We've all seen them, they're welcome mats for outside your front door that make spooky sounds whenever a trick or treater comes knocking. I'm going to show you how to make half of this, so that you can use it for lights, sounds, or some kind of motor powered device (like a skeleton that waves when you step on the plate). Pressure plates work very simply, there are two hard pieces (the plates) with conductive material on each one (aluminum foil) and some kind of spring in between them (sponge). Wires are attached to each piece of conductive material, so when the two plates touch each other (someone steps on it) a circuit can be completed.

Step 1: Gather Materials

You'll need:

  • Two small rectangles of thin plywood (cardboard could work, too)
  • An old sponge
  • Aluminum foil
  • Wire
  • Some kind of adhesive
  • Electrical tape
  • Cutting implements
  • Newspaper to work on (easy clean up)
  • Something to test the circuit with (Like a motor/battery)

Step 2: Assemble Each Plate

*Glue the aluminum foil onto each plate, with a small balled up piece in the middle of each. (The plates can't get close enough together to actually touch)
  • Cut and glue two small squares of sponge on one of them.
  • Tape a wire onto each plate.

Step 3: Attach the Two Plates/Testing

Now, simply glue the plates together, via the sponges. (Aluminum foil on the inside) You're ready to test it out!


Attach one pole of the battery directly to what you're testing on, for the other pole, attach one wire of the pressure plate to the battery, and the other to what you're testing on. Push down on the plate and hope it works!

If it doesn't

Check your connections, do both wires actually touch the contacts of the battery? Do both wires actually touch the contacts on your test subject? Are both wires touching the aluminum foil? Do the foil balls touch each other when the plates are compressed?

If it doesn't stop working

Check and make sure that the aluminum foil balls are constantly touching each other, that's most likely. If that doesn't work, add just a little bit of water onto the sponge, squeeze the sponges to work it in...that should make it a little bit springier.

Have fun!

(I had a video, but you can't tell when the motor is spinning...I'll try and get a better demonstration soon)
is there anyway to make the circuit stay closed after someone steps on the plate. i wanted to put it on the entrance to my room, so when someone walks in the lights turn on and when someone walks out they turn off <br>
How do you hook up sound to the pressure plate?
Hint: Try using a piece of colored tape on the spindle of the motor. Myself and many other people use that to get a visual indicator for when a motor or shaft or basically anything that spins, is spinning.
Can someone please help me? I just finished with the sponge, foil and foil ball. What type of wire? Now where do i put the wire and what do i attach it to? How do i attach it to the battery. And what is that other black thing that the wire is connect to? Im confused. PLZ HELP?!?!!?!
cool sensor, not meaning to advertise or anything (I hate when people do that!) but in my instructable I did something similar, it's like from steps 2 to 10<br/><a href="https://www.instructables.com/id/Ghoul-Grabber/:">https://www.instructables.com/id/Ghoul-Grabber/:</a><br/>
oh and if you want your motor to turn on even if they just step on it really fast then read the rest of my instructable
...how was that not advertising?
Maybe it isn't considered advertsing b/c he didn't pay you to put the ad on your post. :)
I was simply using his terminology, but you're right, it's more so considered spam.
yeah sorry, I'm just mad that other instructables are getting better ratings for pretty much the same thing. I'm also mad that I posted it first and you are getting all of the cool idea and stuff. sorry for spamming
1. Our methods for making it are a lot different. 2. Your instructable was based on the Ghoul special effect, mine was just the pressure plate 3. Your "sensor" could have been explained more clearly...it took me a few read-throughs to understand how it works.
oh man i lolled pretty hard after reading this converbsatibon.
oh man i lolled pretty hard after reading the word "converbsatibon" makes me think of a cinnamon roll doing an action while talking.
cool...I have just the thing! put it in plain sight and have a sign that says &quot;step on me&quot; when they do nothing happens. but then when they turn around there is you in a uber scary costume being all O_O at them. then you yell &quot;WHY DID YOU STEP ON THAT!!&quot; then you chase them. but the cool part is..something does happen. you know to pop you (if you can't see them) by a little light that goes on &quot;behind the scenes&quot; lol. ya kinda stupid but its the first thing that popped into my head. <sup>_</sup><br/>
There's a even simpler design, but you can only use it once and then you have to set it again. So: -open a beer -get two cans of tuna or sardines -have a lunch break -save and flatten the lids -get a nail and something hard -punch holes through one of the lids -attach a wire to each lid -stack the lids with a piece of paper between them -have drank that beer yet? So, one steps on the plates, the burrs punch through the paper and make contact. And you had some tuna/sardines.
Do you know if this could work for <a rel="nofollow" href="https://www.instructables.com/community/Help-Needed/">my land mine?</a> I'm trying to figure out how I'm going to get this to work. <br/>
Yeah, probably.
what to do:start delay when they knock,secretly attach hook to pants after delay ends:GET ME DOWN THIS DAMN HOOK
where did you get the motor? im looking to buy a big motor and a reasonable price
I got it out of those scooters for the disabled...like found in grocery stores.
Where did you get the scooter in the first place?
"...like found in grocery stores." Imma take a guess and say grocery store. ;)
So the store manager just gave him one...?
No, mine was actually from one of those hov-a-rounds that some people have at home...but i figured everyone would know what i meant by the grocery store scooters. My friend and I found two broken ones in a big pile of stuff on trash day a while back.
I would have combined both of them into a rather fast scooter.
Well I did strip it all down, and used the chassis (if that's what you'd call it) to make a three wheeled scooter. Unfortunately, I lost an important piece for connecting the motor to the gears, so I haven't been able to connect the motor to the stripped down version. I also need a 12v battery.
Well I'm sure you could probably go get a new "peice" pretty easily, is it another gear or something like that? And 12v battery? A deep cycle car battery would probably work fine. I'd probably get two and wire them in series to get 24 V and consequently a FAST scooter.
The piece that im missing is just a small piece of plastic that is the right shape to connect the motor to the gear box. ...I couldn't use a 24v battery for a 12v motor, could I?
You probably could push it up to 36v,
i remember trash day one of my favorite days get a load of free junk that comes ahndy later on in other projects
I got a foosball table today...my neighbors had it out on the curb with a "Free - Take it" sign on it. I vacuumed out all the bits of webs and such from the inside, went over it in windex, sanded all the rust off, and now I just need to apply some WD-40 and tighten a few of the people..it'll be like new!
Very cool! I just made one and I rigged it up to some speakers and CD player with CD of screams that i made. When trick-or-treaters step on my door mat, a loud scream will be played. Great instructable!
Thanks =] <br/><br/>My favorite part about instructables is when someone actually uses my project!<br/>
I like it. Simple and effective. You could use it to do all sorts of things, turn on a night light, make a mechanical ghost pop out of the bushes, trigger a land-mine, the sky is the limit!
you could also put both wires on one plate, and aluminum foil on the other to connect the two
Yeah, that would work well, too.
What a snazzy idea!... and just in time for Halloween...

About This Instructable




Bio: I enjoy photography, horticulture and carpentry, and am almost always doing something relating to of those things.
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