Smart Multiplug





Introduction: Smart Multiplug

Every day we all waste so much electricity. We forget to switch off the TV ,fan or any other electrical appliance.
This harms our environment as well are pockets. If you fall asleep while watching television and forget to switch it off
and it's your daily routine then you could loose upto or more then $55 a year, so I am presenting " the smart multiplug ".

This is a smart plug which switches off appliances connected to itself if the appliances are not being used.
We can also view the status of the appliance on our phones and use it as a remote to switching on and off the appliances.
It has got two sockets and a maximum of 1100 watt can be drawn safely from the plugs.
This device has got a safety cut off which I will explain ahead in the instructable.

Disclaimer: This project works on 240v ac which is quite dangerous if you don't take safe measures while working with it. If you do something wrong and if it results in a damage, I am not responsible in any way. Make this at your own risk. YOU HAVE BEEN WARNED!

Step 1: Some Features

Here are the feature of this device
this device is equipped with a motion sensor so if no motion is detected in a particular time (which can be changed) ,
then it cuts off the current hence saving a lot of electricity

this device has Bluetooth, so you can use your phone (android) as a remote or you can check the status of the appliance that is the appliance 'on' or 'off'.

since the outer covering is made of MDF board (which of course does not conduct electricity) this device is shock resistant.

Since it has got two plugs it acts as multiplug and two appliances can be used instead of one.

There are very little chances of fire but it is necessary to make the device fire proof.

A fuse has been attached, so this is a safety device. It the current exceeds the limit the fuse will cut off, thereby protecting the appliances.

- maximum current 7A
- maximum voltage 250volts
-maximum wattage 1750watts

- safe current 5A
-safe voltage 220v
- safe wattage 1100watts

8)small in size and looks nice (I think).

This device cuts off current if not being used hence safes a lot of electricity.
If you forget to switch of a 1000 watt heater for three hours, 3 units of energy will be wasted
Which will saved if using smart plug

Step 2: My Concept, Design and Why I Made It

The main idea of making this device is to save electricity. This device is controlled by an Arduino, and has a relay, motion sensor and few other parts inside. If a television is connected to this plug and you sleep while watching television so it will automatically switch off after fifteen minutes.
Also sometimes you go to sleep and forget to switch off the light and feel to lazy to get out off bed, then you can switch the light using your phone.

this device is a small box with two sockets at the back and sensors at front.
There are also air vents to prevent heating of the transformer and the relay.
The main design can be seen in the pictures. I have sketched the view from each side. ( I'm not very good with 3d designing on computers so I sketched. Hope it's not a problem)
The dimensions are -
12.2x8x8 cms

the reason making is clear- to save electricity and making our lives easier.
Before making this device, I was wondering that how much electricity is wasted in the whole world. So I searched the net and found that about
Half of the world does not have electricity and we are wasting 75% of the energy which we pay for. So I wanted to make a device which could save a little energy. I know this device cannot save mega watt's of power but it can have a little affect on your electricity bill.

Step 3: Materials in Making the Case (hardware)

Making the case I had an option of Aluminium sheets, wood, and MDF board.

The reason for not choosing is, ONE it conducts electricity so it is not shock proof, TWO it's expensive, THREE if I used it I had to paint it to make it look nice,therefore increasing the cost.

WOOD- rejected
I did not choose it because I have no idea about carpentry and to make it look nice I had to polish it and again I have zero skills of polishing

MDF- selected
I choosed MDF because it does not conduct electricity, easy to use, cheap and looks nice without painting or polishing.

Step 4: Cutting the Pieces

To make the pieces I actually did nothing because I had them already lasercut, so I do not have any files
but I have given the design of each side in the pictures.

Step 5: Making the Case

This is an easy step.
You have to just join the pieces together with adhesive as shown in the picture.
Just join the lower, front and the sides.
Leave the top and back side. We will join it in later steps

Step 6: The Divisions in the Circuit

To make the circuitry convenient, I have divided the circuit into three major phases.
The first phase includes wiring with high tension wires and the part of circuit which will handle 220 volts.
It includes relay, sockets and the plug wiring.

The second phase includes Arduino, Bluetooth and motion sensor. It has all the parts which operate at 5volts or less.

The third phase has the voltage regulator which converts 220volts to 5volts for Arduino.

Step 7: Materials and Cost (electronic)

Parts No. Of pieces Cost
Arduino uno 1 ₹ 300
Relay board 2 ₹ 100
Transformer 1 ₹ 50
Socket 2 ₹ 60
Pcb 1 ₹ 5
5volt regulator 1 ₹ 5
Bluetooth 1 ₹200
Motion sensor 1 ₹ 60
3 pin plug. 1 ₹40
Total. ₹ 770 + shipping
Some electrical wire
7A/250volts A/C and 10A/24 volts D/C

I have used a step down transformer with
Input: 80- 240 volts, 50 Hz AC
Output: 12 volts DC one amp.

3) sockets
The sockets used are 5 pin sockets suitable with maximum 6A current and 250v.

Hc05 Bluetooth module has been used.

5)motion sensor
A normal hobby motion sensor has been used which can be operated at 3.3 to 5 volts

The plug used is a 6A domestic light, which has three pins. Maximum voltage is 250 volts.

7) wires
The wires used are which are used for home wiring. They can carry upto 1100 volts and
have an area of cross section of 1.5mm sq.

Step 8: Connecting Relay to the Sockets and Power Source (phase One)


-Connect the NO of the relay to the neutral wire from the power source
-C of relay to neutral of the socket
-the live of socket to the live wire
- earth of each socket to earth wire
Repeat the same for the second relay and socket.


-Connect pin 1 of relay to 7 Arduino
-Connect pin 2 of relay to 6 Arduino
-12 v relay to Arduino 5v
- GND relay to gnd Arduino

Step 9: Making the Plug Circuit (part of Phase One)

Take three 1100volts wires about one meter in length.

Connect one wire to earth, one to live, and one to neutral.
Now connect the earth of plug to earth of sockets

Step 10: Arduino to Motion Sensor and Bluetooth (phase Two)

Jumper wires are used for these connections

Motion sensor
- vcc to 5v Arduino
- out to 8 Arduino
- GND to GND arduino

- 5v to 3v Arduino
- GND to GND Arduino

Step 11: Making the Voltage Regulator( Phase Three)

To make the regulator you need
-7805 5v regulator
-A AC TO DC 240to 12v transformer
- pcb
-soldering materials

-Connect each of the input to the live and neutral wire as shown in the diagram
This is to step down the voltage to 12v
-Connect positive output to the in of the 5v regulator (this is to step down to 5v).
-Negative terminal of the output of transformer to GND of 5v regulator
-Output of 5v regulator to 5v Arduino

Solder a wire from GND of voltage regulator and connect it to Arduino gnd

Step 12: Connecting All the Phases (complete Circuit)

In connecting the phases we will start from connecting phase two and phase three.
This is a very simple step. Just connect the 5v output to Arduino 5v or vcc and
Connect the GND of regulator to Arduino GND.

Connecting phase 1 & 2
Connect pin 1 relay to pin 7 Arduino
Pin 2 relay to pin 6 Arduino
GND relay to GND Arduino
12v relay to 5 volts arduino

Now we are done with all the connections, it's programming time now.

Step 13: The Program

I have written two codes, one with and one without Bluetooth.
Both are attached below

int motionsensor=8;
int relay1=7;
int relay2=6;

void setup()

digitalWrite(relay1, LOW);
digitalWrite(relay2, LOW);

void loop()

while (digitalRead(motionsensor) == HIGH)
digitalWrite(relay1, HIGH);
digitalWrite(relay2, HIGH);
Serial.println("Relay is ON");


while (digitalRead(motionsensor) == LOW)
digitalWrite(relay1, LOW);
digitalWrite(relay2, LOW);
Serial.println("Relay is OFF");



int motionsensor=8;
int relay1=7;
int relay2=6;
int flag=0;
int state;
void setup()

digitalWrite(relay1, LOW);
digitalWrite(relay2, LOW);

void loop()
if(Serial.available() > 0) {

state =;
if (state == '0')


while (digitalRead(motionsensor) == HIGH)
digitalWrite(relay1, HIGH);
digitalWrite(relay2, HIGH);

Serial.println("appliance status: on");

while (digitalRead(motionsensor) == LOW)
digitalWrite(relay1, LOW);
digitalWrite(relay2, LOW);
Serial.println("appliance status: off");


Step 14: Uploading the Code

Now upload the code from you pc to Arduino
But don't forget to take the TX AND RX WIRES, because they may interfere in uploading the code



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    15 Discussions

    very good instructable :)

    I'd recommend using the correct mains wire however, you could even reuse some old cable from say an old toaster or something :D

    Health & Safety Using single insulation cable for the 240v mains feed would make this illegal in the UK.

    1 reply

    A simple remark about safety. It's always better to cut live wire instead of neutral, and for several reasons : You can touch the neutral wire without risking electrocution. In a multiphase system cutting neutral generally destroys receivers.

    8 replies

    If you don't need Bluetooth then you can just leave the Arduino out completely. The motion sensor outputs 5 volts, you can put 5 volt output directly to the relay board and skip the programming completely. even better most of the relay boards I found have a 5 volt output built into them which case you can run that directly to the PIR sensor Vin. I have done this with a LED lighting project but because it was battery powered I did not want to add an Arduino and lower the battery life.

    Yes i can do that but then i wont be able to give a delay of ten minutes before switching off

    All the pir sensors i have come with 2 potentiometers on the side, you rotate 1 for sensitivity (never made much of a change for me) the other is the duration of the signal, most of mine will go 30 min to a hour. If you really want to throw a arduino in there as a timer or to add functions try a nano or trinket version, tiny and super cheap. Just limits you to fewer pins. I can get a nano clone for 2 or 3 dollars. Another cheap option if you are trying to learn new skills would be to build you own 555 timer circuit. Very important and useful IC to know. A 555 and a few resistors or potentiometers a capacitor you can have a adjustible timer for .50 cents. I just like to scratch build things to learn, you could buy a pir activated switch from a hardware store for 8 bucks or like me spend hours breacking down, you can biuld a easy pir sensor your self out of 3 ir leds and one ir photo resistor. A relay from a resistor a mosfet or small transistor and on and on... depends on what you want to learn first and how big of steps you want to take. Happy MAKEing!

    but my pir sensor just has a delay of 5-200 seconds. Yes making it with 555 timer would be a good option, but i don't have much knowledge and experience with 555 timer.

    Thanks for suggestions and reading my ible


    2 years ago

    I am not sure if this is a coincidence or not but the 'Disclaimer' lines were same as my bedroom automation project! :D

    1 reply

    hey Saiyam It might be a coincidence because I searched on Internet for a

    220 volt disclaimer and I found one and copy pasted that:)

    And differential protections won't work fine as well.