Automatic water pump

Projects General Guidance
21

What is the pump's current rating? You may only need a transistor to switch it.

1 Like
22

0.5-0.7A excluding any inrush current.

23

The site is from Greece.

Screenshot_2024-06-26-04-37-49-105_com.android.chrome
Screenshot_2024-06-26-04-37-49-105_com.android.chrome963×1359 62.5 KB

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24

I would go with the 7805 VR.
that thing is rated for 1amp.... more than enough to power the relay vcc and the arduino on it's 5v pin if you wanted to.

25

Should I power the Arduino from the regulated 5 volts then or from 12volt DC jack?

26

I don't think that it matters too much for how basic this is.
Also post21 makes a good point.
a transistor and a couple resistors would do this pretty easy. and you could add PWM if you needed to for any reason.
the PWM would allow you to ramp the pump at start up and get rid of bigger inrush current

27

Well I ordered the relay so I may as well use it. Do you think if I don't do anything actively to reduce the inrush current, does the 2A 12VDC PSU fits well?

28

i think the 2amp power supply should be enough for this as originally listed.

I use these sometimes. they would also be a good fit for this.

Kyoto Electric KF0602D DC-to-DC Solid State Relay, 32 Volt, DC Input, 2 Amp, 4-Pin, 1.4"L x 0.3"W x 0.9"H: Electronic Relays: Amazon.com: Industrial & Scientific

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29

Thanks for the recommendation! But it is a little expensive compered to the relay. I will keep the solid state relays in my mind though.

30

Project Update:
After all wonderful people helped me with their answers I modified my project.
12 VDC would go directly at the relay and a regulated 5V generated by a voltage regulator from the 12 V PSU will power both Arduino and the relay. Also the new psu will be 12VDC 2A.

1 Like
31

Are you planning on being around to see if the plants actually get watered?

32

Hello general-arduino-007

Welcome to the worldbest Arduino forum ever :slight_smile:

Post a circuit diagram with all the components used.
A picture is worth more than 1000 words.

33

Only for a few days then I will be gone for a couple of months.

34

Is someone going to be there to make sure the system works? Will it work during a power failure? Wouldn't it be nice if you arranged for some feedback from the system as to it's working status?

35

I am thinking about all the problems that may arise and power outage is one of them. Also no one will be here to restore it's function so maybe if should have some auto-restoration property. I am in the process finalizing my basic schematic and then I will modify it for some safety - stability features. Also quick question, if an Arduino is turned off, when it is back on should the code run again without any problem?

36

Schematic Update:

IMG_20240626_085659
IMG_20240626_0856591920×1351 161 KB

37

Here is the schematic.

38

I forgot to mention:
(The pots are in my balcony.)
(I will not use any sensors for soil humidity, the plants will be watered specific times based on real time clock)

Now let's think what can go wrong:
Possible Problems:

  1. Environmental:
    -Strong Wind
    -Rainfall with wind
    -Third party interactions (birds, insects, airborn objects..)

  2. Mechanical
    -Pump fail (stuck open/closed)
    -Relay fail (stuck on/off, if it is mechanical)
    -Pipe/water connections fail

  3. Electrical
    -Power surge/outage
    -Arduino fail
    -PSU fail
    -Voltage Regulator fail
    -RTC fail

  4. Software

  • Code glitch/corruption
  • Real time isnt valid

I am interested in solutions-protections for 3, 4 categories of problems and also about the pump (category 2) stuck into an ON state...I don't want my balcony to get soaked.

39

Yes they do.
Commonly known as inrush current.

40

I wouldn't depend on those cheapy toy relay modules for long term service, I like @horkey_williams solution. Don't forget a kickback suppression diode in parallel with the pump to suppress switching spikes.

2 Likes