Automated water sprinkler system that saves water by only allowing the sprinkler to run if it is really needed. Uses a moisture probe buried at a certain depth to detect the water content of the dirt. When it comes time in the schedule to water, it checks if the dirt is already wet from previous rain, etc. first. If already wet it will not sprinkle and save water. Otherwise it will water on schedule normally.
Based on the existing idea from http://hackaday.com/2011/11/19/python-powered-sprinkler-system-wastes-no-water/ This idea doesn't waste water by checking the rain gauge. If it rained enough don’t turn on sprinkler. If rain is in the forecast make it wait a little bit before checking the rain gauge then turn on sprinkler.
Would it make sense to use all three: moisture probe, rain gauge, and internet weather forecast?
Is this the best moisture probe out there we can hack? Moisture Probe
Let me know if you have any ideas to make this work better, cheaper, or faster. Constructive criticism is highly encouraged.