IoT For Makers

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 . ...

In a previous post, I showed you how to display a variety of non-English languages ​​on an LED matrix. In this post, I will look at displaying colorful text that has been image-processed on the LED, rather than just displaying simple text. The image processing content introduced in this article is related to the previous post and https://opencvcooking.blogspot.com/2019/12/basic-cooking-2-pil-text.html . Outline Text Outline text is the text extracted from the outline of the font as shown in the following figure. gimp and other image editing tools make it easy to create outline text images. Let's see how to make it using PIL. In the previous OpenCV blog, the results of the processing were output to a computer screen or file, but this time to the LED matrix. <Outline text Example> See the previous post on how to handle fonts in PIL. import argparse import time , os from PIL import Image, ImageDraw, ImageFont from rgbmatrix import RGBMatrix, R...

It shouldn't be a problem in English-speaking countries, but some countries need to do some work in order to display their characters on LEDs. I am using DietPi OS installed on Raspberry Pi. And my native language is Korean, not English. In most cases, I use ssh on my PC to work on Raspberry Pi. And since the operating system of the PC is Korean Windows 10, there is no difficulty even if it happens to use Korean in Raspberry Pi. However, if you need to output Hangul(Korean language name) directly from Raspberry Pi, like LED output, you need to do some work. This content can be applied to Chinese and Japanese as well as Korean. Later I will show a sample using these languages. Unicode font To display the native language, you must first obtain a Unicode font that contains the native language. Be Careful : Do not use the font of the Windows operating system without permission. There is a risk of copyright problems. I will use Pan-CJK (China, Japan, Korea) Font made by Adobe an...