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greenhouse_water_fertilizer_basic.ino

This Arduino app is a basic timer I used to run a water pump for my greenhouse at timed intervals.

 

It turns on a relay to control a water pump. I recommend getting a properly approved setup if switching line voltage, or stick with the safer 9 or 12 volt pumps.

 

The second relay controls a fertilizer pump. In my case it's a smaller 9v pump that injects liquid fertilizer into the watering lines. Shut this pump off before the main pump so the lines get flushed with clean water at the end of the run.

 

You don't need to hook up the second relay if you don't need/want fertilizer injection.

 

Also, MIT license - in summary, feel free to use it for anything but don't blame me for anything image

 

Enjoy!

-Nico

ntewinkel
  • in reply to neilk

    ps, the Delay call is just to sleep the chip for a second, it's not used for counting time. The internal millis() call does that.

     

    One thing that might be nice to have is to actually sleep the microcontroller completely for much longer times, like just in time to turn on the relays - that would allow for better power management and maybe let it be run on solar. Of course, then you might want it to use a sprinkler valve on pressurized water instead of a pump, because running a pump will consume far more power than the little Arduino.

  • in reply to ntewinkel

    To make it not offset by the watering time, simply add this line at line 40, after setting fertilizer_time:

    waiting_time = waiting_time - watering_time;

     

    That should keep it running all summer long and still stay within a few seconds of the original starting time.

  • in reply to neilk

    Right, I think I learned about the timer libraries *after* having done several projects this more manual-labour way!

    However, counting milliseconds is not too cumbersome and does provide an interesting learning opportunity.

  • Hi Nico

     

    Neat project.

     

    I agree it's not super accurate but it is definitely fit for purpose! Why does it need to be more accurate?

     

    However, if you wanted the opportunity to do more with the Arduino, you could look at Simon Monk's Timer Library. I've used it in a number of simple applications, instead of using the Delay function - it's very useful.

     

    Neil

  • ps,

    It's not super accurate for time, but by the 80/20 rule works plenty well enough image

    At quick glance it looks like the start time is offset by the run times, but you could adjust the wait time to a number that subtracts the run times.