Introduction: Bluetooth Controlled LED Matrix !

About: Hi, I'm Nemeen, Electronics Enthusiast! I have seen a huge decline in electronics hobbyist in past few years. I started this channel in order to inspire you to create. Hopefully, you will find something that …

In my previous tutorial, I showed you how to built and 24x6 LED Matrix,

But the only problem with that was we have to upload entire new programme to change the message on the display which can be solved very easily by utilizing an HC - 05 module. So today I will show you how you can make a Bluetooth controlled led matrix.

So let’s get started.

Note: - Before proceeding ahead I'm assuming you have already seen my previous tutorial and know how to built 24x6 LED matrix because in this tutorial we will modify it to work over Bluetooth.

Step 1: Watch the Video !

If you don't want to read all the stuff you can watch my video tutorial

Step 2: Everything We Need

Step 3: Bluetooth Module and Its Problems

To control the matrix using Bluetooth. For that, we will be using HC-05 Bluetooth module but you can also use HC-06 or newer version HM10 they will all work just fine.

To get this module working first we obviously need to connect the power i.e. the 5v and the GND then we can connect the Tx pin of the module to the Rx pin of the Arduino and the Rx pin of the module to the Rx of the Arduino but there is a problem,

The module works on a 3.3v logic level and Arduino works on the 5v logic level this can fry the module but we can solve this problem by simply using a voltage driver network.

Step 4: Voltage Divider Network

A voltage divider network is used to create a reference voltage, it simply consists of two or more resistor in series, each resistor creates a potential drop across it.

If we connect 2.2k and 1k ohm resistor in series and apply 5v across it, the 2.2k resistor it will create the 3.3v voltage drop across it.

Step 5: Soldering !

Then I used a small piece of PCB and added a female header so I can remove the module if needed and added the voltage divider network to it then I extended the connections by using the male headers and the module was ready to be used. Next, I connected the power and connected the Tx pin of the module to the Rx pin of the Arduino and the Rx pin of the module to the Rx of the Arduino and that’s it.

Step 6: Schematic & Program

Now it’s time to upload the new programme,

The new programme is very similar to the old one, we have already defined all the possible dummy data and stored it in a dummy array now here we will scan the incoming data and send it to the new array which will take the data from dummy array.

And Schematic has only an extra HC 05 Module attached, Rest is same.

Step 7: Sending Data From Mobile

Once the programme is uploaded download the Serial Bluetooth terminal app from the play store and open it,

Now go to the menu and select the devices and here you can pair it to your devices.

Then go back and click the connect button and you are ready to go.

Step 8: It Works !

After Successful program upload, and Bluetooth pairing it works!

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