water-powered fast repeater.
How can I make one of these?
I did not invent this design, I don't recall who did, but I've built dozens of them in my fortresses:
WWWWW
WX^b+
WWWWW
where W is wall, X is a floodgate, ^ is a pressure plate set to trigger at water of depth 5 or greater, b is a single-tile raising bridge, and + is open space.
Connect the pressure plate to the bridge, the floodgate, and whatever you want the repeater to drive.Connect the left side of the machine to an infinite source of water. Optionally use another floodgate or something if you want to be able to turn it off.
When you connect the repeater to a source of water, the water will rush in and trigger the pressure plate. This will cause the bridge to rise, blocking the water inlet, and the floodgate to open. When the floodgate opens, it will cause the water level on the pressure plate to drop below 5. This will cause the pressure plate to untrigger, causing the floodgate to close and the bridge to raise. The cycle will repeat. This will cause bridges, doors, floor hatches, or whatever else you connect it to toggle on/off every 100 steps forever. It will also consume water, which is why you need to hook it up to a river or aquifer or something to keep it running.
or, if you have some power to spend, you can use this design:
# %> #
#^<% #
####_#
The pressure plate reacts to 7/7 water and turns the bottom pump off when triggered, the top pump is always on(or turned on then the plate triggers). the pumps have floors so they don't share power. one 7/7 chunk of water is constantly cycled in this system, and the plate sends both an on and an off signal every 101~103 steps. Requires 30 power if the top is always on, 21 power if the top pump turns off when the bottom one is on.the fast repeater up there actually cycles every 240~245 or so steps because of the reset delay on the pressure plate (100 step delay to raise the bridge and open the flood gate, 40 step delay for the plate to un-trigger, 100 steps for the floodgate to close and bridge to lower.)
--edit--
I think I left something out...