This is an old revision of the document!
Smart Garden
Dinca Laura-Aida - SSA
Project Description
Smart Garden project aims to be a plant environment monitoring system. Thanks to a temperature and humidity sensor, we have the data on the basis of which we can implement a logic for opening the irrigation system when needed. Being a proof of concept implementation, it has not yet been used in a real garden and the condition for opening the valve is chosen for testing purposes.
Hardware
Components:
- NodeMCU 32S
- Raspberry pi 4
- DHT22 - temperature and humidity sensor
- Solenoid valve - 12V, normally closed
- H-Bridge - model L298N, 12V
- Resistor 10kOhm
- Power supply adapter - 12V
- Breadboard
- Connection wires
Electric circuit
Software
Raspberry Pi server
This part is for creating the database and for defining its elements; in this case, an id and two integers, temperature and humidity for the values read from the sensor.
import sqlite3 import os database_path = "./database.db" conn = sqlite3.connect(database_path) cursor = conn.cursor() cursor.execute(""" CREATE TABLE IF NOT EXISTS sensorData ( id INTEGER PRIMARY KEY, temperature INTEGER, humidity INTEGER ) """) conn.commit() conn.close()
For displaying the latest data when making a GET request, we include the following:
<!DOCTYPE html>
<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0, user-scalable=no\">
<title>ESP32 Weather Report</title>
<style>html { font-family: Helvetica; display: inline-block; margin: 0px auto; text-align: center;}
body{margin-top: 50px;} h1 {color: #444444;margin: 50px auto 30px;}
p {font-size: 24px;color: #444444;margin-bottom: 10px;}
</style>
</head>
<body>
<div id=\"webpage\">
<h1>ESP32 Weather Report</h1>
<p>Temperature: {{temperature}}° C</p>
<p>Humidity: {{humidity}} %</p>
</div>
</body>
</html>
from flask import Flask, send_file, request, render_template import sqlite3 app = Flask(__name__) database_path = "./database.db" @app.route('/insert_sensor_data', methods=['POST']) def insert_sensor_data(): # Connect to the database conn = sqlite3.connect(database_path) cursor = conn.cursor() data = request.get_json(); humidity = data['humidity'] temperature = data['temperature'] # Save the data in the database cursor.execute("INSERT INTO sensorData (temperature, humidity) VALUES (?, ?)", (temperature, humidity)) # Commit the changes and close the database connection conn.commit() conn.close() return "Sensor data uploaded" @app.route('/latestData') def latest_data(): # Connect to the database conn = sqlite3.connect(database_path) cursor = conn.cursor() # Retrieve the image from the database based on the image_id cursor.execute("SELECT temperature, humidity FROM sensorData WHERE id = (SELECT MAX(id) from sensorData)") result = cursor.fetchone() # Save the data to a temporary file temperature = result[0] humidity = result[1] # Close the database connection conn.close() # Send the data file in the response return render_template('./index.html',temperature=temperature, humidity=humidity) if __name__ == '__main__': app.run(host='0.0.0.0', port=5000)
ESP32 environment
Initializing the pin connections and DHT sensor, including the necessary libraries and the variables for connecting to the network (both ESP32 and Raspberry pi be connected to the same WI-FI):
#include <WiFi.h> #include <HTTPClient.h> #include <WebServer.h> #include "DHT.h" #define DHTTYPE DHT22 #define RELAY_PIN 16 const char* ssid = ""; // Enter SSID here const char* password = ""; //Enter Password here // DHT Sensor uint8_t DHTPin = 4; // Initialize DHT sensor. DHT dht(DHTPin, DHTTYPE); float temperature; float humidity;
void setup() { Serial.begin(115200); delay(100); pinMode(DHTPin, INPUT); dht.begin(); pinMode(RELAY_PIN, OUTPUT); //connect to your local wi-fi network WiFi.begin(ssid, password); //check wi-fi is connected to wi-fi network while (WiFi.status() != WL_CONNECTED) { delay(1000); Serial.print("."); } Serial.println(""); Serial.println("WiFi connected..!"); Serial.print("Got IP: "); Serial.println(WiFi.localIP()); }
In the loop() function, we read the values and send them using the created http client as json:
HTTPClient http; // Prepare the data that will be send temperature = dht.readTemperature(); humidity = dht.readHumidity(); String data = "{\"humidity\":" + String(humidity) + ",\"temperature\":" + String(temperature) + "}"; // Send a POST request with JSON data http.begin("http://192.168.1.104:5000/insert_sensor_data"); http.addHeader("Content-Type", "application/json"); int httpResponseCode = http.POST(data); // Check the response code if (httpResponseCode > 0) { String response = http.getString(); Serial.println(httpResponseCode); Serial.println(response); } else { Serial.print("Error sending request: "); Serial.println(httpResponseCode); }
The condition for opening the valve is defined below:
//condition for opening the valve if ((int(temperature) > 35) && (int(humidity) <60)) { digitalWrite(RELAY_PIN, HIGH); // open valve 20 seconds delay(20000); digitalWrite(RELAY_PIN, LOW); // close valve }
