Water level gets too low=pumps more water into reservoir

I have no idea how to make this simple as possible.

situation is that my plants have a reservoir where water lowers after few days.

I need a sensor that when its out of water example, the pump pumps in more water from bigger reservoir.

What is easiest way to do this with arduino? and what kind of sensor I would need?

Any examples or codes are appreciated too.

I have arduino mega and motor and sensor shields.

Could it be as simple as two jumper cables heads when submerged close circuit and when water level raises, circuit opens=pump starts to pump more water?

You either need two sensors - one to tell when the water level is higher enough (to switch off the pump) and another to tell when the water level is too low (to start the pump).

Or, you may find it sufficient to have a single low-water sensor and run the pump for a specific length of time.

In any case it might be wise to have a limit on how long the pump runs so that a sensor problem does not leave it running permanently.

You could experiment to see if a sensor could be created with two wires which are bridged by the water when they are submerged.

If you have no experience of the Arduino I suggest you study several of the example programs that come with the Arduino IDE. There are also plenty of online tutorials.

If you want the pump to run for a certain length of time, or if you want to make sure it stops after a certain length of time you will need to use the millis() function to manage the timing. This is illustrated in Several Things at a Time


Why not use a simple everyday float switch?

I was thinking that I could use webcam to see my plants and water level but I would need a code and advice bit how I can make bluetooth controlled push button.

Example I see on cam that water is low, I use another computer at home via internet.

Arduino is bluetooth connected to that computer and when I push button, arduino puts motor on.

I already know how to light up a LED over bluetooth.

Yeah i am noob..

also realiable and small float switch place where to buy, interests me.

look in your toilet. there is a float that lowers and lets water in, then raises (floats) and shuts the water off.

as Robin2 said, a pair of float switches. one at the low point, one at the high point.

Look at any sump pump that has the motor outside of the pit. The float is guided between two loops. the float rises when filled, and at some height pushed up on the switch to stop the pump.
water drains and once the float lowers the arm, it trips the lower switch to start the pump.

you can use a sonic sensor to monitor the actual water level.