Circuit Documentation

Summary

This circuit integrates an ESP32 microcontroller with a 433 MHz RF transmitter and receiver module to facilitate wireless communication. The ESP32 is programmed to handle Bluetooth data, decode RF signals, and control an LED indicator based on the received signals. The RF transmitter is used to send data wirelessly, while the RF receiver module captures incoming RF signals for processing by the ESP32.

Component List

ESP32 (30 pin)

• Description: A microcontroller with Bluetooth and Wi-Fi capabilities, featuring a variety of digital and analog pins.
• Purpose: Acts as the central processing unit for the circuit, handling Bluetooth communication, RF signal decoding, and LED control.

RF 433 MHz Transmitter

• Description: A module capable of transmitting RF signals at 433 MHz.
• Purpose: Sends RF signals as instructed by the ESP32.

433 MHz RF Receiver Module

• Description: A module capable of receiving RF signals at 433 MHz.
• Purpose: Captures RF signals for the ESP32 to decode and process.

Wiring Details

ESP32 (30 pin)

• D4: Connected to the Data pin of the RF 433 MHz Transmitter.
• D2: Connected to the DATA pin of the 433 MHz RF Receiver Module.
• GND: Common ground shared with the RF 433 MHz Transmitter and the 433 MHz RF Receiver Module.
• 3V3: Power supply for the ESP32, also connected to the VCC of the 433 MHz RF Receiver Module and the +ve of the RF 433 MHz Transmitter.

RF 433 MHz Transmitter

• Data: Connected to the D4 pin of the ESP32.
• -ve: Connected to the GND of the ESP32.
• +ve: Connected to the 3V3 pin of the ESP32.

433 MHz RF Receiver Module

• VCC: Connected to the 3V3 pin of the ESP32.
• DATA: Connected to the D2 pin of the ESP32.
• GND: Connected to the GND of the ESP32.

Documented Code

// The script is written by Slavko Zdravevski
// If you want to support my work, you can subscribe to my youtube channel: https://bit.ly/3FG9hpK
// I do a lot of interesting things in my free time, so you might find something of your interest or we can exchange ideas and knowledge

// Libraries, I also put them on github
#include "BluetoothSerial.h"
#include <RCSwitch.h>

// Pinout declaration
int ledPin = 13;
int rfReceiverPin = 2;
int rfTransmitterPin = 4; 

// Additional variables needed through the code
unsigned long currentSecounds, previousSecoundsRecord;
String receivedCommand;
String commandToSend;

unsigned long receivedCodes[100];
int receivedProtocols[100];
int receiverCounter = 0;
bool canStoreCurrentCode = true;
unsigned long previousMillisLed = 0;
bool blinkLed = false;
int ledCounter = 0;

BluetoothSerial SerialBT;
RCSwitch mySwitch = RCSwitch();

void setup() {
  Serial.begin(115200);
  SerialBT.begin("ESP32"); // If you want to use my app, leave this line as it is, otherwise, it won't work
  mySwitch.enableReceive(rfReceiverPin);
  mySwitch.enableTransmit(rfTransmitterPin);
  pinMode(ledPin, OUTPUT);
}

void loop() {
  currentSecounds = millis() / 1000;
  receiveBtData();
  decodeRfSignals();
  checkLedState();
  
  if ((currentSecounds - previousSecoundsRecord) >= 4) {
    previousSecoundsRecord = currentSecounds;
    SerialBT.println("Good connection");
  }
}

// Method declarations
void receiveBtData() { // Receives Bluetooth data sent from the Android device and acts accordingly
  if (SerialBT.available()) {
    receivedCommand += String((char)SerialBT.read());
  } else {
    receivedCommand.toLowerCase();
    if (receivedCommand != "") {
      Serial.println(receivedCommand);
      if (receivedCommand == "refresh data") {
        sendCurrentRfData();
      } else {
        int codeForSend = receivedCommand.substring(0,receivedCommand.indexOf("|")).toInt();
        int protocolForSend = receivedCommand.substring(receivedCommand.indexOf("|")+1, receivedCommand.length()).toInt();
        Serial.println(codeForSend);
        Serial.println(protocolForSend);
        sendCodeOverRfModule(codeForSend, protocolForSend);
      }
      receivedCommand = "";
    }
  }
}

void sendCurrentRfData() { // Sends the currently stored data in the microcontroller's memory to the phone over Bluetooth
  if (receiverCounter != 0) {
    for (int i=0; i<receiverCounter; i++) {
      commandToSend = String(receivedCodes[i])+"|"+String(receivedProtocols[i]);
      SerialBT.println(commandToSend);
      delay(200);
    }
  } else {
    SerialBT.println("empty memory");
  }
}

void sendCodeOverRfModule(int code, int protocol) { // Sends the code got from the parameter over the radio module
  blinkLed = true;
  // Optional set protocol (default is 1, will work for most outlets)
  mySwitch.setProtocol(protocol);
  mySwitch.send(code, 24);
}

void decodeRfSignals() { // Decodes the 433/315 signals received by the module, and stores them into local arrays
  if (mySwitch.available()) {
    blinkLed = true;
    for (int i=0; i<receiverCounter; i++) {
      if (receivedCodes[i] == mySwitch.getReceivedValue()) {
        canStoreCurrentCode = false;
        break;
      }
    }

    if (canStoreCurrentCode) {
      receivedCodes[receiverCounter] = mySwitch.getReceivedValue();
      receivedProtocols[receiverCounter] = mySwitch.getReceivedProtocol();

      Serial.println(mySwitch.getReceivedValue());
      Serial.println(receiverCounter);
      receiverCounter++;
    }

    canStoreCurrentCode = true;

    mySwitch.resetAvailable();
  }
}

void checkLedState() { // Checks whether the led should blink
  unsigned long currentMillisLed = millis();  
  if (blinkLed) {
    if ((unsigned long)(currentMillisLed - previousMillisLed) >= 100) {
      if (ledCounter == 0) {
        digitalWrite(ledPin, HIGH);
        ledCounter = 1;
      } else if (ledCounter == 1) {
        digitalWrite(ledPin, LOW);
        ledCounter = 2;
      } else if (ledCounter == 2) {
        digitalWrite(ledPin, HIGH);
        ledCounter = 3;
      } else if (ledCounter == 3) {
        digitalWrite(ledPin, LOW);
        ledCounter = 0;
        blinkLed = false;
      }
      previousMillisLed = currentMillisLed;
    }
  }
}

This code is designed to be uploaded to the ESP32 microcontroller. It includes functionality for Bluetooth communication, RF signal transmission and reception, and LED control. The code is well-commented, providing clarity on the purpose and functionality of each section.