A project involves creating a device that uses an ESP32 microcontroller to read RFID tags, allowing for wireless identification and access control applications.
The project includes source code for an RFID Reader with the following requirements:
- Read RFID Card: The ESP32 must be able to read data from RFID cards using an attached RFID reader module, capturing the unique identifier (UID) and other stored information from the card.
- Display Card Info on OLED Screen: Upon successfully reading an RFID card, the ESP32 should display the card's information, such as the UID and any additional data, on an OLED screen connected to the microcontroller.
- Activate Buzzer and LED on RFID Tap: When an RFID card is tapped and read, the ESP32 should trigger a buzzer and light up an LED to provide audible and visual feedback, indicating a successful read operation.
- Debouncing: Introducing a debounce time interval during which repeated taps of the same card are ignored to prevent duplicate reads.
- State Management: Maintaining a record of recently read card UIDs and ensuring that any repeated taps within a predefined time window are disregarded.
Link video demo: Link demo
- RFID CARDs
- ESP32 Module
- Programming Cable
- RFID-RC522
- OLED SSD1306
- Led
- Buzzer
- ArduinoIDE: For programming the device
- Altium: For designing schematic
- ESP32 Microcontroller x1
- LED x1
- Oled SSD1306 x1
- Buzzer x1
This schematic outlines the interconnections between an ESP32 microcontroller and various peripheral components, including an RFID-RC522 module, an OLED display, an LED, and a Buzzer. The connections are specified via General-Purpose Input/Output (GPIO) pins, designated for specific signal transmissions that enable communication between the ESP32 and the peripherals. Software Concept below is a detailed breakdown of the connections.
By utilizing the GPIOs of the ESP32 and SPI & I²C interface support, the project is able to control the following components:
- GPIO2: This reset line is connected from the ESP32 to the RST pin on the RFID-RC522. It is used to reset the RFID module.
- GPIO5: The SS pin on the RFID-RC522 is connected to GPIO5 on the ESP32. This pin enables the ESP32 to select the RFID-RC522 module for communication over the SPI interface.
- GPIO21: The SDA line of the I²C interface for the OLED display is connected to GPIO21. This line is used for data transfer between the ESP32 and the OLED.
- GPIO22: The SCL line of the I²C interface links GPIO22 on the ESP32 with the corresponding SCL input on the OLED. This line provides the clock signal that synchronizes data transmission.
- GPIO13: An LED is connected to GPIO13 on the ESP32. This setup allows the ESP32 to control the LED, turning it on or off by setting GPIO13 high or low, respectively.
- GPIO4: The Buzzer is connected to GPIO4 on the ESP32. By toggling GPIO4 high and low at various frequencies, the ESP32 can control the buzzer to generate different tones.
- Initialize the U8X8 display, LED pin, buzzer pin, and RFID module.
- Retrieve the index along with the three most recent IDs from the Preferences library.
- Display the three most recent IDs on the screen.
- Check if the newly scanned card matches the previously scanned card; if it does, do not process the new card scan.
- Activate the buzzer and turn on the LED light to signal a successful scan.
- Update the storage with the three most recent card IDs and increment the counter by one.
- Save the updated values and the counter increment back to the Preferences library - which uses a portion of the on-board non-volatile memory (NVS) of the ESP32 to store data.