https://docs.arduino.cc/tutorials/plant-watering-kit/iot-smart-garden-setup-with-nanorp2040?_gl=1*758xvo*_ga*MTQ1NDA1MjgwMi4xNjg5NTI0MzY2*_ga_NEXN8H46L5*MTY5MjA3MDEwMi4yNS4xLjE2OTIwNzA0MTAuMC4wLjA.

Simplified Code( no Wifi or OLED):

// Simplified Irrigation Controller Program

#define pumpPin 6 //Output pin to turn on pump with transistor

int  moisture;

int  threshold= 300;

void setup() {

pinMode(pumpPin, OUTPUT);

moisture=0;

Serial.begin(9600);

}

void loop() {

    moisture = analogRead(A0);

   Serial.println(moisture);

  if (moisture < threshold){ // if water needed, pump runs for 10 seconds, then shuts off for 10 seconds.

   digitalWrite(pumpPin, HIGH);

   delay (10000);

   digitalWrite(pumpPin, LOW);

   delay(10000);

} else {

    digitalWrite(pumpPin, LOW);

  }

}

Wifi-connected Garden Monitor

Declarations- Includes needed libraries, sets up OLED Display:

Setup code runs once- sets up output pins, initializes Serial output, checks to see if display present:

Main Loop: Reads in sensor values from analog inputs, calculates temperature from  TMP 36 sensor reading:

Displays Sensor Values on OLED Display:

Code that turns pump on and off:

Thing Properties(automatically generated by Arduino IOT cloud):

"Secret" tab holds Wifi Name and Password:

Features: 

POWER:

Entire unit is powered using a 5V USB charger cube.  The 5V goes to Vin/GND on the top left, and also powers the water pump.

3V/GND output at bottom left powers a DHT 11 humidity/temp module(the blue thing), and a photocell for readings of daylight.

Both top and bottom ground rails are tied together.

Signals: 

The signal from the moisture sensor(yellow) goes to Pin D34(A0)

The signal from the DHT 11(green)  goes to Pin D32

The signal from the photocell(yellow) goes to Pin D35

The output to the pump(blue) is on Pin D33

One wire of the pump goes to +5V; the other pin goes to the collector of the TIP 120 transistor; when the transistor is turned on by the signal from the ESP32, the coilector is grounded, turning on the pump.

-------------------------------

Code: 

/*

  Sketch generated by the Arduino IoT Cloud Thing "Untitled"

  https://create.arduino.cc/cloud/things/b3bb7643-a022-4018-9309-cb4b16a98177

  Arduino IoT Cloud Variables description

  The following variables are automatically generated and updated when changes are made to the Thing

  int humidity;

  int moisture;

  int temperature;

  int light;

  bool pump;

  Variables which are marked as READ/WRITE in the Cloud Thing will also have functions

  which are called when their values are changed from the Dashboard.

  These functions are generated with the Thing and added at the end of this sketch.

*/

#include "thingProperties.h"

#include "DHT.h"

#define DHTPIN 32     // Digital pin connected to the DHT sensor

#define DHTTYPE DHT11   // DHT 22  (AM2302), AM2321

#define pumpPin 33.      //pin that drives the transistor

DHT dht(DHTPIN, DHTTYPE);

int threshold = 1200; // moisture threshold value to be determined by experiment

void setup() {

  // Initialize serial and wait for port to open:

  Serial.begin(9600);

  // This delay gives the chance to wait for a Serial Monitor without blocking if none is found

  delay(1500);

  dht.begin();

  // initialize pins

  pinMode(32, INPUT);  //input from DHT 22

  pinMode(33, OUTPUT); // output to turn on transistor

  pinMode(34, INPUT);  //input from moisture sensor

  pinMode(35, INPUT);  //input from light sensor

  // Defined in thingProperties.h

  initProperties();

  // Connect to Arduino IoT Cloud

  ArduinoCloud.begin(ArduinoIoTPreferredConnection);

  /*

     The following function allows you to obtain more information

     related to the state of network and IoT Cloud connection and errors

     the higher number the more granular information you’ll get.

     The default is 0 (only errors).

     Maximum is 4

  */

  setDebugMessageLevel(2);

  ArduinoCloud.printDebugInfo();

}

void loop() {

  ArduinoCloud.update();

  // Your code here

  moisture = analogRead(34);

  light = analogRead(35);   //optional photoresistor

  humidity = dht.readHumidity();

  temperature = dht.readTemperature();

  Serial.println(moisture);

  Serial.println(humidity);

  Serial.println(temperature);

  Serial.println(light);

  delay(2000);

  if (moisture < threshold)

  {

    digitalWrite(pumpPin, HIGH);

    delay(5000);

    digitalWrite(pumpPin, LOW);

    delay(10000);

  } else {

    digitalWrite(pumpPin, LOW);

  }

}

  /*

    Since Pump is READ_WRITE variable, onPumpChange() is

    executed every time a new value is received from IoT Cloud.

    // Add your code here to act upon Pump change

  */

  void onPumpChange()  {

    if (pump) {

      digitalWrite(pumpPin, HIGH);

    }

    else {

      digitalWrite(pumpPin, LOW);

    }

  }

//-------------- Properties Tab

// Code generated by Arduino IoT Cloud, DO NOT EDIT.

#include <ArduinoIoTCloud.h>

#include <Arduino_ConnectionHandler.h>

const char DEVICE_LOGIN_NAME[]  = "e294cc78-3001-453f-a8b2-697c51a3b140";

const char SSID[]               = SECRET_SSID;    // Network SSID (name)

const char PASS[]               = SECRET_OPTIONAL_PASS;    // Network password (use for WPA, or use as key for WEP)

const char DEVICE_KEY[]  = SECRET_DEVICE_KEY;    // Secret device password

void onPumpChange();

int humidity;

int light;

int moisture;

int temperature;

bool pump;

void initProperties(){

  ArduinoCloud.setBoardId(DEVICE_LOGIN_NAME);

  ArduinoCloud.setSecretDeviceKey(DEVICE_KEY);

  ArduinoCloud.addProperty(humidity, READ, 15 * SECONDS, NULL);

  ArduinoCloud.addProperty(light, READ, 15 * SECONDS, NULL);

  ArduinoCloud.addProperty(moisture, READ, 20 * SECONDS, NULL);

  ArduinoCloud.addProperty(temperature, READ, 15 * SECONDS, NULL);

  ArduinoCloud.addProperty(pump, READWRITE, ON_CHANGE, onPumpChange);

}

WiFiConnectionHandler ArduinoIoTPreferredConnection(SSID, PASS);