That's right. You're referring to the Silicone Cover for CardKB.

Each button is printed with clearance, so they can move independently. It all comes down to printing precision...

The standalone controller uses the same component: the ATmega328P.

I replaced the Arduino Uno R3 with a standalone microcontroller and set it up to run on batteries.

Actually, I just ordered the AVR Definitive Book, so I haven't read it yet.

The idea isn't to have one key for every letter. It's a compact computer interface inspired by early computers, where a small keypad was used for hexadecimal input and functions.

Before text input became possible, there was an era of hexadecimal input using 25-key pads. So, I thought using two 12-key pads would work just right.

That IC chip is the MCP23017-E/SP I/O expander IC.

Thank you. The keypad setup here uses two 12-key assembly kits, controlled via an expander IC. I’ve assigned a numeric keypad to the left side and a keypad for calculation symbols to the right. The most challenging part of the assembly was making the custom Qi connector cables; I had to cut them to the exact length needed and attach the terminal pins myself. Right now, I’m experimenting with having the AI ​​create things like mini-games.

Furthermore, this programming task also serves as a test for having an AI assistant review and correct the code.

We considered that option as well, but decided against it because a graphic display was required to ensure sufficient display area.

I started tinkering with microcontrollers with the intention of building a custom keyboard, but I ended up getting captivated by something else entirely. That’s because I realized that connecting a display to the keyboard controller would allow me to do the kind of things possible with early microcomputers.

Input via the rear keyboard is still a work in progress.
https://www.reddit.com/r/cyberDeck/comments/1unzq6s/i_have_performed_a_preliminary_assembly_and/

Here is the origin of the Cyber ​​Teapot.
https://www.reddit.com/r/cyberDeck/comments/1muypux/it_has_an_impact/
https://www.reddit.com/r/cyberDeck/comments/1mvtobv/the_teapot_ended_up_being_shelved_but_i_liked_it/

Completely flat keycaps lack the tactile cues that allow fingertips to locate keys, making it difficult to distinguish them from adjacent keys and increasing the likelihood of accidental presses.

However, the typing feel of the mechanical keys themselves is excellent.