADC chip
(not a sensor) communicating through I2c back to the mother PiQuestions:
1. How would you send data back to the Pi? Can you use the ADC chip listed above communicating with the I2C protocol to expand the number of analog sensor inputs in each zone ? I haven't found any examples of connecting Xbee devices to analog sensors that doesn't involve plugging the sensors directly onto the xbee analog input.
2. What is the best way of implementing power saving mode. It seems the Xbee can wake up at pre-determined times, take readings, transmit them and go back to sleep. Can you use wake from sleep there?
I apologize if this information is better in it's own post and would gladly repost if you would like.