Self Plant Watering System

I have been working on this system for a bit. Right now I control the relays by time. When they come on and when they turn off. All this seems to be working great. My question is about not watering plants when it rain or is going to rain. I have been think about Humility. I really do not know how I can determine if it is going to rain or it it raining Looking for ideas of sensors or if someone might have an idea on this. Thank You for the help

Sprinkfitter

You cant determine if its going to rain, but you can determine if it is raining by using a rain guage. Most are the tipping bucket variety and need around 1mm or more of rain to detect raining.

Thank You for your feedback. Hope I get more responds.

If it is raining, then you can turn off the automatic system until needed again. Further, if you measure the amount of rain, that (and temperature/wind measurements) should allow you to estimate when water might be needed.

You can also measure soil moisture content, but as a search through this forum will show, most people report difficulties of one sort or another.

Soil moisture sensors are an option. Humidity and temperature sensors give you an idea on the amount of evaporation, so how much water your plants need. The local weather forecast (some services may provide an API, otherwise you have to web scrape) can give you a forecast of whether it will rain (but not how much). Rain gauges can tell you if it rains, and how much (if it's just a few drops after a hot, dry day, you still have to water). Even brightness sensors may help tell you if rain is coming, as it tends to get darker before rain (thicker clouds).

wvmarle: Soil moisture sensors are an option. Humidity and temperature sensors give you an idea on the amount of evaporation, so how much water your plants need. The local weather forecast (some services may provide an API, otherwise you have to web scrape) can give you a forecast of whether it will rain (but not how much). Rain gauges can tell you if it rains, and how much (if it's just a few drops after a hot, dry day, you still have to water). Even brightness sensors may help tell you if rain is coming, as it tends to get darker before rain (thicker clouds).

The soil sensors I thought would be a great idea so I tested 3 of them in some plants around the house. They lasted a couple of weeks. Not a reliable situation on the test I have done. Maybe someone has had better luck with them and could share their findings. I am looking at quarrying info on local weather report Throwing a few if maybe hope so and than bingo come out and decide when it will rain or has it rain. I wonder if any one has done something like that with the Arduino??

Thanks for the feedback Sprinkfitter

There are many kinds of soil moisture senors - usually based on conductive or capacitive sensing. The first will corrode fast if you keep them powered at all times.

wvmarle: There are many kinds of soil moisture senors - usually based on conductive or capacitive sensing. The first will corrode fast if you keep them powered at all times.

Would you have a recommendation on witch one to use.