ESP32 - Water Leak Email Notification

In this tutorial, we are going to learn how to use the ESP32 to detect water leaks and send real-time notifications via email. This step-by-step tutorial covers sensor setup, code examples, and integration with email services, ensuring your home or office is protected from potential water damage. Perfect for DIY enthusiasts and smart home developers looking to enhance their water leak detection systems.

ESP32 Water Leak Email Notification

Hardware Used In This Tutorial

1×ESP-WROOM-32 Dev Module
1×USB Cable Type-C
1×Water Leak Detector
1×Breadboard
1×Jumper Wires
1×(Optional) DC Power Jack
1×(Recommended) Screw Terminal Expansion Board for ESP32

Or you can buy the following sensor kits:

1×DIYables Sensor Kit (30 sensors/displays)
1×DIYables Sensor Kit (18 sensors/displays)
Disclosure: some of these links are affiliate links. We may earn a commission on your purchase at no extra cost to you. We appreciate it.

Introduction to Water Sensor and Gmail

We have specific tutorials about Water Sensor and Gmail. Each tutorial contains detailed information and step-by-step instructions about hardware pinout, working principle, wiring connection to ESP32, ESP32 code... Learn more about them at the following links:

Wiring Diagram between Water Sensor and ESP32

ESP32 Water Sensor Wiring Diagram

This image is created using Fritzing. Click to enlarge image

If you're unfamiliar with how to supply power to the ESP32 and other components, you can find guidance in the following tutorial: How to Power ESP32.

ESP32 Code

/* * This ESP32 code is created by esp32io.com * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-water-leak-email-notification */ #include <WiFi.h> #include <ESP_Mail_Client.h> #define WIFI_SSID "YOUR_WIFI_SSID" // CHANGE IT #define WIFI_PASSWORD "YOUR_WIFI_PASSWORD" // CHANGE IT // the sender email credentials #define SENDER_EMAIL "xxxxxx@gmail.com" // CHANGE IT #define SENDER_PASSWORD "xxxx xxxx xxxx xxxx" // CHANGE IT to your Google App password #define RECIPIENT_EMAIL "xxxxxx@gmail.com" // CHANGE IT #define SMTP_HOST "smtp.gmail.com" #define SMTP_PORT 587 #define WATER_SENSOR_PIN 19 // ESP32 pin GPIO19 connected to water sensor's pin int water_state; // current state of water sensor int prev_water_state; // previous state of water sensor SMTPSession smtp; void setup() { Serial.begin(9600); WiFi.begin(WIFI_SSID, WIFI_PASSWORD); Serial.print("Connecting to Wi-Fi"); while (WiFi.status() != WL_CONNECTED) { Serial.print("."); delay(300); } Serial.println(); Serial.print("Connected with IP: "); Serial.println(WiFi.localIP()); Serial.println(); pinMode(WATER_SENSOR_PIN, INPUT_PULLUP); // set ESP32 pin to input pull-up mode water_state = digitalRead(WATER_SENSOR_PIN); // read state } void loop() { prev_water_state = water_state; // save the last state water_state = digitalRead(WATER_SENSOR_PIN); // read new state if (prev_water_state == HIGH && water_state == LOW) { Serial.println("Water leakage is detected!"); String subject = "Email Notification from ESP32"; String textMsg = "This is an email sent from ESP32.\n"; textMsg += "Water leakage is detected"; gmail_send(subject, textMsg); } } void gmail_send(String subject, String textMsg) { // set the network reconnection option MailClient.networkReconnect(true); smtp.debug(1); smtp.callback(smtpCallback); Session_Config config; // set the session config config.server.host_name = SMTP_HOST; config.server.port = SMTP_PORT; config.login.email = SENDER_EMAIL; config.login.password = SENDER_PASSWORD; config.login.user_domain = F("127.0.0.1"); config.time.ntp_server = F("pool.ntp.org,time.nist.gov"); config.time.gmt_offset = 3; config.time.day_light_offset = 0; // declare the message class SMTP_Message message; // set the message headers message.sender.name = F("ESP32"); message.sender.email = SENDER_EMAIL; message.subject = subject; message.addRecipient(F("To Whom It May Concern"), RECIPIENT_EMAIL); message.text.content = textMsg; message.text.transfer_encoding = "base64"; message.text.charSet = F("utf-8"); message.priority = esp_mail_smtp_priority::esp_mail_smtp_priority_low; // set the custom message header message.addHeader(F("Message-ID: <abcde.fghij@gmail.com>")); // connect to the server if (!smtp.connect(&config)) { Serial.printf("Connection error, Status Code: %d, Error Code: %d, Reason: %s\n", smtp.statusCode(), smtp.errorCode(), smtp.errorReason().c_str()); return; } if (!smtp.isLoggedIn()) { Serial.println("Not yet logged in."); } else { if (smtp.isAuthenticated()) Serial.println("Successfully logged in."); else Serial.println("Connected with no Auth."); } // start sending Email and close the session if (!MailClient.sendMail(&smtp, &message)) Serial.printf("Error, Status Code: %d, Error Code: %d, Reason: %s\n", smtp.statusCode(), smtp.errorCode(), smtp.errorReason().c_str()); } // callback function to get the Email sending status void smtpCallback(SMTP_Status status) { // print the current status Serial.println(status.info()); // print the sending result if (status.success()) { Serial.println("----------------"); Serial.printf("Email sent success: %d\n", status.completedCount()); Serial.printf("Email sent failed: %d\n", status.failedCount()); Serial.println("----------------\n"); for (size_t i = 0; i < smtp.sendingResult.size(); i++) { // get the result item SMTP_Result result = smtp.sendingResult.getItem(i); Serial.printf("Message No: %d\n", i + 1); Serial.printf("Status: %s\n", result.completed ? "success" : "failed"); Serial.printf("Date/Time: %s\n", MailClient.Time.getDateTimeString(result.timestamp, "%B %d, %Y %H:%M:%S").c_str()); Serial.printf("Recipient: %s\n", result.recipients.c_str()); Serial.printf("Subject: %s\n", result.subject.c_str()); } Serial.println("----------------\n"); // free the memory smtp.sendingResult.clear(); } }

Quick Instructions

  • If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
  • Install the water sensor on the place that can encounter with water leak
  • Connect the ESP32 board to the water sensor
  • Connect the ESP32 board to your PC via a micro USB cable
  • Open Arduino IDE on your PC.
  • Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
  • Open the Library Manager by clicking on the Library Manager icon on the left navigation bar of Arduino IDE.
  • Search ESP Mail Client, then find the ESP Mail Client created by Mobizt.
  • Click Install button to install ESP Mail Client library.
ESP32 ESP Mail Client library
  • Copy the above code and open with Arduino IDE
  • Change the WiFi information (SSID and password) in the code to yours by changing two contanst WIFI_SSID and WIFI_PASSWORD
  • Change the sender email and password in the code to yours by changing two contanst SENDER_EMAIL and SENDER_PASSWORD
  • Change the recipient email in the code to yours by changing two contanst RECIPIENT_EMAIL. recipient email can be the same as sender

※ NOTE THAT:

  • Sender email MUST be Gmail
  • Sender password is the App passwords you got from previous step
  • Recipient email can be any type of email
  • Click Upload button on Arduino IDE to upload code to ESP32
  • Open the Serial Monitor
  • Pour some water to the water sensor
  • Check out the result on Serial Monitor.
COM6
Send
Water leakage is detected #### Email sent successfully > C: Email sent successfully ---------------- Message sent success: 1 Message sent failed: 0 ---------------- Message No: 1 Status: success Date/Time: May 27, 2024 04:42:50 Recipient: xxxxxx@gmail.com Subject: Email Notification from ESP32 ----------------
Autoscroll Show timestamp
Clear output
9600 baud  
Newline  
  • Check your recipient email box. You will get an email as below:
ESP32 water sensor email

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