Jump to content

  • Curse Sites
Become a Premium Member! Help
Latest News Article

Proximity Detector - Detect If A Player Is Nearby! *Now With Photo Tutorial!*


  • Please log in to reply
186 replies to this topic

#1

Regular Hexahedron

Posted 22 August 2011 - 04:13 AM

I built this smoke machine and was playing around with it's ability to trigger arrow pressure pad detectors. Of course it worked just fine.

But I discovered that smoke from that machine has an interesting property, at least in single player (haven't been able to test it in SMP yet). The smoke only exists when the player is within about 18 blocks. Walk away, the smoke stops. Come closer, the smoke starts.

I discovered that it's possible to fire an arrow at the pressure plate from a distance, but it won't trigger until the player comes near enough to make the smoke start billowing.

I also found that you don't need to shoot the pressure plate itself, it also works if you shoot the side of the block the pressure plate is on (as long as the arrow hits fairly near the top). So it would be easy to have a trap where a player unknowingly activates a dispenser that fires an arrow into the side of the block, thinks nothing happens, then triggers the trap just by walking closer.

Or for less violent purposes, you could use this system to play music on note blocks only when someone walks by without needing them to walk on pressure plates.

The downside is that this requires a lot of arrows to use regularly. But in challenge maps where it's fine to have traps that don't have to infinitely reset, or just in fun impractical gizmos to show off to others, this allows detection of players without them needing to do anything besides get close.

EDIT: Scroll down a bit for the photos!

EDIT: Longhornman99001 figured out a way to use a single arrow forever, apparently without it ever despawning! That makes this affordable even in normal single player maps, no need for hundreds of arrows! In the video he also has a nice diagram explaining my triangulation idea.



Using that discovery I've designed an improved, infinite use, only needs a single arrow ever proximity detector. Here are the pics!

Front shot, showing the piston clock:
Posted Image

Overhead shot, with smoke machine's circuitry in the lower right hand corner:
Posted Image

Action shot showing the gravel mid-fall, the arrow in mid-air about to fall:
Posted Image


This model is extremely cheap and easy to build. The clock is based around a piston and gravel blocks. A NOT gate powers the piston, which pushes up the gravel block, completing a circuit and turning off the NOT gate's torch, retracting the piston, which breaks the circuit and causes the piston to extend again and starting the cycle all over, forever.

A pressure plate is next to the gravel block. Next to the pressure plate is the lava of a smoke machine.

You fire an arrow into the gravel block, right next to the side adjacent to the pressure plate. That's close enough (if you do it right) to activate the plate. When the gravel goes up the arrow also goes up and the plate becomes unpowered. When the gravel goes down the arrow falls down and reactivates the plate.

It does appear that every time the arrow is moved it's 1 minute countdown before vanishing is reset. I left the machine going for half an hour and the arrow didn't go anywhere. So this design does let you use a single arrow forever without needing to replace it!

And of course, the proximity effect still works just fine. The smoke only appears and allows the plate to activate when you're within about 18 blocks.

You could also substitute a burning netherrack block for the smoke machine, which would obviously make this even easier to build. However normal fire produces less smoke, and can take a few seconds to trigger the plate. It's not that reliable. A smoke machine on the other hand produces so many damn particles it instantly triggers the machine when you get near.

Aside from proximity detectors, this is a good way of getting rid of the high arrow cost of any perpetually activate particle effect detector. You could also use this design, minus the smoke machine, as say a rain detector that never needs more than one arrow.

One last thing. You might notice that I added a lever that's connected to both the piston clock and the smoke machine. That's to turn the whole thing off off. When flipped on it makes the piston stay extended and the smoke machine's circuit stop blinking. That's optional though. You can leave the machine without an off switch, or have separate off switches for the piston clock and the smoke machine. The piston clock's circuitry and the smoke machine's circuitry are entirely independent and don't need to be connected to each other.

EDIT: There's a bug that makes the machine stop working that seems to be caused by using a gravity block. Instead of using gravel use a sticky piston and a non-gravity affected block.
To see a list of my redstone inventions check out Regular Hexahedron's Inventorium!

Register or log in to remove.

#2

Skylinerw
    Skylinerw

    Sectional Moderator

  • Sectional Moderator
  • 3595 posts

Posted 22 August 2011 - 05:08 AM

Haha, I just recently found this out as well. Here's a video demonstration of it:



Of course, the dispenser isn't firing directly at the block; was attempting to make a random generator using the unpredictable firing of the arrows. It's not going well.

#3

Regular Hexahedron

Posted 22 August 2011 - 05:27 AM

I think you'd have more luck if you exposed the sides of all the blocks with pressure plates. That way the dispenser could hit either the plate or the side of the block, and you'd basically double (ish) your chances of triggering one.

One thing I was thinking about using this for are devices that only work if the player is standing in a specific spot.

For example, you could have an AND gate that requires two pressure plates to be triggered. They could be far enough apart that only standing in one precise place puts you close enough to each to allow both to activate. Or alternatively, you could make a gate that only activates when no players are inside a certain room.
To see a list of my redstone inventions check out Regular Hexahedron's Inventorium!

#4

Suggexxx
  • Location: Sweden
  • Minecraft: Suggex

Posted 22 August 2011 - 09:11 PM

View PostRegular Hexahedron, on 22 August 2011 - 04:13 AM, said:

I built this smoke machine and was playing around with it's ability to trigger arrow pressure pad detectors. Of course it worked just fine.

But I discovered that smoke from that machine has an interesting property, at least in single player. The smoke only exists when the player is within about 18 blocks. Walk away, the smoke stops. Come closer, the smoke starts.

I discovered that it's possible to fire an arrow at the pressure plate from a distance, but it won't trigger until the player comes near enough to make the smoke start billowing.

I also found that you don't need to shoot the pressure plate itself, it also works if you shoot the side of the block the pressure plate is on (as long as the arrow hits fairly near the top). So it would be easy to have a trap where a player unknowingly activates a dispenser that fires an arrow into the side of the block, thinks nothing happens, then triggers the trap just by walking closer.

Or for less violent purposes, you could use this system to play music on note blocks only when someone walks by without needing them to walk on pressure plates.

The downside is that this requires a lot of arrows to use regularly. But in challenge maps where it's fine to have traps that don't have to infinitely reset, or just in fun impractical gizmos to show off to others, this allows detection of players without them needing to do anything besides get close.
This could be very useful, a circuit that's triggered just by coming close to it, with this, we could make revolutionary things with redstone! Could you upload a .schematics?

*EDIT*

You'll never stop to impress me, wont you?

#5

JosiahIsI
  • Minecraft: JosiahIsI

Posted 22 August 2011 - 11:44 PM

This is a cool idea. But considering it will only work in SSP (:-[) It has very few uses if any.

#6

arnie532
  • Minecraft: arnie532

Posted 22 August 2011 - 11:54 PM

An easier thing to do with the pressure plates being activated by arrows when in this setup would be to use nettherack.

Awhile ago a person announced their discovery of this property and found it had to do with mostly particle effects. Nettherack on fire below your pressure plate is an easy setup. You could do a few things with this, although having that thread would have made describing what he learned easier...
Posted Image

Quote

Anyway have fun being topichitler.

#7

Regular Hexahedron

Posted 22 August 2011 - 11:57 PM

View PostSuggexxx, on 22 August 2011 - 09:11 PM, said:

This could be very useful, a circuit that's triggered just by coming close to it, with this, we could make revolutionary things with redstone! Could you upload a .schematics?

*EDIT*

You'll never stop to impress me, wont you?

Thanks, I find your creations pretty impressive too!

Here are some pictures:

This is an overhead view of the smoke machine. Basically, lava next to water emits smoke whenever it gets updated. That redstone circuit constantly flashes causing the lava to update rapidly and emit smoke non-stop.

I added a lever in order to allow turning off the machine. When it gets flipped on the wire is constantly powered so the lava doesn't update. You could of course set it up to be powered another way, or maybe hook it up to a NOT gate so the smoke machine only turns on when some other device is also on.

Posted Image

Here's a side view. The lava source block is one level higher than the water source block, contained in that dirt ring and falling into a 1x1x1 hole you can't see. The water doesn't spread out of the machine because it's naturally attracted by the adjacent hole. The machine also works just as well if the source blocks are located further away, so you could also turn off the smoke by blocking either the lava or water with a piston flood gate.

Posted Image

The pressure plate just has to go next to the smoking lava:

Posted Image

Then it can be triggered by arrows either hitting the plate or just the side of the block:

Posted Image

A dispenser 1 square away seems to be able to hit the right part of the block with an arrow 100% of the time:

Posted Image

Now here's the smoke turning off with distance effect. I took two photos, one close up so you can see the smoke, the other at the minimum distance where the smoke no longer appears.

Posted Image

Posted Image

If you shoot the side of a block with an arrow while far away (or make a dispenser do it) the pressure plate won't activate until you enter the minimum distance for smoke to appear.
To see a list of my redstone inventions check out Regular Hexahedron's Inventorium!

#8

Darquan
    Darquan

    Lapis Lazuli Collector

  • Members
  • 994 posts

Posted 23 August 2011 - 12:02 AM

Another fundamental building block has been discovered! This is great.
Support the Allocator! Find my inventions such as my pressure plate removal detector on the About Me page of my profile.
I'm still looking for more feedback on my configurable Redstone Gate mod. All gates and common circuits (such as e.g. clocks, edge detectors, latches and Flip-Flops) in a single block.

#9

Bladespirits

Posted 23 August 2011 - 12:04 AM

Best thing in SMP for activating an event when a player is around is using grass growing onto a block to trigger waterflow to update changing directions. Used it quite abit for setting up delayed TNT explosions in enemy bases I stumble across so it blows up when they're nearby. And can hide it all underground just make sure some torches are with it so the grass can grow.

Though the proximity difference is much more precise with the smoke though sadly particle effects are server side so of no use there.

On the plus side with the SMP version of grass growing apparently grass will die when under water in moonlight.. which means you could also make it easy to reset itself. If you wanted to use it for something besides setting off TNT anyway.

#10

Kamil
    Kamil

    Obsidian Miner

  • Members
  • 1279 posts
  • Minecraft: SupePsychoSnipe

Posted 23 August 2011 - 12:16 AM

Is it proven to not work in SMP, or are people just assuming it won't work because it wouldn't make sense?

#11

Regular Hexahedron

Posted 23 August 2011 - 12:22 AM

View PostKamil, on 23 August 2011 - 12:16 AM, said:

Is it proven to not work in SMP, or are people just assuming it won't work because it wouldn't make sense?

I have not had a chance to test it in SMP yet. I'd be grateful if anyone wants to try it out.

I think 3 things need to be tested out there:

1) The smoke machine itself
2) Particle effect/arrow/pressure plate interactions in general
3) Proximity effect with smoke machines
To see a list of my redstone inventions check out Regular Hexahedron's Inventorium!

#12

Regular Hexahedron

Posted 23 August 2011 - 12:24 AM

View PostKamil, on 23 August 2011 - 12:16 AM, said:

Is it proven to not work in SMP, or are people just assuming it won't work because it wouldn't make sense?

I have not had a chance to test it in SMP yet. I'd be grateful if anyone wants to try it out.

I think 3 things need to be tested out there:

1) The smoke machine itself
2) Particle effect/arrow/pressure plate interactions in general
3) Proximity effect with smoke machines

I'm not sure whether it being server side would prevent it from working entirely.
To see a list of my redstone inventions check out Regular Hexahedron's Inventorium!

#13

Skylinerw
    Skylinerw

    Sectional Moderator

  • Sectional Moderator
  • 3595 posts

Posted 23 August 2011 - 12:32 AM

Quote

I have not had a chance to test it in SMP yet. I'd be grateful if anyone wants to try it out.

I think 3 things need to be tested out there:

1) The smoke machine itself
2) Particle effect/arrow/pressure plate interactions in general
3) Proximity effect with smoke machines

I'm not sure whether it being server side would prevent it from working entirely.

Just did it on my private server. Absolutely NOTHING happens when the arrow is fired at the pressure plate. Ah well :(

#14

Johnthebaron

Posted 23 August 2011 - 12:42 AM

Well gentlemen. Today is a monumental achievemnt in redstone.
It seems as though what has been created has endless and many useful posibilites.
A way to detect people from a range without them seeing whats happening may be the best thing ever.
Now myself being a trap maker this fills me with joy. :)
The smoke activation and smoker work. The trigger also seems to work on my smp server.
So today gentlemen. I say good job :D

#15

Skylinerw
    Skylinerw

    Sectional Moderator

  • Sectional Moderator
  • 3595 posts

Posted 23 August 2011 - 12:58 AM

Quote

The trigger also seems to work on my smp server.

Eh? That's strange, mine gave no result at all O.o *is confused*.

#16

Regular Hexahedron

Posted 23 August 2011 - 01:03 AM

View PostJohnthebaron, on 23 August 2011 - 12:42 AM, said:

Well gentlemen. Today is a monumental achievemnt in redstone.
It seems as though what has been created has endless and many useful posibilites.
A way to detect people from a range without them seeing whats happening may be the best thing ever.
Now myself being a trap maker this fills me with joy. :)
The smoke activation and smoker work. The trigger also seems to work on my smp server.
So today gentlemen. I say good job :D

It works on your SMP server? That's great!

Skylinerw, did you try building the smoke machine in single player first? Maybe something was off in your design that stopped it from working.

Cool fact: the smoke machine is very loud up close, it sounds like constant hissing. However the smoke still appears when you're further than you can hear it, allowing you to keep it both unseen and silent.
To see a list of my redstone inventions check out Regular Hexahedron's Inventorium!

#17

Skylinerw
    Skylinerw

    Sectional Moderator

  • Sectional Moderator
  • 3595 posts

Posted 23 August 2011 - 01:12 AM

Quote

Skylinerw, did you try building the smoke machine in single player first? Maybe something was off in your design that stopped it from working.

I used the typical fire under the pressure plate to start. I just tried to use the smoke machine.. I followed it step by step and it's NOT working on my server. It does work in my singleplayer, just not my server O.o

#18

Johnthebaron

Posted 23 August 2011 - 01:15 AM

What are you running your server with?
And any plugins maybe that might be messing it up?

#19

Skylinerw
    Skylinerw

    Sectional Moderator

  • Sectional Moderator
  • 3595 posts

Posted 23 August 2011 - 01:20 AM

Quote

What are you running your server with?
And any plugins maybe that might be messing it up?

Utterly vanilla server, no plugins whatsoever.

#20

TwisTeD_SnakeZ
  • Location: Ireland
  • Minecraft: TwisTeD_SnakeZ

Posted 23 August 2011 - 01:30 AM

Wow this is very useful i think, even if its only for SSP. :)