Farmbot : supplying water from Water Tank

Hi the farmbot family !

I’m part of a team of french students which has decided to build a farmbot in order to open a debate on urban agriculture. To do this we plan to set the farmbot indoor and we have no pressurized water hose hookup !

We have understood that if we were putting a water tank it needed a water pump. There is one recommended in the documentation , but does it requires to modify some part of farmbot software sequences ? Or is it fully interchangeable with the valve ?

Thanks a lot in advance !

Hey @FabcityNancy_Farmbot

If you connect the pump to a unused pin, you will need to add “write pin” steps in your sequences to turn the pump on when needed. Connecting the pump parallel to the water valve might work without changing anything in the sequences.

Thank you very much for the tips !
Has anyone tried to supply FarmBot with water tank ? Some feedbacks to share ?

I do not know what is called in your country.
We are called “Toilet Bangbu.” Used in the toilet tank.

The water is connected … The water level is too low to replenish itself

I don’t know if this post is still being monitored, but we have set up our Farmbot on a rain barrel in Texas. We just wired the bilge pump into the existing farmduino cable and haven’t had any issues. Just make sure that the current draw is less than or equal to 1 amps. :slight_smile: It works like a charm!


We used an “in line” 12v irrigation pump and controlled it using an open pin. The pump we used was a Bayite pump with built-in pressure switch (shuts off when line is pressurized). We sequence to pump to be on at the start of a watering cycle and then open/close the solenoid for about 500 milisecond (1/2 second). It cost about $28 USD and was purchased from:

Hope this is helpful.

We are using a water tank and a pump with our Farmbot, and wanted to share here our experiences :

  • the bilge pump mentioned in the mods&addons section (350gph) was far from enough to move the water
  • we used a 2000gph pump, but the low pressure required almost 4 seconds of opening to get water at the output over the plants
  • that was fine for a time but I guess they are not supposed to be immersed all the time, as they are intended to remove the water from a boat hull as soon as it reach a level. The first stopped working after some month, inside the motor was corroded. We replaced it by an equivalent and after some month the same seems to have happened.
  • next time I intend to use a “high pressure” pump rated at 2A. After reading others searches and posts, that seems to be a reasonable max current draw for the connectors. Similar to the hotend of a 3D printer by the way. Like the pump mentioned just above by JWells, the water being fed “inline” the motor will be safe. This choice seems also much more adequate as we need more pressure than throughput to water the garden via the little tubing.

Maybe the mods&addons section should be edited to encourage people in using small high-pressure pumps instead of bilge pump ?


As a small follow-up to my previous message…
Before receiving the pump ordered I could try with a similar but 5A pump, 0.8mPa, that a friend had : it was a bit too much… But comparing to the previous 4 seconds opening to water plants, we used 500 to 700 milliseconds.
Today we installed the intended small 12V 2A high pressure pump (0,48mPa) and it is just fine :smiley:
(did not had to increase the opening time even with the slightly lower pressure).

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This looks great @Manu_Ledome !

Depending on how you hooked up the pump, you may be able to control output by using the CONTROL PERIPHERAL BLOCK with mode set to ANALOG- not sure if you tried that already, but I have had good results on unrelated DC motor applications.

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FYI it really depends on your local setup (municipal water line pressure or in your case pressure from the pump, length of vinyl tubing, the minor imperfections in each watering nozzle, it all adds up).

I’ve done some extensive testing with a measuring cup and using different timings opening the solenoid valve and figured that for a 50 millilitre shot, I need 150 milliseconds, but for a 100 millilitre shot it doesn’t mean 300 milliseconds (it’s 750 milliseconds), and for a 150 mL shot it’s not 450 ms (it’s 1500 ms).

I had to re-do this when I put tie-wraps around my vinyl tubing because every time the solenoid opened it would squirt some water and the UTM would flood.

All is to say that every FarmBot owner should figure out what works for their setup. I personally like being quite accurate in dosing my water. I live in a very dry area so rain rarely interferes, which allows me to water the garden very precisely (which helps with weed control).

It looks linear but near the beginning it bends down slightly. Also, as you can see, it really seems impossible to give less than 30 mL (even with opening the valve for 10 ms).

I suspect either it’s not possible to have millisecond control over the solenoid valve (but rather in “steps” of, say, 50 ms), or it’s the stored initial pressure in the line that pushes out more water in the first few milliseconds.

It’s probably a combination of both.


control output by using the CONTROL PERIPHERAL BLOCK with mode set to ANALOG

I forgot that but it could be fine tuned like that instead of ON/OFF indeed !

And @mdingena you are right, each setup should determine it’s own timings ! I mentioned the time I use more as a comparison with the previous bilge pump :slight_smile:

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Its interesting that the pump mentioned in mods&addons wasn’t sufficient. I used it and just posted about my project if you are interested:

Interesting to me that you ended up with a pump that was not submerged. I didn’t even consider that :slight_smile: Would have saved me a lot of time with epoxy. I need to look closer at this. Thank you for sharing.

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Do you mind also posting a link to the pump you used? One of the [surprising] things I’ve found is that sourcing parts can be extremely time consuming so its helpful to have a specific working example.

Thank you!

It was something similar to this one.
Note that we have an old Genesis in 12V.
For recent Farmbots in 24V this kind of pump seems less common.