[kingmanaz]

Amazing. That seems to be almost exactly what I was thinking of. I would think that the sensor would need to be on one's head, though, particularly if one is trying to achieve the "poise" I was speaking of.

>I can't quite bring myself to add yet another device to my life that needs looking after, charging, etc.

I'm with you there, however, having scoliosis, it's nearly impossible to tell when the posture's going "adrift". The Lumo smartphone integration is a turnoff, but if the device is otherwise simple I might just pick one up.