[Ladyada] and [pt] had an old keyboard from NeXT, but since it used a custom protocol it wasn’t usable with modern hardware. So they built a custom device to convert the NeXT protocol to USB.

Obviously it merely takes someone getting their hands on his USB stick to compromise security, but it does beat a Post-It under the keyboard any day.

Regular Bluetooth 5.0 connection has a 145Hz polling rate, and connection to up to four devices by holding fn+1, 2, 3, or 4 ...