The 4xMacropad is a low-cost, open-source hardware 4-key mechanical macro keyboard based on WCH CH552G 8051-compatible USB microcontroller and whose keys can easily be configured from a web browser generating an Arduino sketch.
The CH55x family has been around for several years, and we first wrote about the sub-$2 CH551 Mini development board over 5 years ago, but CH552 variants are also found in more recent hardware such as the Turing Screen Screen information display and another rotary encoder shield with two mechanical keys. The 4xMacropad macro keyboard is another CH522 design, but it’s open-source.
4xMacroPad specifications:
- MCU – WCH CH552G 8051-compatible microcontroller @ 24 MHz with 16KB flash, 1.25KB SRAM
- USB – 1x mini USB port for power
- User input – 4x mechanical key switches with keypads
- Misc – Power LED, Mode switch (A or B), user button
- Power Supply – 5V via mini USB port
The EasyEDA files, documentation, Arduino firmware, and 3D files for the base can be found on GitHub. But as noted in the introduction you don’t even need to code the keys yourself, as Toby Chui (imuselab) – the developer – is hosting a configuration website that generates Arduino code for the keypad, and you can also save and load JSON configuration files if you want to generate Arduino sketches for different keypad layouts.
The total BoM cost for the PCB, components, and 3D printed base is around $3, but imuslab sold a few fully assembled samples on Tindie for $9.99, sadly now out of stock.
Via HackADay
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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From here, buying 4 * (keycap+switch) alone is worth more than 3$, not even including shipping. Wherever I buy those: local store, local internet, aliexpress, ..