Tag Archives: MAX7219


Arduino Tetris on bi-color LED matrix

Nick Lim has posted a new project on building a simple Arduino Nano driven Tetris using two Bi-color LED Matrix Driver Modules that he has designed and is currently selling on his Tindie store named jollyFactory. These display modules use two MAX7219 chip for driving a bi-color 8×8 LED matrix and are chain-able to expand the size of the LED matrix display as required in your project. Four push switches are used in this project to provide an user interface for navigating and rotating the Tetris blocks. An 8 Ohm speaker is also used in the project to generate an audio tone during the play.

Arduino Tetris game

Arduino Tetris game

Step-by-step guide for making a very simple temperature and humidity meter with 7-segment LED displays

In this blog post, I am providing you step by step instructions to build a very simple temperature and relative humidity meter for indoor use. All you need to build this project are an Arduino Uno or compatible board, a DHT11 sensor, and a MAX7219 based 8-digit serial 7-segment LED display. The temperature is displayed in degree Celsius and relative humidity in percentage.

Temperature and Humidity meter

Temperature and Humidity meter

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Bi-color LED matrix display board with Bluetooth

I shared the details of my single-color 8X40 LED matrix display board project here a few months ago. Here is a nice instructable on making a 7 Bi-color 8×8 LED Matrix Scrolling Text Display with Bluetooth support; which means you can send messages and commands to the display via Bluetooth using a Smart Phone. The author illustrates using an Android-based phone, but any devices capable of sending text messages via Bluetooth would work.

Bi-color LED matrix with Bluetooth support

Bi-color LED matrix with Bluetooth support

The project uses 7 Bi-color 8×8 LED matrices, each controlled by two MAX7219 chips. The beauty of using MAX7219 is they take a lot of work off the micro-controller and simplify the design. Moreover, they can be daisy chained and require only three output pins on the micro-controller for the required SPI-interface. The project is constructed using the Arduino embedded platform. In order to achieve faster speed and better scrolling effect, the author used the chipKit Uno32 board instead of the original Arduino Uno board. A HC-07 Bluetooth module is used for wireless serial communications between the display and the Android Smart Phone.

High-voltage seven segment LED display driver with SPI interface

Seven segment LED displays are known to be resource and power hungry. But because they are visually so charming and readable from a far viewing distance and at a much wider viewing angle as compared to any other electronic displays, they are still hugely popular. The required number of I/O pins to drive the LED segments can be reduced significantly by using an additional dedicated hardware. For example, the MAXIM’s MAX7219 device allows you to interface 8 pieces of seven segment LED modules using only 3 I/O pins of Arduino or any other microcontroller. You can find details on the use of MAX7219 to drive seven segment LED displays in my previous projects 4-digit serial seven segment LED display (SPI7SEGDISP4.40-1R), 8-digit serial seven segment LED display (SPI7SEGDISP8.56-1R), and double-row 4-digit seven segment LED display (SPI7SEGDISP8.56-2R). Since MAX7219 operates at 5V, its output can drive LED segments with forward voltage less than 5V. I have successfully used MAX7219 IC with 1.5″ seven segment LED modules that carry two regular LEDs in series per segment. Inside larger seven segment LED modules, the display segments are made of multiple LEDs connected in series and parallel to provide sufficient light to illuminate the segment, and as such they require a higher forward voltage and more current to operate. Recently, I have designed this display driver board that can be used as a bridge in between larger seven segment LED displays (with segment forward voltage up to 24V) and a 5V microcontroller. On its input side is MAX7219 which receives the display data from the host microcontroller through a 3-wire SPI bus.

Serial driver for large seven segment LED displays

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