help with css sensors inventory manager?

hi, I'm new here, and although i have a grasp on the logic am much of the syntax of lua, i have done very little actual utility programing. so i decided to try to improve my MFR tree farm. (tekkit) what i want to do is detect when an inventory (specifically, a planter,) has more than one or twi stacks in it, and if it does, send a redstone signal. the problem is, i can't seem to find any examples for using css sensors. the ret of the code could be a simple loop like this:

while inventoryStacks <2 do
    restone.setOutput(back,true)
    sleep(1)
    redstone.setOutput(back,false)
end
[/CODE

am i missing anything? and is there any way to have this continue after i relog on the world? (like some sort of redstone contraption to startup the computer if this is the startup program?)

Css? You mean ocs?