there is a kit for the hardware you would want AMAZON KIT
these water pumps take about 3 minutes to pump a gallon of water. not so fast as to easily flood plants.
volume can be controlled by running time.
if you take a plastic box, size of a shoe box, put in your pumps and cut a hole for the tubing, you can put that on the table with your plants.
"pump head" is a technical term about how high a pump can pump (lift) water.
you can only pump water about half a meter over the water level of the pump. so you cannot put this on the floor and your plants on the table.
also, there is no way to stop the water from siphoning if the water container were over the height of the plants.
Overhead water storage would use a servo and a home made pinch valve.
The above link goes to a kit of the parts, you need to bring your Arduino, UNO, NANO or whatever that has at least 4 analog inputs (EPS8266 only has one)
Although the soil sensors are captive and will not wear out, I have had problem with accuracy and sensitivity.
dripping wet soil 'usually' has a reading of about 475, near bone dry the readings are about 495 and reading once a minute, I get readings that are not very steady.
reading each minute :
488
508
500
512
500
507
513
504
506
497
499
511
514
508
507
496
average for the last hour was 505
I average them over an hour and only use the hourly average .
These readings were from a plant container. When you push on the soil, your finger comes back with water.
I added water last night so the soil is very wet. I expected to see 475 not over 500....
I just water every 4 days, whether the plants need it or not.
The pots have open holes on the bottom. The excess spills out the bottom.
Since plants really do not care when they get water, I just use the system clock to water after it thinks 4 days has passed.
The photo is linked from Amazon for a 4 pump, 4 sensor project.
AA batteries are shown as the SEPARATE power source for the pumps.
we would advise that you use a phone charger and power both the relays and the pumps from one phone charger and then power the Arduino from the other. the alternate is to put in a large enough capacitor on the Arduino power supply to let it ride out the dip when the relays activate.
batteries will wear out in sort order.
The amazon kit has the parts you would want. the costs seems to be about $1 for a pump, $3 for each sensor and $4 for the relay board. free shipping. this is about the cost of the parts if bought on e-bay.
I use a 1k resistor on each output to the relay board to limit current to the relay board. Anything from 300 ohms to 1k should be fine.
