> I would like the effect to be nearly instant, but if it's not instant > that's okay. And I'd like to avoid monitoring a dependent variable like > hw.sensors.acpibat0.power0 and then checking the A/C status every time a > change is detected.
sensors do not update instantly. They are serviced in a loop by a thread. but it happens soon enough. use 'systat sens 1' to watch.