I know Morse code is sometimes used by people with limited use of their hands to interact with their computer. One way is by using a straw connected to a pressure sensor, a so-called sip-n-puff or SNP. I've also read mentions of people with handicaps using it for ham radio purposes. Positive and negative pressure corresponds to dits or dahs, or maybe the other way around. There are several commercial devices, and even headsets that look quite handy, no pun intended.
Reading about this has got me thinking: Is using your hand necessarily superior to using your mouth? Why not hook an SNP up to your keyer instead of a bug? Could you use even use it for QRQ? Are there examples of people doing this successfully on the air?
Our mouths are very agile, and with some practice one can handle very quick and precisely timed breath changes. (In this I speak from my own experience playing fast paced Irish music music on the harmonica.)
One big reason for looking at this in the first place is that I've been troubled by recurring hand pain. Being in possession of a perfectly healthy mouth, I can't help but think "why not use that instead of my hands?" Am I missing some reason not to do it this way? I wouldn't be able to talk while sending, but I would have both hands free.
(If this works well, it might even be an option to practice my QRQ and use this with my computer to replace the keyboard eventually, if my hands keep messing with me.)
EDIT: I got asked how fast I play in the comments. Just walking up and down the scale 500 breath changes per minute is not too hard to sustain. At 600 I keep missing holes and mess up the timing. 400 is easy. It doesn't translate perfectly to Morse characters, but with a keyer 200 cpm = 40 wpm doesn't sound unattainable. 30 wpm even more so. I'm just guessing though! It depends on the hardware and on exactly how reasonable the comparison is.
EDIT2: I've gotten some suggestions for various computer interfaces. Using a computer, and even more units might be possible, but, ideally, I would just have a small two-way switch that I can connect to a keyer or the keyer jack on my portable QRP station.