Here is my current project and entry for the Hackaday Prize:
http://hackaday.io/project/2375-Garden_automation_and_sensor_network
The main purpose originally was to have temperature monitoring of a small outdoor greenhouse, but then I decided to expand it from there. For more info look into the project page via the link above.
Description originally from my hackaday projects page:
This is a project to create a small network of sensors in the garden, and possibly some automation. The sensor data will be logged on an embedded Linux server (probably a Raspberry Pi or BeagleBone) and displayed on a web page. One such application for use is within a greenhouse, which may need to monitored in case it gets too hot for the plants, then venting of air could be automated, or the web page could alert the gardener. The nodes will consist of various sensors (temp, Humidity, soil moisture, etc.) attached to MSP430 microcontrollers which communicate using nRF24L01+ 2.4GHz tranceivers. Some will have Solar panels and rechargable batteries and others may have just a 3V button cell, but will last long by using the low power capabilies of the MSP430 and nRF24L01+.
Final code github repository (for code when done):
https://github.com/emdarcher/Garden_automation_and_sensor_network
Prototyping code location on github:
https://github.com/emdarcher/msp430-nrf24l01-testing/tree/master/sensor_comm
YouTube video explaining the system (required for Hackaday Prize entry):
Here is a pic of a prototype node, using internal temperature sensor and calibration data, as well as a HS1101 relative humidity sensor circuit with 555 timer.
Prototype node and receiving launchpad to the left:
Simplified diagram of Greenhouse node:
Here is the system diagram:
