Overview

This project allows you to control four relays using an ESP8266 (NodeMCU) via the Arduino IoT Cloud. You can toggle relays using physical switches or control them remotely from anywhere using a cloud-based dashboard.

🎯 Key Features:

✅ Manual Control – Use physical switches to toggle relays.

✅ Remote Control – Control the relays from the Arduino IoT Cloud Dashboard.

✅ WiFi Connectivity – Get real-time feedback on the relay status.

✅ Synchronization – Changes from manual and cloud control stay updated.

Circuit Diagram

🖼️ Follow the wiring diagram below to connect your components:

Wiring Details:

Relays:

Relay 1: GPIO 5 (D1)

Relay 2: GPIO 4 (D2)

Relay 3: GPIO 15 (D8)

Relay 4: GPIO 13 (D7)

Switches:

Switch 1: GPIO 0 (D3)

Switch 2: GPIO 2 (D4)

Switch 3: GPIO 14 (D5)

Switch 4: GPIO 12 (D6)

Step-by-Step Instructions

1️⃣ Install Required Libraries

Open the Arduino IDE and install the following libraries via the Library Manager:

ArduinoIoTCloud

Arduino_ConnectionHandler

2️⃣ Configure Arduino IoT Cloud

Go to Arduino IoT Cloud and create a new Thing.

Add the following Cloud Variables:

relay1 (type: CloudSwitch)

relay2 (type: CloudSwitch)

relay3 (type: CloudSwitch)

relay4 (type: CloudSwitch)

Link these variables to a toggle switch in the dashboard.

3️⃣ Upload the Code to ESP8266

Connect the ESP8266 to your computer.

Upload the following Arduino Sketch (after replacing WiFi credentials and Cloud Keys):

#define RelayPin1 5 // D1
#define RelayPin2 4 // D2
#define RelayPin3 15 // D8
#define RelayPin4 13 // D7

#define SwitchPin1 0 // D3
#define SwitchPin2 2 // D4
#define SwitchPin3 14 // D5
#define SwitchPin4 12 // D6

CloudSwitch relay1;
CloudSwitch relay2;
CloudSwitch relay3;
CloudSwitch relay4;

void setup() {
 pinMode(RelayPin1, OUTPUT);
 pinMode(RelayPin2, OUTPUT);
 pinMode(RelayPin3, OUTPUT);
 pinMode(RelayPin4, OUTPUT);
 pinMode(SwitchPin1, INPUT_PULLUP);
 pinMode(SwitchPin2, INPUT_PULLUP);
 pinMode(SwitchPin3, INPUT_PULLUP);
 pinMode(SwitchPin4, INPUT_PULLUP);
}

void loop() {
 if (digitalRead(SwitchPin1) == LOW) {
  relay1 = !relay1;
  digitalWrite(RelayPin1, relay1 ? LOW : HIGH);
 }
}

4️⃣ Test Your Project

Press the physical switches to control the relays.

Use the Arduino IoT Cloud Dashboard to toggle the relays remotely.

Future Improvements

🔹 Add real-time feedback (LEDs for relay status).

🔹 Expand control for more devices.

🔹 Add timer scheduling for automation.