Prepare yourself for the Minecraft Redstone Update, which enables exciting additions such as the Redstone Comparator, a daylight sensor, weighted pressure plate, Nether quartz and ore, more detailed death messages, three settings in smooth lighting, and "many, many bug fixes." Minecraft 1.5, the Redstone Update, hits on Wednesday, March 13.Update 1.5
provides a number of changes to Minecraft
's Redstone, including variable signal strength, the introduction of a new capacitor block with one input and output each, new minecarts and more.
Take a look at the complete pre-release change list below, and grab it directly from Mojang here