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Comment by jhardy54 | Hacker News Reader

Honestly I’ve never tried a 34-key layout, though I’ve seen loads in the keyboard layout DB. Are you using something like Seniply?

Also in case it’s useful: much ink has been spilled about TRRS and its alternatives, but I haven’t found any references to folks using an I2C connector (4-pin JST) instead, which eliminates hotplugging risk without introducing the risks of USB/etc.

I purchased a KB2040 (which has a female I2C connector), a 400mm male-to-male I2C cable, and an I2C GPIO expander, which is slightly cheaper than a second RP2040 on the second hand (though a second KB2040 is cheap anyway). I’m optimistic about using I2C and avoiding TRRS, but wanted to highlight it as an option since I hadn’t seen it mentioned anywhere else.

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If you are interested you can always try it out on your current kb, right?

> Seniply Yes, the idea is the same. I'm using Base layer + 3 other and using one shot for the function keys. Tap dance wouldn't be a problem either, I just prefer one shot.

> trrs cable Interesting idea. Why would you like to avoid TRRS? What are the issues with it? I am thinking for the next version some BLE between the sides as it has low latency, but it's a mere idea for now and more research is needed. (also it would be for a wireless version as it would need batteries anyway)

Yep, I can just avoid using one of the keys, I just haven’t seen many key maps with the sort of popularity that Miryoku has, and I hate the analysis paralysis of trying to decide between 10 comparable keymaps (or trying to build my own from scratch).

The issue with TRRS is that you can easily damage your controller(s?) if they’re powered while the TRRS cable is either unplugged or left in a “not quite 100% plugged in” state, as the metal contacts in the connector create a short (between data and power IIRC?) when mid-way plugged in.

I recently fried a controller this way because I didn’t realize that the TRRS connector had gotten slightly yanked and was ~90% plugged in, creating a short, and the controller has been busted since.

In general the advice is “never plug/unplug TRRS while your keyboard is powered” and “always check to make sure TRRS is fully seated”, but in practice it’s easy to make a mistake that requires replacing your controller (and desoldering it if you didn’t socket it, oops).

I like the T-34 layout[0] - I like how much 'science' (research) did he put in it. An another one is the callum layout[1].

There is an option with QMK to rediscover TRRS cable when it gets disconnected or is plugged after startup, but I see now that that's not the only problem. TRRS is an easy/cheap solution, but a dangerous one if not correct.

[0] - https://www.jonashietala.se/blog/2021/06/03/the-t-34-keyboar... [1] - https://github.com/callum-oakley/qmk_firmware/tree/master/us...

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