Project Hub /Audio Displays & Interactive Media/LED Matrix & Cube Displays/LED Dot-Matrix Scrolling Display Using STM32 Controller

Advanced

STM32

Project Specific

3 – 6 Hours

Partial Kit

LED Dot-Matrix Scrolling Display Using STM32 Controller

This project displays text entered from a mobile phone via Bluetooth on an LED dot-matrix scrolling display controlled by an STM32 microcontroller.

Originally published on ElectronicsForU

View original tutorial

Parts You'll Need

This project is sourced from another site, not written by us — this list is our best match of their components against what we stock, not a verified bill of materials. Always check the original blog (linked above) for the actual parts list before buying.

MAX7219-4 Dot Matrix LED Display Module – 4-in-1 Cascaded Panel Rs. 698.00
ESP32 WiFi+Bluetooth CP2102 Development Board Rs. 520.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

We don't carry yet: STM32 Board
Perfboard / Veroboard / Stripboard

Browse all components

How It Works

The LED Dot-Matrix Scrolling Display system functions by coordinating wireless data reception, microcontroller processing, and multiplexed visual output. At the heart of the system is the STM32 Blue Pill development board, powered by an external 5V regulated power supply. When a user inputs text via a mobile phone, the HC-05 Bluetooth module receives the wireless transmission and relays the character string to the STM32 microcontroller using serial communication. The STM32 processes this incoming string, converting the ASCII characters into corresponding bitmapped graphical patterns required by the display. Because driving a dot-matrix grid requires continuous multiplexing and current sinking, the system offloads the direct row and column scanning to the MAX7219 IC integrated into the 1088AS LED dot-matrix display module. The STM32 communicates display data to the MAX7219 using a synchronous serial interface, shifting out column data and intensity commands. As the data updates frame by frame, the text smoothly scrolls across the LED matrix, providing a clear and dynamic visual output powered entirely by the microcontroller's logic and the external 5V rail.

Why Build This

Design and implement a wireless embedded communication interface suitable for assistive medical reminder devices and smart pill dispensers.

Master advanced microcontroller peripherals by integrating serial communication protocols with hardware display drivers.

Real-World Application

Digital clocks at railway stations and airports, public announcement display boards, and wireless notice boards.

Skills You'll Learn

Bluetooth serial communication

SPI/synchronous serial peripheral interface

microcontroller GPIO configuration

LED matrix multiplexing

power regulation and distribution

Safety Precautions

No specific precautions noted for this build — always follow general electronics safety practices.

Technology Tags

STM32

MAX7219

HC-05 BLUETOOTH

LED DOT MATRIX

EMBEDDED SYSTEMS

WIRELESS COMMUNICATION

Frequently Asked Questions

Can I power the STM32 and the LED matrix directly from a computer USB port?

While the STM32 can run on 5V via USB, driving multiple columns of an LED dot-matrix display can draw more current than a standard computer USB port safely supplies. It is recommended to use the dedicated 5V regulated power supply to avoid voltage drops or port shutdowns.

How does the mobile phone communicate with the STM32?

The mobile phone pairs with the HC-05 Bluetooth module, which acts as a wireless serial bridge, forwarding typed text directly to the UART pins of the STM32 microcontroller.

Why is a dedicated driver like the MAX7219 used instead of connecting the LED matrix directly to the STM32 GPIO pins?

An 8x8 dot-matrix display requires 16 pins to drive its rows and columns independently, and direct GPIO driving would overwhelm the microcontroller's current limits and pin count. The MAX7219 handles the multiplexing and current control internally, requiring only a few control lines from the STM32.

Gallery

This page is part of Kitkraft's Project Hub — a curated collection of electronics & robotics projects gathered from the maker community to help students and hobbyists discover and learn to build. Kitkraft does not claim authorship of the original project, and makes no representation as to the accuracy, completeness or safety of third-party source material. The summary and "How It Works" explanation above are AI-generated, rewritten with reference to the original tutorial — not a reproduction of it. Full credit and a direct link to the original source are provided above. If you're the original creator and have a concern about how your work is represented here, please contact us and we'll address it promptly.

Kitkraft Project Hub — curated from the maker community, credited at the source.

PRJ-00705