Designing an IoT-Based Home Security System

Study Case Designing an IoT-Based Home Security System Using NodeMCU ESP8266 Michael Kurniawan (2018123456) University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45221, United States kurniaml@mail.uc.edu Abstract The Internet of Things (IoT) is a field of research that has great potential to improve quality of life through the use of smart sensors and devices that are connected to each other via the internet. One important application of IoT is in home security systems. The high rate of residential burglary and other potential hazards such as fire are the main reasons for the need for a more modern security system. Generally, homes still use conventional systems that are relatively easy to break into. To overcome this, a security system based on NodeMCU ESP8266, RFID, PIR sensor, DHT11, and Blynk was designed. The prototype developed is a miniature house that can lock doors, detect the presence of someone around the house, and read room temperature. If the temperature rises above 32°C, the system will provide a warning via LCD, buzzer, LED, and send a notification directly to the homeowner's smartphone. Keywords: RFID, NodeMCU ESP8266, DHT11, PIR, Blynk. INTRODUCTION The Internet of Things (IoT) is a field of research with great potential to improve quality of life through the use of smart sensors and devices that interact with each other via the internet [1]. IoT allows users to control and optimize electronic devices and household appliances that are connected online [2]. In the modern era, human dependence on the internet makes IoT highly relevant, not only for data transfer but also for automation and monitoring systems. One of the supporting technologies for IoT is WiFi (Wireless Fidelity), which is found in almost all electronic devices today. NodeMCU is a WiFi-based microcontroller MICHAEL KURNIAWAN 1 Study Case module that is widely used in various electronics projects due to its ease of use [3]. Homes are not only places to live and rest, but also places to store valuables [4]. However, homes are often left empty, for example when the owners are at work or on vacation. This increases the risk of theft. According to data from the Federal Bureau of Investigation (FBI) Uniform Crime Reports in 2015, there were approximately 1.6 million cases of residential burglary in the United States. For every 100,000 people, approximately 140 people are at risk of becoming victims of crime. This figure causes concern among the public, especially when leaving their homes empty [5]. Conventional home security systems are considered inadequate. For example, mechanical keys are still easy to duplicate, while CCTV only records without providing real-time alerts [6]. In addition to theft, fire is also a serious threat that can destroy the entire contents of a home, so an ideal security system must be able to anticipate both risks [7]. Technological developments have enabled the implementation of more sophisticated security systems, such as smart door locks that no longer require physical keys. To address these needs, this study designed an IoT-based home security system with a combination of sensors capable of: • securing doors using RFID and solenoid door locks, • detecting movement with PIR sensors, • and monitoring room temperature using DHT11 sensors. This system is integrated with the Blynk application on smartphones to monitor home conditions remotely. Previous research has shown the effectiveness of using RFID, push buttons, NodeMCU ESP32, magnetic sensors, and relays for home security systems. The test results show that the solenoid door lock works well to open and close doors automatically through the Blynk application [5]. Another study in 2022 also proved the success of using RFID and touch sensors to automatically unlock doors for 5 seconds before they lock again [9]. Referring to previous studies, this project aims to create a home security system that not only prevents theft but also detects potential fires. In its implementation, RFID and solenoid door locks secure door access, PIR sensors detect movement around windows, and DHT11 monitors room temperature. MICHAEL KURNIAWAN 2 Study Case Referring to temperature comfort standards in humid climates such as parts of the southern United States, normal temperatures range from 75°F–89°F (24°C–32°C). If the temperature exceeds 32°C (± 89.6°F), the system will provide a warning via a buzzer, LED, LCD, and smartphone notification via the Blynk application [10]. RESEARCH METHOD This study consists of three main stages, namely: 1. System Design 2. Prototype Testing 3. Security System Implementation OVERVIEW The application of IoT technology in home security aims to improve property protection and provide remote monitoring capabilities through smartphone applications. This system allows residents to access security information even when they are away from home. As shown in Figure 1, input is obtained from RFID, PIR, and DHT11 sensors. This data is then processed by NodeMCU ESP8266 as the main microcontroller. Output is generated through LEDs, buzzers, and LCDs as information media, as well as solenoid door locks as door security actuators. All data is also sent to the Blynk application on the homeowner's smartphone for real-time notifications. Figure 1. Overview Diagram of the IoT-Based Home Security System MICHAEL KURNIAWAN 3 Study Case DEVICE DESIGN The design stage was carried out by creating a block diagram consisting of three main blocks: input, process, and output. • Input: RFID, DHT11, and PIR sensors. • Process: NodeMCU ESP8266 programmed through Arduino IDE. • Output: LCD, relay module, solenoid door lock, buzzer, and LED. Pin configuration: • RFID uses pins D3–D8. • DHT11 uses the RX pin. • PIR uses pin D0. • Relays and other outputs are controlled through additional digital pins using the PCF8574 module. Figure 2. System Block Diagram The system is designed so that RFID can be used both inside and outside the house. If the ID card is valid, the door will open. The PIR sensor detects movement around the window, while the DHT11 monitors the room temperature. If the temperature is ≥ 33°C (± 91.4°F), the system triggers an alarm in the form of an LED and buzzer. MICHAEL KURNIAWAN 4 Study Case Figure 3. System Flow Diagram The flowchart in Figure 3 shows the system's operation process: 1. The device is checked to see if it is connected to the power adapter. 2. NodeMCU checks the internet connection. 3. The program initializes all sensors. 4. RFID reads the ID card → if valid, the solenoid opens and access is granted; if invalid, access is denied. 5. DHT11 monitors the temperature → if it exceeds 33°C, a warning is sent to the LCD, buzzer, LED, and Blynk application. 6. PIR sensor detects movement near the window → if detected, the system provides real-time alerts via hardware and the Blynk application. MICHAEL KURNIAWAN 5 Study Case Figure 4. Overall System Circuit RESULTS AND DISCUSSION RFID RC522 Test Results The RFID RC522 was tested with registered and unregistered ID cards. The test distance varied between 0.5 cm, 1 cm, 2 cm, and 3 cm with the card positioned horizontally, vertically, and at an angle. Table 1. RFID Test Results with Registered ID Cards MICHAEL KURNIAWAN 6 Study Case Table 2. RFID Test Results with Unregistered ID Cards DHT11 Sensor Test Results The DHT11 was tested at temperatures ranging from 24°C to 33°C (75.2°F– 91.4°F). • Temperature 24–32°C → still within the normal range. • Temperature ≥ 33°C → considered abnormal, the system triggers an alert via buzzer, LED, and application notification. Table 3. Thermal Comfort Standards Table 4. Temperature Measurement Results with DHT11 PIR Sensor Test Results The PIR sensor was tested at distances of 1–5 cm, 6–10 cm, and 11–20 cm to detect the presence of objects near the window. MICHAEL KURNIAWAN 7 Study Case Table 5. Object Detection Results by PIR Sensor Overall Device Test Results The prototype system was made to resemble a miniature house with a door, window, RFID near the door, and PIR sensor above the window. LEDs, buzzers, and LCDs were placed at the front. Figure 5. Appearance of the Home Security System Prototype Testing was carried out with 10 trials of tapping registered ID cards, and the results showed a high success rate. Table 6. RFID Test Results with 10 Trials MICHAEL KURNIAWAN 8 Study Case Figure 6. Display of Access Notification via RFID The DHT11 sensor also successfully read the temperature conditions: • At normal temperatures, only the information was displayed. • At temperatures ≥ 33°C, the system provided LED and buzzer warnings and Blynk notifications. Table 7. DHT11 Sensor Test Results Figure 7. Notification Display from the DHT11 Sensor The PIR sensor demonstrated the ability to detect movement according to the set parameters. If an object is within a distance of 1–5 cm, the system immediately gives a warning. Table 8. PIR Sensor Test Results MICHAEL KURNIAWAN 9 Study Case Figure 8. Notification Display from the PIR Sensor CONCLUSION Based on the test results, all components—from RFID, PIR, to DHT11—functioned as expected. RFID was able to validate cards accurately, PIR detected movement near the window, and DHT11 successfully monitored room temperature and triggered an alarm when it exceeded the threshold. All information can be monitored in real-time through the Blynk app. Although the system works well, there are limitations, namely: • The device must always be connected to the internet. • PIR detection is still limited. Further development could include: • Integration of a smart camera to support visual detection. • Addition of body or animal temperature sensors to make the system more precise. MICHAEL KURNIAWAN 10 Study Case REFERENCE MICHAEL KURNIAWAN 11