How to run a 12V water pump with soil moisture sensor

The best way you can run a 12V dc motor with Arduino is to use L293D, which can supply from 5volts to 36volts. The below diagram is for a soil moisture sensor with a motor which could be 12V DC.
  • Pin 1,16 and 9 are for Arduino 5V only.
  • Pin 4,5,12 and 13 are for both Arduino and external power ground.
  • Pin 8 is for only external VCC.
  • Pin 3 and 6 are for motor.
  • Pin 2 and 7 are for controlling the motor which ever way you want.
Let's see the sketch now.

int motorf = 2;
int motorb = 7;

void setup() {
// initialize serial communication at 9600 bits per second:
pinMode(motorf, OUTPUT);
pinMode(motorb, OUTPUT);

void loop() {
// read the input on analog pin 1:
int sensorValue1 = analogRead(A1);

if (sensorValue1 >=600){
  digitalWrite(motorb, HIGH);
  else {
  digitalWrite(motorb, LOW);

int motorf = 2;  This is for motor to spin one way.
int motorb = 7;  And this is for motor to spin other way.

To control the spin of the motor you simply change "f" to "b" or "b" to "f" in [ digitalWrite(motorb, HIGH); ]

if (sensorValue1 >=600){ This means if moisture reading is above 600 then it will turn on the motor.

delay(500); This means it will get the reading every half a second, you can increase as you like.


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