IoT For Makers

A few days ago I received four P2.5 126x64 RGB LED matrix ordered from AliExpress. In this blog, I will connect four LED Matrixes to create a 256X 128-sized display. Preparations are as follows. Materials Raspberry Pi 4 : 1 P2.5 128X64 RGB LED Matrix : 4 Electrodragon RGB LED Matrix HAT :1 Hub74 cable : 4 LED Power cable:2 5V power supply : 1 <P2.5 128X64 4EA RGB LED Matrix> <hub75 cable    LED power cable  5V Power supply> RGB LED Matrix HAT setup The 126X64 size RGB LED Matrix is ​​mostly 1/32 multiplexed. Be sure to check the manual of the LED matrix you use for exact details. If you're in 1/32 multiplexing mode, you'll need to tweak some of the Electrodragon HAT's jumper settings. <Electrodragon HAT jumper settings for 1/32 multiplexing> And I'm going to use 2 Hub74 sockets at the same time. Therefore, I will connect the HUB 74 sockets P1, P2 of Electro Dragon HAT together to the LED matrix. <Electrodragon HAT HUB 74 socket P1, P2 are connected ...

Do you know TetrisClock? TetrisClock is a WiFi clock made of falling tetris blocks. Runs on an ESP32 with an RGB LED Matrix. <TetrisClock on the RGB LED Matrix by Brian Lough> I'm a big fan of RGB LED matrix and I wrote many posts about RGB LED Matrix in my blog . I like to display the TetrisClock screen using OpenCV on the Raspberry Pi to the RGB LED Matrix. However, the TetrisClock shown in the figure above works on the Arduino family of ESP32 MCUs. I also posted an article implementing TetrisClock on ESP32 at https://iot-for-maker.blogspot.com/2020/04/led-9-rgb-led-matrix-drive-with-esp-32.html . But I wanted to implement this beautiful clock in Raspberry Pi, so I googled hard, but couldn't find any good examples. Eventually, I decided to analyze the code written in C language and implement it in Python and OpenCV. In my blog, which mainly introduces OpenCV, I introduced 2 articles to implement Tetris characters. Creating TetrisClock using OpenCV #1 Creating Tet...

" ESP32  is a series of low-cost, low-power  system on a chip   microcontrollers  with integrated  Wi-Fi  and dual-mode  Bluetooth . The ESP32 series employs a  Tensilica   Xtensa LX6  microprocessor in both dual-core and  single-core  variations and includes built-in antenna switches, RF  balun , power amplifier, low-noise receive amplifier, filters, and power-management modules. ESP32 is created and developed by  Espressif Systems , a Shanghai-based Chinese company, and is manufactured by  TSMC  using their 40 nm process. [2]  It is a successor to the  ESP8266  microcontroller. " <from https://en.wikipedia.org/wiki/ESP32 > ESP32 is a Dual Core MCU The predecessor of ESP32, the ESP8266 has a builtin processor. However due to multitasking involved in updating the WiFi stack, most of the applications use a separate micro-controller for data processing, interfacing sensors ...

So far, many Python examples have been created to use the LED matrix. And most of them worked by using ssh remote access or directly connecting a local monitor and keyboard to the Raspberry Pi. However, there is one major drawback to this type of work. There is no scenario management function. Most LED signboards show multiple sentences or images repeatedly in sequence, depending on the conditions. Therefore, we need a tool to properly run the Python files for controlling our LEDs. A suitable tool for this purpose is Node-RED. Node-RED is a flow-based development tool for visual programming developed originally by IBM for wiring together hardware devices, APIs and online services as part of the Internet of Things . [2] Node-RED provides a web browser -based flow editor, which can be used to create JavaScript functions. Elements of applications can be saved or shared for re-use. The runtime is built on Node.js . The flows created in Node-RED are stored using JSON . ...