Arduino Nano ESP32 - Secure Your Belongings: Detect Theft and Send Email Alerts

In this guide, we will teach you how to keep your items safe using an Arduino Nano ESP32 and a force sensor. We will cover the steps to set up a system that sends you an email if someone tries to move your belongings. You will learn how to prepare the Arduino Nano ESP32, connect the force node, and set it up to email you through Gmail. We will provide detailed instructions and show you how this system can be useful.

Arduino Nano ESP32 Theft detection Email Notification

Hardware Preparation

1×Arduino Nano ESP32
1×USB Cable Type-C
1×Force Sensor
1×10 kΩ resistor
1×Jumper Wires
1×(Optional) DC Power Jack
1×(Recommended) Screw Terminal Adapter for Arduino Nano

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 the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you. We appreciate your support.

Overview of Force Sensor and Gmail

We provide detailed guides on Force Sensors and Gmail. Each tutorial gives you step-by-step instructions on setting up the hardware, understanding how it functions, and connecting wires to Arduino Nano ESP32, including how to code for Arduino Nano ESP32. For more details, please visit these links:

How the theft detection system work

The force sensor measures the weight of an item placed on it. When you put your item on the sensor, the Arduino Nano ESP32 records the weight. If the item is taken away, the weight will change. The Arduino Nano ESP32 detects this change and sends you an email to inform you that your item has been moved.

Wiring Diagram between Force Sensor and Arduino Nano ESP32

The wiring diagram between Arduino Nano ESP32 and Force Sensor

This image is created using Fritzing. Click to enlarge image

Arduino Nano ESP32 Code

/* * This Arduino Nano ESP32 code was developed by * * This Arduino Nano ESP32 code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * */ #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 "" // CHANGE IT #define SENDER_PASSWORD "xxxx xxxx xxxx xxxx" // CHANGE IT to your Google App password #define RECIPIENT_EMAIL "" // CHANGE IT #define SMTP_HOST "" #define SMTP_PORT 587 #define FORCE_SENSOR_PIN A0 // The Arduino Nano ESP32 pin A0 are connected to the FSR with 10K pulldown resistor #define THRESHOLD 100 // may need to callibrate this value 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(DOOR_SENSOR_PIN, INPUT_PULLUP); // set ESP32 pin to input pull-up mode door_state = digitalRead(DOOR_SENSOR_PIN); // read state } void loop() { int forceValue = analogRead(FORCE_SENSOR_PIN); if (forceValue < THRESHOLD) { Serial.println("Alert! Someone has stolen your stuff!"); String subject = "Email Notification from ESP32"; String textMsg = "This is an email sent from ESP32.\n"; textMsg += "Alert! Someone has stolen your stuff!"; 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; = SENDER_EMAIL; config.login.password = SENDER_PASSWORD; config.login.user_domain = F(""); config.time.ntp_server = F(","); config.time.gmt_offset = 3; config.time.day_light_offset = 0; // declare the message class SMTP_Message message; // set the message headers = F("ESP32"); = 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: <>")); // 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(; // 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(); } }

Detailed Instructions

To get started with Arduino Nano ESP32, follow these steps:

  • If you are new to Arduino Nano ESP32, refer to the tutorial on how to set up the environment for Arduino Nano ESP32 in the Arduino IDE.
  • Connect the Arduino Nano ESP32 board to the force sensor according to the provided diagram.
  • Connect the Arduino Nano ESP32 board to your computer using a USB cable.
  • Open the Arduino IDE on your computer.
  • Select the Arduino Nano ESP32 board and its corresponding COM port.
  • Place your items on the force sensor.
  • Open the Library Manager by clicking Library Manager icon on the left side of the Arduino IDE.
  • Search for ESP Mail Client and choose the library by Mobizt.
  • Click the Install button to add the ESP Mail Client library.
Arduino Nano ESP32 ESP Mail Client library
  • Copy the code and open it using the Arduino IDE.
  • Enter your WiFi details (name and password) in the code by changing WIFI_SSID and WIFI_PASSWORD.
  • Enter the email and password of the person sending the email in the code by changing SENDER_EMAIL and SENDER_PASSWORD.
  • Enter the email address of the person receiving the email in the code by changing RECIPIENT_EMAIL. This email can be the same as the sender's email.


  • The sender's email address needs to be a Gmail account.
  • Use the App password you got earlier as the sender's password.
  • Any email provider can be used for the recipient's email address.
  • Press the Upload button in the Arduino IDE to transfer code to the Arduino Nano ESP32.
  • Open the Serial Monitor.
  • Take items off the force sensor.
  • Check the results on the Serial Monitor.
Alert! Someone has stolen your stuff! #### 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: Subject: Email Notification from Arduino Nano ESP32 ----------------
Autoscroll Show timestamp
Clear output
9600 baud  
  • Check the email inbox of the person you're sending to. They will get an email similar to this:
Arduino Nano ESP32 theft detection email

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