uurg. do this (you don't even need 1.5)
1. place down a sticky piston (not facing up or down)
2. put a block on the sticky face of the piston.
3. place a redstone repeater so that it faces the block in front of the sticky piston
4. on the opposite side of the redstone repeater, wire up some redstone connected from the block to the back of the piston and a dispencer
5. power up the repeater and ur good to go. it should look like this (sorry about redstone glitch. 1.7.2 is buggy)[img]2013-12-28_21.38.13.png[/img]
6. hope it works
best of luck