Irrigation system using nothing but the power of the gravity

Hello guys.

I'm trying to create a system involving a soil moisture sensor and an eletronic valve. I have seen some projects on the web using water pumps and other equipments. I would like to build a simple project to irrigate the plants on my home. I'm thinking on using some system using the power of gravity. Have some container above the plant with a hose to direct the water to the vase. I'm trying to find the best hardware to aid me in this mission but without any lucky so far.

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The sensor would be in the vase and there would a hardware to open the valve so that the water could fall down to the vase. I thought about using a ServoMotor to control the OPEN/CLOSE of the water flow but the ServoMotor isnt fast enough to shut down the water in milisecond since when you open the valve the gravity will make a lot of water run down.

My question to you is: What piece of hardware or ingenious way I can acomplish this task? I'm a newbie in the world of Arduino. This is my third project so far. Be easy on me :) :)

Two options (i can think of right now)

  1. Use a servo but limit the amount of water. You probably don’t want massive amounts of water at once anyway.

  2. Use an electronic valve / solenoid valve.

Search on "drip irrigation". Only the roots need watering.

If you look on Ytube there are lots of vids showing how to water plants from simple plastic bottles etc, no electronics at all.

You can use an aduino with a soil moisture sensor and valves, but think the little peri type of pump motors on ebay are so cheap its a better option having the water reservoir alongside or below the plant.

If you use this type of sensor it has both analogue and adjustable digital outputs so you could use just a transistor to switch the pump on. Been testing one of these this week, seems quite good, if the sensor does not corrode etc. Rather than powering all the time, its powered from a digital pin for just 1 second to take a reading then off for 10 mins.

http://www.ebay.co.uk/itm/Soil-Hygrometer-Humidity-Detection-Module-Moisture-Sensor-Arduino-3-3-5V-/142139262063?hash=item211829046f:g:cOMAAOSwTA9X9MiJ

or now with relay built in

http://www.ebay.co.uk/itm/5V-Soil-Temperature-Moisture-Sensor-Soil-Hum

I'm thinking on using some system using the power of gravity

Is there a reason that you want to use gravity? Even a solution using gravity is still going to need a separate power supply from the Arduino for the solenoid or servo to open and close the valve, so if that was the reason you might as well consider a pump.

davidrh: I'm thinking on using some system using the power of gravity

Is there a reason that you want to use gravity? Even a solution using gravity is still going to need a separate power supply from the Arduino for the solenoid or servo to open and close the valve, so if that was the reason you might as well consider a pump.

I have a shortage of money to use while I would like to develope my skills in Arduino. Using a pump would require more money while the ServoMotor and other hardwares I have at my disposal from previous projects.

If you want it with what you have, then use the servo and a valve (assuming you have a valve too) and restrict the water flow.

Otherwise, both a pump and a solenoid valve are both super cheap in China :)

...since when you open the valve the gravity will make a lot of water run down.

What??? It's easy enough to slow-down the water flow... A smaller tube/pipe or seal the end of the tube and make a very small hole. (Drip systems have small holes, and maybe there's something else mechanical to slow-down the flow when the pressure increases.)

P.S. I've never used a moisture sensor but I get the impression that they can be unreliable (maybe they corrode) so you might also want a backup "flood sensor".

Using a pump would require more money while the ServoMotor and other hardwares I have at my disposal from previous projects

Perhaps list what you have available and your budget, as your original post stated:

I'm trying to find the best hardware to aid me in this mission

Servo motors and valves will be more mechanically complex to implement than solenoids or pumps.

You will need to do some mathematics to get the same amount of water as the volume in the bottle goes down.

Paul

Hi, Instead of a valve, use a piece of silicon tubing and pinch it off with the servo. If rate of flow is not a problem, ie slow to dripping, the tube can be quite small, say 3mm diam, easy for a cheap servo to pinch.

Just a thought, I've seen enough peristaltic pumps in the last 3 weeks, not me the wife in for complications of diabetes.

Tom.... :)

TomGeorge: If rate of flow is not a problem, ie slow to dripping, the tube can be quite small, say 3mm diam, easy for a cheap servo to pinch.

Exactaly what I was thinking of using. I have started experimenting with the tubes to see what is the best for my situation. I'll post the project finished in here when it is finished.

Sorry to hear about your wife. I hope everything turns out okay.