minecraft-java-editionminecraft-redstone
I have a large flat area covered in pressure plates (30×70) and I was wondering how I might wire them from beneath to detect if a mob or object has touched ANY of them. I guess I could cope with a few deadzones, but preferably the whole grid should fire an output.
Is this even possible?
Thanks,
YM
EDIT: Ideally the system should be expandable to even larger areas.
Yes, they can, which makes them fun to set up traps. Source
It works like this:
The first block gets powered from the pressure plate (or you can power it in some other way), the redstone line immediately takes power from there, so all the pistons go up instantly. After some time the repeater draws power from the block and powers the next block, and so on...
When you step off the pressure plate, the first block no longer powers the redstone line, but all the next blocks still do; the first repeater turns off after some time and the 2nd block is not powered anymore... but the line is powered until the last block loses power.
If the signal is shorter than 4 ticks, this scheme won't work well, but buttons always give a 5-tick pulse and pressure plates' signal lasts at least 5 ticks.
And by the way, I used iron blocks, but these can be any non-transparent blocks,
Or, for a different behavior, use an RS NOR Latch as in this screenshot.
This scheme will keep the pistons up for at least the time it takes the current to go through the repeaters, or for more time if the player keeps standing on the pressure plate.
Best Answer
Step 1:
Place Redstone under each block that will have a pressure plate on it.
The Blue Wool represent ground level. That's where the pressure plates will go. I didn't make mine 70 blocks long because I got lazy and the design works the same for any length. I'll cover width limitations at the end.
Step 2:
Cover the area with Pressure Plates. If mob detection is your goal, use Stone Pressure Plates. If you want to detect any entity, use Wooden Pressure Plates.
Step 3:
Place repeaters along both long edges of your area. After each Repeater, place another Redstone.
As you can see, the Creeper activates the Redstone under the Pressure Plates causing the Repeaters within 15 blocks to activate. Were he to go too far from these repeaters, the repeaters on the opposite side would activate.
Step 4:
To ensure your output signal can make it to wherever you want it, you're going to need a few more repeaters. To be safe, I recommend putting an additional repeater every 15 blocks as shown below.
This will ensure that there is always a repeater within 15 blocks of the original signal. These repeaters are where you want to take your output. Wire them together as you see fit, keeping in mind that distances over 15 blocks will require more repeaters.
Limitations
Width: Since Redstone signal can travel 15 blocks from a power source, 30 blocks wide is exactly the limit on this design. If you want wider than that, your going to have to deal with deadzones.