Can anyone help me with designing a circuit diagram for a project?

I am creating a self watering system for plants. I have found a diagram for a water detection circuit which illuminates an L.E.D when there is enough water in the soil. However, I would like to modify it so it activates a servo to open a pinch valve then when there is enough water it returns the servo to it's original position. I have 3 problems. The first problem is I'm not sure how to create the circuit that activates the valve. I know I need a micro controller and a servo, however, I have no idea of the exact components I need or how to wire them up. My second problem is that I don't know how to integrate the two circuits together. My final problem is I'm unsure of how to program the micro controller.

Here is the water detection circuit diagram.
http://www.electronic-circuits-diagrams.com/homegardenimages/3.gif

Any help would be greatly appreciated.

rickharris6 years ago
http://www.picaxeforum.co.uk/showthread.php?t=12266&highlight=watering+system

may help you out.

kelseymh6 years ago
You could be even simpler. Put the LED from the original circuit into a little box with a photodetector. Use the photodetector to trigger a non-latching relay that opens a valve. When the LED goes out, the relay opens, turning off the valve.

In terms of being able to diagnose and repair problems, avoid programmable electronics when a simple circuit solution can be built.
And if it's using a plumbed water supply, make sure it's got a fail-safe (power off = valve closed) or second sensor higher up saying 'water shouldn't be this high, kill everything'.