Hi guys in this instructable I'll show you how to control (9W 220-240V) BULB using arduino and android phone.

Step 1: ​Components Required

1) Arduino Uno

2) Bluetooth Module HC-05

3) Relay

4) Bulb 9W 220V (obviously :D)

5) Breadboard

6) Bulb Holder

7) some jumper wires

8) Android Smartphone

Step 2: Connect Bluetooth and Relay on ARDUINO

In Bluetooth Module HC-05 have 6 pins but we're using only 4 pins

RX (Receive Clock )

TX (Transmit Clock )



And Relay have mainly 3 pins (if you're using 1ch relay)




-connect the bluetooth rx pin to the arduino tx pin

-connect the bluetooth tx pin to the arduino rx pin

-connect the relay and bluetooth 5v and vcc pin to the arduino 5v pin using breadboard

-connect GND pin same as a 5v.

note : 1 connection is remain i'll show you in next step.

Step 3: RELAY Connection

So now in relay have 3 connection(shown in image)

NO - Normal Open

C - Common

NC - Normal Close

-Normal Open(NO) connect to the bulb Positive.

-Common connect to the plug positive.

-bulb another wire connect to the plug's second wire.

so here all connection is ready !

Step 4: Arduino Code

// NOTE : in this code i'm using CH3 but its depend on which channel you're using so if you use channel 2 then you type the( CH2 7 ) and 7 is the number of pin which we connect through the channel 2 //

String voice;

#define CH1 7

void setup() {


pinMode(CH1, OUTPUT);



void loop()

while (Serial.available()) {


char c = Serial.read();

if (c == '#') {break;}

voice += c;


if (voice.length() > 0) {


if(voice == "*switch on") {digitalWrite(CH1, LOW);}

else if(voice == "*switch off") {digitalWrite(CH1, HIGH);}

voice=" ";}}

Step 5: Download the Android App


after download the app

go to the connect robot

and say switch on and switch off !


if any query then ask me... comment section below

<p>hello sir , how to add this code to arduino library ? there is no .h file , sorry im new</p>
<p>Sir! Your work is great! Ahm, I would like to ask if it is possible for us have more than one output aside from the 220V bulb? Just like making a Home Automation</p>
<p>This is really cool. It would be great to hook this up to control the coffee maker. That way the coffee is already there when you get to the kitchen.</p>

About This Instructable




Bio: College student.. Arduino, Raspberry pi and 3d printer lover !
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