Below given is Relay Driver Circuit to build your own Relay module: Circuit Diagram and Working: In this Arduino Relay Control Circuit we have used Arduino to control the relay via a BC547 transistor.

Example code of Arduino interfacing with single channel relay module int relay_pin = 7; void setup() { pinMode(relay_pin,OUTPUT); } void loop() { digitalWrite(relay_pin,HIGH); delay(2000); ...

Circuit Diagram: Relay module: Connect the IN pin of the relay to a GPIO pin (e.g., D1 or GPIO5). ESP8266 or ESP32: Make sure the relay module's VCC and GND are properly connected to the board.

Fig. 3: Circuit diagram of the voice-controlled home automation system Bluetooth module HC-05 transmits and also receives data serially via Board1 that can be read by the microcontroller (MCU). A ...