sum usb is too expensive ! for 35-40 eu I can buy original Amiga keyboard ! adapter should be cost for 5-10 eur max
These adapters certainly wouldn't be possible for that price. The creator is doing something tricky with the USB stack INSIDE the little device.
That's not easy to do. Add in to that an ability to save user preferences and a bootloader so that you can update the firmware, and I think we're getting a fair bit of tech for cheap.
Looking at the device, it seems to be using a
PIC24FJ64GB002 microcontroller. A very capable 16bit, 16MIPS little controller some crazy capabilities. Even figuring out how to leverage this chip takes skill and time that I'm willing to pay for.
Given that it's also designed to be non blocking, I might have finally found a keyboard adapter that can keep up with my typing speed!