I built a 10x6 LED-Matrix with the great RGB LEDs WS2812B. The whole matrix is controlled only by one pin of an Arduino Nano V3.0.
I integrated Bluetooth functionality to change the running text from the smartphone. The housing is made of plywood.

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Parts

I used the following parts in this project (the prices can be different in the future):

60x RGB LED WS2812B (as 1 Meter strip)~ 7 Euro
1x Arduino Nano V3.0 ~ 5 Euro
1x Bluetooth Module HC-05 ~ 5 Euro
1x Power supply 5V 3A~ 10 Euro
1x Adapter for Power Supply (e.g. micro USB)~ 1 Euro
1x Capacitor 1000μF--
1x Resistor 470Ω--
some wires--
Plywood sheets ~ 2 Euro
 Total ~ 30 Euro

Circuit

The electric circuit is pretty simple. I just split the led strip into six parts and connect the ending to each other (see picture below).

Electrical Circuit of led matrix
Picture 1: Electrical Circuit

You can also see the 100μF capacitor and the 470Ω resistor which protect the LEDs. In the original LED matrix I also add a switch to turn off the power, but this is not necessary.

LED matrix partially assembled
Picture 2: LED matrix partially assembled

The housing is made of plywood painted later with black paint.

Code

I use three libraries from Adafruit to control the LEDs:

If you don’t know how to install libraries in the Arduino IDE, you can follow this guide.

I implemented this following seven functions:

  • vertical color gradient from top to bottom
  • square color gradient from inside to outside
  • scrolling text from right to left
  • random Tetris show
  • random snake show
  • colored spiral
  • crossing lines

You can find the whole Arduino source code on my GitHub repository: https://github.com/techniccontroller/LED-Matrix_WS2812B

For changing the text  I wrote a small Android App, but you can probably use any other Bluetooth app too. You just need to send the following string to the Bluetooth module:
newHello World!
to show the text Hello World! on the LED-Matrix.
The first three letters (“new”) will be cut off in the Arduino code.

Here is a nice tutorial on how to write your own app: https://examples.javacodegeeks.com/android/core/bluetooth/bluetoothadapter/android-bluetooth-example/

Picture 3: LED matrix in action
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12 Comments

Preuß · 23/06/2021 at 0:10

Moin moin,
a nice Project!!!
Can i have the sourcecode for make the Android withe own Text and Pictures ???

Best regards from the Heart of Germany
Preuß

    Techniccontroller · 24/06/2021 at 21:27

    Hello Preuß,
    Thank you for your comment. You can find the source code for the App on GitHub: https://github.com/techniccontroller/LED-Matrix_WS2812B/tree/master/android

    It is not the whole Android Studio project but should be enough to build your own app.

      Preuß · 26/06/2021 at 14:09

      Hallo.
      Thanks vor thranswers, but i’m a beginner and learn momently with MIT App Inventor.
      How must i use the src/main, to bild a app???
      Best regards

        Techniccontroller · 26/06/2021 at 14:34

        I never worked with MIT App Inventor but I think following video explains how to build your own Android App with MIT App Inventor to send a text to the bluetooth module HC-05.

        https://www.youtube.com/watch?v=aQcJ4uHdQEA

        Just replace the send text (in the video “1” and “0”) with the the text “newHello World!” to display “Hello World!” on the matrix.

Ravi Gupta · 10/07/2019 at 10:20

I send more than 80 alphabets but approx 50 appears on display how I increase message length

    Techniccontroller · 20/07/2019 at 11:02

    Sorry. I think I cannot help you with that question. 100 Characters should be possible, but I never tested it. I don’t have the matrix anymore so I am not able to investigate this behavior.

Ravi kumar Gupta · 29/07/2018 at 5:10

Thank you for your project
my all problem is solve

Ravi kumar Gupta · 28/07/2018 at 10:41

this is problem is solve

Ravi kumar Gupta · 28/07/2018 at 10:40

hello in this project we send command through bluetooth text is scrolling on pixle but problem is that when power is cut or when we restart the arduino text is not appear
can you solve this problem

Ravi kumar Gupta · 28/07/2018 at 8:56

hi if i want to add more text through bluetooth is it possible to run all the text

Hugo · 20/06/2018 at 12:55

Hello

First of all, congratulate him on the project, excellent tutorial.

I have a problem with the arduino code, I do not have much experience in arduino and I can not find a way to solve it.

I followed the tutorial, with the bookstores of adafruit and the caught one.

But when trying to compile the code I get the following error.

“LEDmatrix_V2: 28: error: ‘matrix’ was not declared in this scope

      matrix.Color (255, 128, 0),

      ^

LEDmatrix_V2: 29: error: ‘matrix’ was not declared in this scope

      matrix.Color (0, 128, 0),

      ^

LEDmatrix_V2: 30: error: ‘matrix’ was not declared in this scope

      matrix.Color (0, 0, 255)

      ^

exit status 1
‘matrix’ was not declared in this scope ”

If you could help me solve it, I would be very grateful.

regards

    Techniccontroller · 23/03/2019 at 20:12

    A bit late, but fixed now on GitHub 🙂

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