wouldn't this be an appropriate use of an arduino/other microcontroller?
The problem with Blue is that it would disturb everyone in my house. I want to be able to hear it through earphones or lower the volume. And I don't like tactile bumps.
Thanks for the suggestion Melvang. Seems a bit complicated.
To avoid the lag, what if we skip the OS layer and have the click sound built into the keyboard itself. Not a physical sound from the mechanics but an electrical one that could optionally have its volume lowered or increased. And you could plug your earphones in to the keyboard if only you wanted to hear it. This way you would have immediate auditory feedback with linear switches. I wouldn't want to try doing this myself so are any keyboards already made that offer this?
With auditory feedback, I could type blindly on Red switches (I mean with my eyes closed).
There have been some that had a speaker in them but I don't have that knowledge, nor am I sure they would even work on a modern machine without further modification. As far as doing this with a new keyboard that might require one that already has a teensy controller and adding some stuff to the firmware but again that is WAY beyond my knowledge. Hasu might be able to help with that though.
is my idea plausible?
raspbery pi with speaker attachment + really small linux distro (or not even a real OS) + firmware to handle usb repeating (faking as a USB hub or something)?
keyboard -> custom box with processor & speaker -> computer
You don't need something as complex as a nano Linux computer.
I think Hasu's converter could do the job. It has just a very cheap Atmega microcontroller, a few passive components around it, and no operating system. it runs a firmware that manages the input from the keyboard, converts it (while interpreting it), and sends new scancodes to an USB output. This firmware is a very smart piece of software, but it is self-contained (no OS, it does just that, but it does it very well).
It has been designed to turn any PS/2 compatible keyboard into a fully programmable keyboard, and as a side benefit I guess the firmware could be modified to emit sounds (maybe just clicks to begin with). The thing is actually almost entirely programmed in C and the source is open. So it could be possible to modify it to emit sounds, that is, if there are still available output lines on the microcontroller. My guess is that there will be at least one available, and this single output line could maybe drive a small speaker or a buzzer.
It is small enough that you can hide it inside most keyboard cases.
If it can be done, there will be no sound delay problem. The firmware reacts in real time to any activity from the keyboard.