LastValue 

LastValue.ar(in, diff)

LastValue.kr(in, diff)

output the last value before the input changed more than a threshhold

in input

diff difference threshhold 

d = { arg freq=440; SinOsc.ar(LastValue.ar(freq, 20), 0, 0.2) }.play;

d.set(\freq, 400);

d.set(\freq, 200);

d.set(\freq, 670);

d.set(\freq, 680);

d.set(\freq, 695);

d.free;

return the difference between currrent and the last changed 

(

d = { arg out=0, val=1;

SinOsc.ar(

abs(val - LastValue.kr(val)) * 400 + 200, 

0, 0.2

)

}.play;

)

d.set(\val, 3);

d.set(\val, 2);

d.set(\val, 0.2);

d.set(\val, 1);

d.set(\val, 2);

d.free;