In this instructable I will show you an automated watering system for your plants.
The whole thing is pretty easy but useful if you have some extra job to do next to the plants.
Actually all the hardware needed costs less than $10(excluding the pump, pipes and sprayers).
Here`s the hardware needed:
1. Arduino Pro Mini (ATmega328P, 5V, 16M) - http://www.ebay.com/itm/131278764259?_trksid=p2057... - $1.97
2. Soil Hygrometer - http://www.ebay.com/itm/Soil-Hygrometer-Moisture-W... - $0.99
3. 24V-380V SSR-25DA 25A 3-32V DC-AC Solid State Relay - http://www.ebay.com/itm/272032238148?_trksid=p2057... - $3.10
4. Input AC 110-240V Output DC 9V 1A Switching Power Supply Adapter - http://www.ebay.com/itm/Input-AC-110-240V-Output-D... - $2.60 (you can use any power supply with output 9V/1A you have to save more $)
5. Any monophase water pump you like and you can afford
6. Pipes & Joints (as much as you need)
7. Sprayers (as much as you need)
8. Soldering Iron
9. Soldering Wire
10. Skills in soldering and plumbing/good friends with those skills/enough money to pay for all that :D
Step 1: Some Fast Cuts
Arduino Pro Mini -> Mini
Solid State Relay -> SSR
AC Power Adapter -> AC
Soil Hygrometer -> Hygro
Integrated Circuit Voltage Pin -> VCC(+/plus)
Ground -> GND(-/minus)
Analog Pin 0(zero) -> A0
Digital Pin 2 -> D2
Amps -> A (ex. 25A)
N.B. !!! /!\ DON`T TRY THIS INSTRUCTABLE IF YOU HAVE NO EXPERIENCE WITH VOLTAGES HIGHER THAN 12V !!! OTHER WAY YOU ARE RISKING OF HAVING ELECTRIC SHOCK ON YOU, ANIMALS, OTHER PEOPLE WHICH CAN CAUSE SERIOUS INJURIES OR EVEN DEATH !!! /!\
Step 2: Wiring All Together
First of all we NEED to program our Arduino Pro Mini. As not having any kind of USB port we have to use Arduino UNO rev3 as a programer. Personally I did it following this Instructable - https://www.instructables.com/id/Program-Arduino-Pro-Mini-Using-Arduino-Uno/
Than we have to cut the end of the AC Power Adapter. With a multimeter we will find which one is VCC(+) and which one is GND(-). We will solder them VCC(AC) to RAW(Mini) and GND(AC) to GND(Mini(next to RAW)). Now we have supplied our Arduino Pro Mini with power. N.B. !!! /!\ DO NOT CONNECT AC POWER ADAPTER TO VCC ON THE ARDUINO PRO MINI UNLESS THE ADAPTER IS EXACTLY 5V/1A OR YOU ARE RISKING OF BRICKING YOUR MINI(DON`T COUNT ON THE OVERPOWER PROTECTIONS - THEY HOLD, BUT NOT FOREVER!!!). CONNECT THE ADAPTER VCC(+) EXACTLY ON THE RAW. RAW SUPPORTS 6~20V!!! /!\
Now we have to connect the Soil Hygrometer to the Arduino Pro Mini. VCC(Hygro) to VCC(Mini), GND(Hygro) to GND(Mini) and A0(Hygro) to A0(Mini).
Now we need to connect the Arduino Pro Mini and the Solid State Relay but first few words about SSR. In this case we are using Solid State Relay 25A. NOT the 10A. The 10A relay is good for lights, hairdryers, mixers and etc. Something strong like a water pump needs 25A. If you are TOO MUCH scared that it`s not enough you can use a 40A SSR, but normally a socket is 20A so 25A relay is MORE THAN ENOUGH.
Now connect GND(Mini) to one of the ports of the SSR and D2 to the other port of the SSR.(Just in case to remind that those two are going on the side where is written 3~32VDC on the SSR).
Last thing on the wire connections is the SSR to the pump. Using a normal cable for a socket extension connect the GND directly to the GND of the pump. The VCC needs one extra cable. The extension VCC connect to one of the ports of the SRR. The extra cable to the other port of the SSR and to the VCC of the water pump.(Just in second case to remind that those two are going on the side where is written 24~380VAC on the SSR).
N.B. /!\ REMEMBER ALWAYS TO CUT THE VCC WITH A RELAY, NOT THE GND!!! /!\ OTHER WAY YOU ARE RISKING OF HAVING ELECTRIC SHOCK WHICH CAN CAUSE SERIOUS INJURIES OR EVEN DEATH !!! /!\
P.S. Use a small cross screw driver to adjust the sensitivity of your soil hygrometer.
P.P.S. It`s always better not to use a socket for a water pump. Connect it directly to the electric grid using a circuit breaker 25A - http://www.ebay.com/itm/DZ47-60-C25-AC230-400V-1P-25A-Rated-Current-1-Pole-Miniature-Circuit-Breaker-/350690168788?hash=item51a6c34fd4:g:LBsAAMXQhpdRzpcA - $3.56. Like this you will be sure that even if something goes wrong/short the only thing that will switch off is your circuit breaker and your water pump.
Sorry for my bad english and I hope that this one will help somebody to make his/her life better like mine.
Have fun and don`t stop dreaming because the only limit is your dreams !