IoT Plant Monitor

IoT Plant Monitor

Image: CSIRO ScienceImage 3719 CSIROs Fleck wireless sensor network technology.jpg by Stephan Brosnan, CSIRO via Wikimedia Commons, CC BY 3.0

How It Works

• A capacitive or resistive soil moisture sensor reads how dry the soil is; an LDR or light sensor and a temperature sensor round out the environmental picture.
• The Wi-Fi module (ESP8266/ESP32) pushes these readings to a cloud IoT platform (Blynk or ThingSpeak) at a set interval.
• When soil moisture drops below a set threshold, the system pushes an alert to the grower's phone/dashboard rather than requiring a manual daily check.
• Historical readings logged on the cloud platform let the grower see trends over days or weeks, not just the current moment.

Components

ESP8266 or ESP32
Capacitive soil moisture sensor
LDR or light sensor
DHT11/DHT22 temperature sensor
IoT platform (Blynk / ThingSpeak)
Battery pack or solar supply for outdoor use

Applications

• Houseplant and indoor garden care
• Small-scale precision agriculture monitoring
• Greenhouse condition tracking

Advantages

• Catches under-watering before visible wilting occurs
• Remote monitoring means no need to be physically present to check plant health
• Historical logging reveals watering patterns a single check can't show

Sample Code — Soil Moisture Threshold Alert

// Simplified soil moisture -> cloud alert - ESP8266/ESP32
#include 
int moisturePin = A0;
int dryThreshold = 400; // calibrate to sensor's dry-soil reading

void setup() {
  Serial.begin(9600);
  WiFi.begin("SSID", "PASSWORD");
}

void loop() {
  int moisture = analogRead(moisturePin);
  Serial.println(moisture);

  if (moisture > dryThreshold) {
    // pushToCloud("Soil is dry - water needed"); // Blynk/ThingSpeak call
    Serial.println("ALERT: soil dry, water needed");
  }
  delay(60000); // check every minute
}

Related Research

• IoT Based Smart Irrigation System Using Soil Moisture Sensor and ESP8266 NodeMCU — ResearchGate