greetings
in times of the pandemic of covid-19
it is a necessity to avoid contact and maintain social distancing
but to turn on and off the appliances you need to touch the switchboards
but wait not any more
introducing contact less system for controlling lights
imagine you controlling your appliances with a device you always carry along
yes this is possible
you can control the appliances with your fingertips without actually going to the switchboard

m a student 12th grade

Step 1: Components

this is a very basic project to control 4 appliances
u will need
arduino uno
bluetooth module
relay module
and a few jumper wires

Step 2: Time to Program the Setup

first upload this program onto your arduino uno
"bluetooth SAPWR" is code for a single appliance
"4 led home automation" is a code for 4 appliances
but you can easily alter the code or just copy paste the led fuctions to increase the number of appliances and also increase the number of relays u will be using

i am going with the 4 led setup with the default 4 relay module

note:-
check the rating of the relay you are using or it can damage the relay

Step 3: Wiring

i have set pin 13,12,11,10 as the 4 pins for the output
u need to wire the 5v and ground of the relay module and bluetooth module
the tx of hc-05 goes to rx of the arduino(pin 0)
the rx of the hc-05 goes to tx of the arduino(pin1)

the 4 pins
13,12,11,10 all go to the respective relay input pins generally labelled as in1,in2,in3,in4

then u need to download any bluetooth serial terminal
i am using this application as it enables to set a custom preset for my appliances
so instead of typing an alphabet everytime
i just have to click of the respective preset button for the function to start
the different funtions are
'a'-turns on first led

'b'-turns off first led

'c'-turns on 2nd led

'd'-turns off 2nd led

'e'-turns on 3rd led

'f'-turns off 3rd led

'g'-turns on 4th led

'h'-turns off 4th led

if everything is all fine your basic setup is all ready and now you need to just mount it into your mains switchboard

the video of how it responds is embedded along

Step 4: Mounting in the Mains

so every relay output has 3 pins
the middle one for the live wire
and the one side is normally closed(meaning its live when the relay is not activated)
the other side is normally open(meaning its not live when the relay is not activated)
you can easily test which one is which by using a multimeter
so depending on the requirement and frequency of use you can select which pin you want to use
in my case
i have wired the normally open with the appliance wire as i dont keep the lights on for a very long duration

but it does not create any significant difference

all it will change is the input key

for me now 'a' turns on the appliance and 'b turns off the appliance

but if u wire the normally closed with the appliance wire

'b' will turn on and 'a' will turn off the appliance

so this step might alter your input keys for the usage

then all u need to do is make a compact box for the setup

and mount it near the switchboard with a 5v usb charger adapter to power the appliance

Step 5: Final Perspective

the bluetooth can pair with only one user at a time
but the advantage is that the number of devices that can use the setup with is not limited
all it needs is any device with bluetooth and a bluetooth terminal installed

this is not that graphically enhanced from a user perspective

future modifications will be creating a graphical user interface that enables the user to use this setup more conveniently
and using an arduino nano to make the setup more smaller and easier to mount

but its a one for all product

its a single product for all lazy people who are just too lazy to get up and go to the switchboard

also

it reduces the physical contact with the switchboard
thereby maintaining the social distancing

applications are far more than i can list
-home automation for household appliances
-common lighting of societies
-workplace and offices
-can be used for any wireless control upto range of 15-20m

hope you liked this project