Circuit Documentation

Summary

This circuit integrates various components to achieve a multifunctional system. It includes microcontrollers (ESP8266 NodeMCU and Arduino Nano), communication modules (NRF24L01, SIM900A), a bi-directional logic level converter, a fingerprint scanner, a buzzer module, an OLED display, and an RFID-RC522 module. The circuit is designed to handle wireless communication, fingerprint scanning, RFID reading, and user interaction through a display and audio feedback.

Component List

Microcontrollers

• ESP8266 NodeMCU: A Wi-Fi enabled microcontroller with multiple digital and analog pins.
• Arduino Nano: A compact microcontroller with digital and analog I/O pins.

Communication Modules

• NRF24L01: A wireless transceiver module for enabling RF communication.
• SIM900A: A GSM/GPRS module for cellular network communication.

Sensors and Actuators

• Fingerprint Scanner: A biometric sensor for fingerprint detection and verification.
• Buzzer Module: An audio signaling device.

Display

• 128x64 OLED Display (I2C IIC SPI Serial): A small screen for displaying text and graphics.

Other Components

• Bi-Directional Logic Level Converter: A device to safely step down or step up signal voltages between different logic levels.
• RFID-RC522: An RFID reader/writer module.

Wiring Details

ESP8266 NodeMCU

• GND: Connected to the common ground net.
• VIN: Connected to the 5V power net.
• D2: Connected to NRF24L01 CE pin.
• D4: Connected to NRF24L01 CSN pin.
• D5: Connected to NRF24L01 SCK pin.
• D6: Connected to NRF24L01 MISO pin.
• D7: Connected to NRF24L01 MOSI pin.
• RX: Connected to SIM900A RXD pin.
• TX: Connected to SIM900A TXD pin.

Arduino Nano

• 5V: Connected to the 5V power net.
• GND: Connected to the common ground net.
• D2: Connected to Fingerprint Scanner TX pin.
• D3: Connected to Fingerprint Scanner RX pin.
• D6: Connected to Buzzer Module I/O pin.
• D9: Connected to NRF24L01 CE pin.
• D10: Connected to RFID-RC522 SDA and NRF24L01 CSN pins.
• D11/MOSI: Connected to RFID-RC522 MOSI and NRF24L01 MOSI pins.
• D12/MISO: Connected to RFID-RC522 MISO and NRF24L01 MISO pins.
• D13/SCK: Connected to RFID-RC522 SCK and NRF24L01 SCK pins.
• A4: Connected to OLED Display SDA pin.
• A5: Connected to OLED Display SCL pin.

NRF24L01

• GND: Connected to the common ground net.
• VCC (3V): Connected to the 3.3V power net.
• CE, CSN, SCK, MISO, MOSI: Connected to corresponding pins on ESP8266 NodeMCU or Arduino Nano as detailed above.

SIM900A

• GND: Connected to the common ground net.
• 5V: Connected to the 5V power net.
• RXD: Connected to ESP8266 NodeMCU TX pin.
• TXD: Connected to ESP8266 NodeMCU RX pin.

Fingerprint Scanner

• VCC: Connected to the 5V power net.
• GND: Connected to the common ground net.
• TX: Connected to Arduino Nano D2 pin.
• RX: Connected to Arduino Nano D3 pin.

Buzzer Module

• Vcc: Connected to the 5V power net.
• GND: Connected to the common ground net.
• I/O: Connected to Arduino Nano D6 pin.

OLED Display

• VCC: Connected to the 3.3V power net.
• GND: Connected to the common ground net.
• SDA: Connected to Arduino Nano A4 pin.
• SCL: Connected to Arduino Nano A5 pin.

Bi-Directional Logic Level Converter

• GND: Connected to the common ground net.
• LV: Connected to the 3.3V power net.
• HV: Connected to the 5V power net.
• LV1, LV2: Connected to 3.3V power net or NRF24L01 VCC as detailed above.
• HV1, HV2: Connected to 5V power net as detailed above.

RFID-RC522

• VCC (3.3V): Connected to the 3.3V power net.
• GND: Connected to the common ground net.
• SDA, MOSI, MISO, SCK: Connected to corresponding pins on Arduino Nano as detailed above.

Documented Code

Arduino Nano Code (sketch.ino)

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}

Note: The provided code for the Arduino Nano is a template with empty setup and loop functions. This code needs to be populated with the logic required to control the connected components based on the desired functionality of the circuit.