A timed switch with Dynamic

Question

I'm trying to make a binary switch that switches after a fixed given interval. Why doesn't the following work:

step = .1;
t = Dynamic[Clock[{0, 5, step}, 5, 1] ]; 
Dynamic[t >=  2]

Answer 1

Note that you've defined t as a Dynamic expression. A relational operator like GreaterEqual (>=) works with numeric expressions like the result of Clock. You could try something like this to get a displayed output that eventually switches from False to True:

step = .1;
Dynamic[{t, t = Clock[{0., 5., step}, 5., 1]; t >= 2}]

Answer 2

I couldn't help thinking about this question even after I voted for billsphere's perfectly satisfactory answer. Finally, I concluded that Trigger would be a better way to implement the requested functionality. It is just as easy to use as Clock and throws in a nice little control panel as a bonus.

With[{dt = 1, tmax = 10, threshold = 4}, 
  Column[{
    Dynamic @ Row[{t, " > ", threshold, " is ", t > threshold}],
    Trigger[Dynamic @ t, {0, tmax, dt}, dt]}]]