Circuit Documentation

Summary

This circuit is designed to control various devices such as a fan, a bulb, and an AC bulb using an Arduino UNO microcontroller. The control is facilitated through a 4-channel relay module and an HC-05 Bluetooth module, allowing wireless communication. Additionally, a Tower Pro SG90 servo motor is included for mechanical actuation. The circuit is powered by a 7.4V battery and an AC supply.

Component List

1. Arduino UNO

   • Description: A microcontroller board based on the ATmega328P.
   • Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0, A1, A2, A3, A4, A5, SCL, SDA, AREF, D13, D12, D11, D10, D9, D8, D7, D6, D5, D4, D3, D2, D1, D0

2. Relay 4 Channel 5v

   • Description: A relay module that allows control of high voltage devices.
   • Pins: GND, IN1, IN2, IN3, IN4, VCC, COM1, COM2, COM3, COM4, NO1, NO2, NO3, NO4, NC1, NC2, NC3, NC4

3. HC-05 Bluetooth Module

   • Description: A Bluetooth module for wireless communication.
   • Pins: Key, VCC, TXD, RXD, State, GND

4. Tower Pro SG90 Servo

   • Description: A small servo motor for precise control of angular position.
   • Pins: Signal, +5V, GND

5. BULB

   • Description: A standard DC bulb.
   • Pins: +, -

6. Fan

   • Description: A 5V DC fan.
   • Pins: GND, 5V

7. Power Outlet (IL)

   • Description: A power outlet for AC devices.
   • Pins: N, L, GND

8. 7.4V Battery

   • Description: A 7.4V battery for powering the circuit.
   • Pins: +, -

9. AC Supply

   • Description: An AC power supply.
   • Pins: +ve, -ve

10. AC Bulb

    • Description: An AC bulb.
    • Pins: P, N

Wiring Details

Arduino UNO

• 5V: Connected to VCC of Relay 4 Channel 5v, VCC of HC-05 Bluetooth Module, and +5V of Tower Pro SG90 Servo.
• GND: Connected to GND of Relay 4 Channel 5v, GND of HC-05 Bluetooth Module, GND of Tower Pro SG90 Servo, and - of 7.4V Battery.
• Vin: Connected to + of 7.4V Battery.
• D11: Connected to Signal of Tower Pro SG90 Servo.
• D5: Connected to IN4 of Relay 4 Channel 5v.
• D4: Connected to IN3 of Relay 4 Channel 5v.
• D3: Connected to IN2 of Relay 4 Channel 5v.
• D2: Connected to IN1 of Relay 4 Channel 5v.
• D1: Connected to RXD of HC-05 Bluetooth Module.
• D0: Connected to TXD of HC-05 Bluetooth Module.

Relay 4 Channel 5v

• VCC: Connected to 5V of Arduino UNO.
• GND: Connected to GND of Arduino UNO.
• IN4: Connected to D5 of Arduino UNO.
• IN3: Connected to D4 of Arduino UNO.
• IN2: Connected to D3 of Arduino UNO.
• IN1: Connected to D2 of Arduino UNO.
• COM1, COM2, COM3, COM4: Connected to +ve of AC Supply.
• NO1: Connected to L of Power Outlet (IL).
• NO2: Connected to 5V of Fan.
• NO3: Connected to + of BULB.
• NO4: Connected to P of AC Bulb.

HC-05 Bluetooth Module

• VCC: Connected to 5V of Arduino UNO.
• GND: Connected to GND of Arduino UNO.
• RXD: Connected to D1 of Arduino UNO.
• TXD: Connected to D0 of Arduino UNO.

Tower Pro SG90 Servo

• Signal: Connected to D11 of Arduino UNO.
• +5V: Connected to 5V of Arduino UNO.
• GND: Connected to GND of Arduino UNO.

BULB

• +: Connected to NO3 of Relay 4 Channel 5v.
• -: Connected to GND of Fan, GND of Power Outlet (IL), N of AC Bulb, and -ve of AC Supply.

Fan

• 5V: Connected to NO2 of Relay 4 Channel 5v.
• GND: Connected to - of BULB.

Power Outlet (IL)

• L: Connected to NO1 of Relay 4 Channel 5v.
• GND: Connected to - of BULB.

7.4V Battery

• +: Connected to Vin of Arduino UNO.
• -: Connected to GND of Arduino UNO.

AC Supply

• +ve: Connected to COM1, COM2, COM3, COM4 of Relay 4 Channel 5v.
• -ve: Connected to - of BULB.

AC Bulb

• P: Connected to NO4 of Relay 4 Channel 5v.
• N: Connected to - of BULB.

Code Documentation

long int ac=2;
long int bulb=3;
long int heater=4;
long int fan=5;
char x;

void setup()
{
    pinMode(ac, OUTPUT);
    pinMode(bulb, OUTPUT);
    pinMode(heater, OUTPUT);
    pinMode(fan, OUTPUT);
    digitalWrite(ac, HIGH);
    digitalWrite(bulb, HIGH);
    digitalWrite(heater, HIGH);
    digitalWrite(fan, HIGH);
    Serial.begin(9600); 
}

void loop()
{
    if(Serial.available() > 0)
    {
        x = Serial.read();
    }
    if(x == 'a')
        digitalWrite(ac, LOW);
    if(x == 'b')
        digitalWrite(ac, HIGH);
    if(x == 'c')
        digitalWrite(bulb, LOW);
    if(x == 'd')
        digitalWrite(bulb, HIGH);
    if(x == 'e')
        digitalWrite(heater, LOW);
    if(x == 'f')
        digitalWrite(heater, HIGH);
    if(x == 'g')
        digitalWrite(fan, LOW);
    if(x == 'h')
        digitalWrite(fan, HIGH);
}

This code initializes the pins connected to the relay module as outputs and sets them to a high state (off). It then reads commands from the Bluetooth module to control the state of the relays, thereby controlling the connected devices.