{"id":1280,"date":"2023-12-18T14:51:23","date_gmt":"2023-12-18T05:51:23","guid":{"rendered":"https:\/\/se.is.kit.ac.jp\/~o-mizuno\/?p=1280"},"modified":"2023-12-23T09:40:06","modified_gmt":"2023-12-23T00:40:06","slug":"next_keyboard_v1","status":"publish","type":"post","link":"https:\/\/se.is.kit.ac.jp\/~o-mizuno\/2023\/12\/18\/next_keyboard_v1\/","title":{"rendered":"The way to a modified keyboard (Reiwa NeXT keyboard V1)"},"content":{"rendered":"
\nThis article is the 15th day of the advent calendar of Studio Aquatan 2023<\/a>.<\/p>\n

This is Prof. omzn (keyboard modification studies).<\/p>\n

Heisei Version of the NeXT Keyboard<\/h2>\n

When I was still young, in the 2000s, I enjoyed modifying old computers to convert them into the latest PCs.
\nI modified NeXT cube, NeXT station, Macintosh LC II (I think), Mac G4 cube, etc. to make a mini PC.
\nDespite all the hard work, we produced a terrible machine that could not deliver much performance, and would run out of control quickly because of its broken thermal design.
\nI feel bad for the old computers that were sacrificed.<\/p>\n

The NeXT keyboard was something like a Mac-style ADB, but at the time it was just a useless keyboard.
\nThen, young omzn had a flash of inspiration.<\/p>\n

\"\"<\/a><\/p>\n


<\/p>\n

“I think I can get a controller from a junk PS\/2 keyboard lying around here and port it to the NeXT keyboard.”<\/p>\n

He immediately investigated the keyboard mechanism, and found that the keyboard had a key matrix decoder on it, and, unfortunately, the key matrices were all different.<\/p>\n

“I want to make the most of this PS\/2 keyboard I’ve taken apart…”<\/p>\n

Here, omzn had another flash of inspiration.<\/p>\n

“I see, I can rewire the NeXT side to fit this PS\/2 keyboard.”<\/p>\n

Thus was born the Heisei version of the NeXT keyboard.<\/p>\n

\"\"<\/a>
\n
<\/p>\n

I thought it would be OK to use PS\/2, which was the standard at the time, but the era soon gave way to USB, and the NeXT keyboard was used for nearly 20 years with the USB conversion. However, because it was originally a PC\/AT keyboard, it did not work well with Macs, and I had to use it with key-swapping software. In addition, there was no way to access the function keys, which sometimes caused me a great deal of trouble.<\/p>\n

Therefore, for 20 years, I had been thinking, “Someday, I would like to remake this keyboard into a modern keyboard….”<\/p>\n

Reiwa NeXT Keyboard V1<\/h2>\n

In the fall of 2023, Yuyu showed me a keyboard that he had made by himself<\/a>, which ignited my heart, and I started to aim for a complete transition to a self-made keyboard.<\/p>\n

Basically, what we need to do is the same as before, which is to make a matrix decoder that matches the physical matrix. QMK provides an easy mechanism to do this.<\/p>\n

Layout<\/h2>\n

The keyboard looks like a normal keyboard, except that the Function keys are missing, and the backquote is on the numeric keypad, but that’s OK.<\/p>\n

Physical Switches<\/h2>\n

The NeXT keyboard uses ALPS cream axes. The light click feeling is very addictive.
\n(For more information about ALPS axis, please visit this site<\/a>.)<\/p>\n

\"\"<\/a><\/p>\n

Matrix Analysis<\/h2>\n

The above of the following figure shows the matrix of a PS\/2 keyboard that I had posted on my web page 20 years ago.
\nThe matrix was so extravagantly constructed that it would have required 25 matrix pins as it is.
\nI was able to reduce the number of columns by three, since the columns can simply be merged where they do not conflict with each other even if they take ORs (see the bottom of the figure). (bottom of the figure).<\/p>\n

\"\"<\/a><\/p>\n

This still requires 22 GPIOs.
\nThe Pi Pico has 26 GPIOs, so there are still 4 GPIOs left over for this application. We can increase the number of functions by allocating them to LED driving and I2C.<\/p>\n

Hardware creation<\/h2>\n

Put Pi Pico on the board.<\/h3>\n

Cut the razor cable connected to the PS\/2 controller, and connect it to Pi Pico’s GPIOs.
\nThis is the first prototype, so we soldered the cable as it is, but it would be better to make the cable removable with a socket.<\/p>\n

\"\"<\/a><\/p>\n


<\/p>\n

Install the USB terminal<\/h3>\n

3D print the base of the Pi Pico and make the USB port. The photo shows the prototype in red, but the final model will be in black.<\/p>\n

\"\"<\/a><\/p>\n


<\/p>\n

The final shape looks like this. Compared to before modification, it looks much cleaner now that the extra board is gone.<\/p>\n

\"\"<\/a>
\n
<\/p>\n

Configuration of QMK<\/h2>\n

Configuration of the keyboard<\/h3>\n
    \n
  • Define MATRIX_HAS_GHOST for a matrix without diodes, like this keyboard.<\/li>\n
  • The LED of CapsLock is controlled by GP0.<\/li>\n<\/ul>\n