# My journey into the world of IoT

## WHOAMI?

---

Let me introduce myself. I'm a student who is interested in **electronics**, I know that I threw a pretty vague term there but lemme explain. When I was very young, maybe in 6th std (excuse me I don't know the exact year) my sister gave me a light bulb, one with a filament on it. From there my interest in electronics started and later aligned with the field of computers... cause

```plaintext
COMPUTERS == APPLICATION_OF_ELECTRONICS
```

---

Back in the year 2k21, this was the year after I started college. I used to watch build videos of electronic projects like LED cube matrix or POV displays but in the end, something I wanted to do out of my \*\*curiosity \*\*, of knowing how those devices would work, and that stuff really fascinated me.

![LEDCubeFinalOperational.webp](https://cdn.hashnode.com/res/hashnode/image/upload/v1660142501799/JoGKyUfMQ.webp align="left")

After getting loaded with a bunch of electronic project ideas, there was one project which stuck on my mind for a very long time. In that project, I wanted to control my home light bulbs and fans via my smartphone. Then my research journey began...

## Let the journey begin

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I was not sure how to achieve that result, thus I started **Dorking Google**. I saw the most common method to achieve my result, and that was using services like **Arduino IoT cloud** or **Blynk**, etc. At that time I had only one board which was **Raspberry pi 3**. Because of the following factors, i could not use those appealing services :

* I wasn't aware of the platform which supports Raspberry pi and
    
* I had no dev board other than raspberry pi cause
    
* I was poor
    

> ### Communication between things

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In this particular project, the things were two, and they were :

* Raspberry pi + LED connected to it
    
* web app to fire commands
    

I was looking for some kinda glue to stick them both together so that they could start communicating via messages. That was the very basic plan but before hitting google I thought to myself, what if we could use the HTTP protocol to enable the communication? I was familiar with some of the networking stuff, so I picked up my raspberry pi and installed an apache server, and coded a Lil `.py` script to control the led on the pi connected via GPIO.

The idea was to deploy my web app onto the raspberry pi, on doing so I could write a script onto the backend of the web app to directly control the LED via commands coming from the frontend.

![server-browser-relationship.webp](https://cdn.hashnode.com/res/hashnode/image/upload/v1660151662142/L-zytCohL.webp align="left")

I ended up not applying the HTTP protocol and began research. Then I found the MQTT protocol and this time I'm using it.

> ### MQTT test

---

So I wrote the `.py` script on two different files. One for the `publish.py` and the other`subscribe.py`. I ran both scripts using two separate terminals. the `publish.py` file was responsible to publish a msg into the broker and `subscribe.py` was to subscribe. The broker is the central MQTT server which is stateless.

As I published a msg from one terminal, immediately i could see the msg appearing on the other terminal. I was so happy that I took that laptop that day and showed it to my whole family.

![annebell-dogger-iX16iOAQ_lw-unsplash.jpg](https://cdn.hashnode.com/res/hashnode/image/upload/v1660153584066/TeKeDNpzY.jpg align="left")

> ### Way to fire commands

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Here comes the juicy stuff. MQTT demo was working flawlessly, now there was the challenge to code `UI` and get command from there and `POST` to backend. I chose `Express+Node` setup at the backend with no database involved. The plan was to make it less complicated. On the frontend side, i used simple `HTML+CSS`.

The web app is ready, time was to add MQTT flavor to the backend to communicate via a broker. Thus i used the npm package called also `mqtt`. Glued everything together and landed with this beast...

[Web-App](https://led-iot.herokuapp.com/)

![Web-App](https://cdn.hashnode.com/res/hashnode/image/upload/v1660155418861/qzzTH67R1.png align="center")

> ### Pi setup

---

On the PI I modified the `subscribe.py` file and interfaced it with a GPIO pin for controlling the LED attached to it.

```plaintext

import paho.mqtt.client as mqtt
import time
import RPi.GPIO as GPIO

#setmode
GPIO.setmode(GPIO.BCM)

#pin_setup for led.

GPIO.setup(4,GPIO.OUT)

def on_message(client, userdata, message):
	msg = str(message.payload.decode("utf-8"))
	if(msg == "on" or msg=="ON" or msg=="On"):
		GPIO.output(4, GPIO.HIGH)
	elif(msg == "off" or msg=="OFF" or msg=="Off"):
		GPIO.output(4, GPIO.LOW)
	print("received message: " ,str(message.payload.decode("utf-8")))

mqttBroker ="broker.hivemq.com"

client = mqtt.Client("internet")
client.connect(mqttBroker) 
#Loop_Start
client.loop_start()

client.subscribe("internet")
client.on_message=on_message 

time.sleep(90000)
#Loop_End
client.loop_stop()
```

> ### Zoom out a Lil bit

---

I just finished the three major parts of the project :

* Web-App
    
* MQTT broker
    
* Pi script
    

If we tryna understand what's really going on under the hood then we need to step back zoom out a Lil bit and see the bigger picture. I won't explain you in the text but on looking at the below image you'll get what i wanna explain.

![MQTT Broker.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1660156679467/CdscTzmZY.png align="left")

> > Get the `GitHub` repo : [Github](https://github.com/Blaize15/iot-led/tree/master)

> > I made a video `documentary` on this project : [Documentary](https://www.linkedin.com/feed/update/urn:li:activity:6937459206606204928/)