2020/03/15

Font Editor for Paroala Dot Matrix display library

Parola is nice library with various animation function to show texts to dot matrix display with MAX7219 controller. There are excel macro and exe based tool to create your own customized fonts included in library. I’ve also created simple font editor which reads font header file and writes out to header file format. For Windows, use at your own risk. Create new from scratch, or start with font file such as included in sample sketch of Parola library. One font data per font file is supported. Name is font name. Comment is saved as comment in header file. Fixed width will create fixed pitch font. Set Auto for width to …

2020/03/11

Declaration of SoftwareSerial causes build error

With board package ESP8266 newer than 2.5.0, declaration of SoftwareSerial like below causes build error. Above type declaration can be found in sample sketch for Adafruit VC0706 serial jpeg camera. https://github.com/adafruit/Adafruit-VC0706-Serial-Camera-Library/blob/master/examples/Snapshot/Snapshot.ino Resulting error message. To fix this issue, change declaration to below. Latest ESP8266 SoftwareSerial library uses EspSoftwareSerial from Peter Lerup; you can also code like below.

2020/03/01

Show QR code on OLED display with Arduino

There’s QR code library for Arduino released 3 years ago. https://github.com/ricmoo/qrcode/ Well made library, works with less memory of Arduino while supporting QR code versions and error correction levels. You can easily create QR code data with above library and show code to OLED display with u8glib library. Below is sample sketch for showing QR code with “https://programresource.net” text data to OLED display, with inverted B/W on left / right half of screen. Very short and simple sketch which does amazing work.

2020/02/24

Use tiny 64×32 dot OELD display with Arduino / ESP

There are many 128×64 or 128×32 monochrome OLED display out, and recently, I’ve seen tiny 64×32 dot OLED display sold. However, library such as Adafruit SSD1306 does not support this resolution at this time. Either find library which support tiny display, or make modification to library. I’ve modifed Adafruit SSD1306 library (version 2.2.0) to use with 64×32 OLED display. Modifications are 2 part in Adafruit_SSD1306.cpp file. Around line 549 and 888, add / modify for 64×32 resolution. Since I simply replaced code near line 888, this library won’t be compatible with other resolution. Simple Hello World sample sketch. Below includes sample sketch with modified library. Also, I’ve modified ESP_Adafruit_SSD1306 library …

2020/02/23

Show bitmap image on OLED display with Arduino/ESP board (Tool provided)

I2C connection Monochrome OLED display is very handy to use. Easy wiring and various libraries provided, such as Adafruit GFX, u8glib, u8g2lib. Monochrome bitmap can also be displayed. You need to prepare bitmap image and convert to hex data. There are tools you can download, but I couldn’t find one that is easy to use. So, I’ve created easy-to-use tool to convert bmp file to hex data (for Windows). Built with Visual Studio / C++. Use freely, no support, use at your own risk. Simply create bitmap file with MS paintbrush for example, save as 24bit bmp file. Launch tool, drag and drop bmp file to tool. You get hex …

2020/02/18

Stand alone ATMEGA328P-AU blotloader writer

ATMEGA328P-AU is small chip used in Arduino Nano, and chip can be purchased and used for own projects. When designing circuit board, I don’t want to waste space for pattern just to burn bootloader, which is usually only used once for most of the time. I use kit sold from aitendo store in Japan to burn bootloader (sorry, not shipped overseas). http://www.aitendo.com/product/15799 This kit comes with socket for ATMEGA328P-AU and circuit board and some parts. After building kit, connect with Arduino with bootloader burn sketch, then place chip on socket and burn bootloader to ATMEGA328P-AU chip. Since original sketch output result to serial port, I added OLED display so it …

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