Buttons are small redstone activators made of either one wooden plank or one smooth stone. They are used to activate redstone contraptions that are not activated. They send out a redstone signal that can be sent up to 15 blocks away unless a redstone repeater is used. Buttons are some of the smallest blocks in the game, being smaller than both saplings and slabs. A laid piece of string is the closest comparison that one could make to the button. In Seecret Friday Update 3, during Minecraft Alpha, the stone button was added. The wooden button's first appearance was in 12w34a, and its official release was Minecraft 1.4.2. Buttons are more useful than levers when building Minecart train systems because they are easier to hit, unlike levers. Levers, however, are better for activating powered rails since buttons will only activate for a limited time. Stone Buttons must be pressed, but Wooden buttons can be activated by the shot of a bow or anything else capable of shooting without direct contact. Wooden buttons can be used for archery ranges as they could be used to trigger something such as a redstone lamp to declare a winner.
Buttons are blocks with Opacity. Blocks with Opacity are not "fully complete" blocks or have transparency. For some of these blocks, it may not be possible to place other types of blocks directly onto them. Blocks with Opacity are as follows: Water (Source), Lava (Source), Tall Grass, Oak Sapling, Birch Sapling, Spruce Sapling, Jungle Sapling, Red Mushroom, Brown Mushroom, Red Flower, Dandelion, Crops, Sugar Cane, Cactus, End Portal, Portal, Fire, Sign, Torch, Snow, Air, Enchantment Table, Redstone Torch, Redstone Wire, Button, Pressure Plate, Lever, Rail, Trapdoor, Redstone Repeater, Door, Iron Door, Bed, Cake, Fence, Ladder, Oak Wood Stairs, Spruce Wood Stairs, Jungle Wood Stairs, Birch Wood Stairs, Cobblestone Stairs, Bricks Stairs, Stone Brick Stairs, Nether Brick Stairs, Sandstone Stairs, Quartz Stairs, Stone Slab, Sandstone Slab, Cobblestone Slab, Bricks Slab, Stone Brick Slab, Oak Wood Slab, Jungle Wood Slab, Birch Wood Slab, Spruce Wood Slab, Nether Brick Slab, Quartz Slab, Farmland, Chest, Large Chest, Glowstone, Piston, Sticky Piston, Oak Leaves, Jungle Leaves, Spruce Leaves, Birch Leaves, Glass, and Ice.