This is a USB steno keyboard PCB for use with Plover. http://www.openstenoproject.org/plover/

It's a relatively easy to assemble if you have basic soldering skills and a hot glue gun.

I like it better than the other DIY or "low-cost" options I found, because:

• The two hands are spaced apart somewhat, but it's still a mono-bloc design (it can rest on your lap). The "number" and "*" keys are duplicated, for comfort.
• It uses 2U keys (a single, long key for two positions), to avoid unnecessary gaps. They still hold well and remain smooth despite the overhang.
• It connects over Gemini PR protocole. No interference with your existing keyboard, even if you have Dvorak re-mapping and funny input methods.
• It's cheap, if you can build it yourself (especially if, like me, you're going to need 2 or 3 for your home and office)

What I don't like about it (look out for a Version 2!):

• It's not wireless. Silly me! Where did I have my head!
• It doesn't have any fancy features like recording your strokes into a memory bank when you're off-line, and then re-playing them when connected.

Here are the assembly instructions: https://youtu.be/82yD0RMeEw8

You'll need:

• 28 mechanical key switches. I've used Gateron KS-9 RGB switches, but most brands should fit. White stem (35g), the force is just right, even when pressing multiple keys together.
• the same number of key caps. I suggest XDA keys (but any should fit), they feel good when pressing 2 keys with the same finger. I bought mine here: https://item.taobao.com/item.htm?sid=654489112097 They're good and they have 2U keys, but you might need help from a Chinese friend.
• a RP2040 microcontroller board. They're the star of the year (2022), so you won't have trouble finding one.
• Some 2.54mm header pins
• a USB cable.

Software: you'll need

• the Micropython image for the RP2040
• Thonny
• main.py and YASK.py from https://github.com/ttempe/YASK