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.

Any help would be greatly appreciated.

rickharris6 years ago

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'.