Timer

A wind-up timer. It switches the blocks it touches on when you start it, and off when it runs out. It's the first automation in the game.

Crafting

P C P
P R P

P is a Copper Plate, C is a Small Cog and R is Redstone Dust.

Using it

• Sneak-right-click to choose how long a wind lasts: 2, 5, 10 or 20 seconds.
• Right-click to wind it and start it. Everything switchable touching it turns on.
• When it runs out it ticks, and everything touching it turns off.
• Right-click while it's running to stop it early.

It works on any switchable block it's touching: a Clutch, Valve, Damper, Breaker and so on. There's no wiring; whatever it's touching is what it controls.

The catch

A timer doesn't know whether the job is done. It only knows how long you told it to wait. A hammer on a water wheel lands about one blow a second at 8 RPM, and a copper plate takes five blows on a long throw, so 5 seconds is about right. But if your Water Wheel is a bit faster today, or the line takes a bit longer to spin up, the same wind gives a different number of hammer blows. Usually you get plates. Sometimes you get foil.

It's still a big step up from doing it by hand. When you want the machine to stop because the job is done rather than because time ran out, you need sensors and a Controller.

Typical setup

Water wheel → shaft → Clutch with a Timer next to it → Crank Linkage → Mechanical Hammer. Put an ingot on the anvil, wind the timer, and come back to a plate (usually).