• Author: Niculescu Rares-Cosmin
• Email: rares.niculescu@stud.acs.upb.ro
• Master: GMRV
• Source code, video and presentation: https://gitlab.cs.pub.ro/rares.niculescu/iot-rgb_ledbar/-/tree/main/

The inspiration came from the 2014-2018 period when I was a part-time DJ at a club in my hometown. In addition to the DJ equipment, I also had a lighting setup consisting of several RGB LED bars that could be programmed and controlled using a DMX console to create a vibrant atmosphere at the party. Over time, I developed a true hobby for programming the LED bars, elements that are present at any show/party with at least 100 participants.

The purpose of this project is to simulate the behavior of a RGB LEDBAR. The user will be able to interact with the LED bar through a web interface that will change the lighting mode of the LEDs. The LEDs can be manually controlled (the final color will be set using sliders), automatically controlled using specific algorithms for coloring the LEDs, similar to those found in Christmas lights for example, or customized through a schedule created by the user (schedule will be uploaded in a Firebase Database). The automatic mode will provide 4 different lighting possibilities.

• ESP-WROOM-32 - ESP32 Sparrow
• Breadboards - 1 half-breadboard + 1 full breadboard
• Wires - as many as possible
• 1k resistors - 12 of them are necessary in this project
• Common cathode RGB Led - 12 of them are necessary in this project

• Firebase Realtime database - For saving the schedule for the custom mode
• Web Page - a simple Web Page designed to encompass all 3 functionalities. The Web Page is stored in the Flash Memory of the ESP32.
• Arduino IDE alongside the required libraries for ESP32: SPIFFS, WiFi, AsyncTCP, ESPAsyncWebServer, Firebase_ESP_Client

Shortly, the architecture has the classic client-server structure, where http client is the user controlling the ledbar, through the web interface, and the esp32 + “firebase” is the server.

• The ESP32 needs a WiFi connection and the API Key + the RTDB URL.
• Once the setup is complete the user can access the application.
• The serial monitor will output the local IP where the user will need to connect.

• The user will navigate through the simple web interface by choosing the lighting mode.
• In the manual mode the user will control the ledbar through 9 different sliders (since we have 6 individual columns, grouped by 2). Each slider modifies the intensity of a RGB channel.
• In the automatic mode the user will control the ledbar by selecting an individual lighting mode. There are 4 buttons on this page and the user can choose between: “Christmas Mode”, “Running”, “Blinking”, “Full Auto”.
• In the custom mode the user will control the ledbar through an schedule uploaded in the Firebase DB. At first the LEDBAR is completely red and the user must not interact with the Web Page. After the ESP32 downloads the content from DB, the LEDBAR turns green and it's ready to “play” the content. The user will manually trigger the schedule by pressing the “START!” button.

• The web interface is locally stored in the ESP32 SPIFFS.
• Initial State
• 
• Manual Mode
• 
• Auto Mode
• 
• Custom Mode
• 

For starters I set up the environment similar to the demos found in labs 3 and 4. For the Web server part, I used the Async Web Server library and configured it similarly to the “SPIFFS Webserver” demo. In other words, the ESP32 web server displays the control page, and when the user interacts with the elements of the page the browser makes a request on a URL, ESP32 receives the request and parses it and, finally, it sends a PWM signal with the corresponding value to the GPIOs. It will also change some internal parameters. As I mentioned before the web page is stored in the internal memory.

After that I have configured the Firebase Database. I have assigned the API key and the RTDB URL and I have signed up on the firebase.

The main idea of the project is to switch between individual “states”. For example state 1 is for the manual mode, state 2 is for “auto mode - Christmas Mode” and so on. Inside the loop function is where the behavior is altered. For the manual and auto mode the behavior is modified 100% by the “internal code” I have implemented. For the custom mode the ESP32 interrogates the Firebase DB to see if there is any schedule to download. If there is none, the ESP32 will wait until the DB updates or the user changes the lighting mode. If there is any content in the DB, the ESP32 will download the schedule and save it in a local file. Once the download is complete the ESP32 waits for the user to actually trigger the schedule.

• I need a few but consistent libraries for this project and the problem is that these libraries take up a lot of internal space (especially the Firebase_ESP_Client). Therefore the ESP32's internal memory is almost full. An immediate disadvantage is that you cannot upload a very long schedule. But this is a minor problem overall as it can be easily resolved using an SD Card to download the schedule.
• Another useful functionality would be implementing a “music-auto” mode where the behavior would altered by the input from a microphone.
• Hardware challenge: You need a lot of equipment to implement this project (as you can see I've used a lot of wires). Also the ESP32's connections are faulty so you would have to either solder the wires or attach the ESP32 module to a breadboard. But, once the connections are stable, the satisfaction comes immediately.
• A dedicated program where the user can create a schedule more easily. It would be also useful because the user will see the actual behavior before uploading the data to the Firebase DB.

In this project I've managed to implement a small RGB Ledbar with functionalities similar to those available on the market. It is an entertaining tool and a very good initial prototype for light show enthusiasts. Certain refinements and tests need to be done to make the user experience as enjoyable as possible. Overall, I consider the project to be a success.

• https://ocw.cs.pub.ro/courses/iothings/laboratoare/2022/lab3
• https://ocw.cs.pub.ro/courses/iothings/laboratoare/2022/lab4
• https://www.browserstack.com/guide/build-a-website-using-html-css
• https://www.arduino.cc/reference/en/language/functions/random-numbers/randomseed/
• https://arduino.stackexchange.com/questions/32739/how-to-get-current-time-and-date-in-arduino-without-external-source
• https://forum.arduino.cc/t/ledc-libraries/663747/2
• https://www.youtube.com/watch?v=ZIj0aZyng1Q&ab_channel=eurolitevideo