I see them on the net for $1 ea (+ S&H) and wonder if that's a surplus then it's gone price or can happen again price?
Does it take a full-spec&speed USB host to read a USB keyboard?
As far as I know, the "magic" is inside the keyboard or mouse itself.
The adapter is small, and passive, and there is no chip inside.
I have a mouse, which claims to be "USB/PS2" and comes with it's own green colored passive adapter plug. The mouse itself, recognizes the signals are coming from USB or PS/2 and adapts itself accordingly.
The fact the green passive adapter is bundled with the mouse, is proof the mouse is a dual-protocol type design.
Same with keyboards.
I once disassembled one of those "adapters" and found nothing but a USB plug, a PS2 plug and 4 wires...
There are "real" adapters with a chip inside, but they do cost more than $1.
Hi,
In my experience, if you want to connect an older PS2 keyboard like IBM Model M etc, and you want a PC with Windows to recognize it as a USB keyboard you need an adapter with a chip doing translation.
I'm seeing if there's a cheap way to connect cheap USB keyboards to Arduino as TTL serial.
Keyboards do have a chip but it talks to USB which isn't so simple from what I've been told.
I've seen projects that pin-hack mice chips to let Arduinos read particular mice well.
It is pretty easy with older PS2 keyboards (or mice). I have used it several times in projects.
Or you can use one of these dual-protocol keyboards (PS2 / USB with passive adapter to PS2) - my experience is: connecting it to Arduino (with it's passive PS2 adapter) does not work with every keyboard but with most of them.
For "USB only" keyboards you need an USB host shield or an active USB to PS2 adapter I suppose.
If you find a cheaper solution than (the expensive) USB host shield, let me know, I am really interested. 