Portable Shopping Cart Locking Force Field OF DOOM

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Introduction: Portable Shopping Cart Locking Force Field OF DOOM

Have you ever been annoyed or even injured by evil sentient shopping cart attacks? well, now you can shop in safety! this belt will stop any hostile shopping cart in it's tracks if it comes within five feet of you! No more bruised ankles! no more threat of cart insurrection!
This life-saving device works by emmiting intense electromagnetic radiation that confuses the shopping cart and makes it think it has reached it's boundaries causing it to lock it's wheels in fear. don't delay, Build one NOW!

Disclaimer:
This is a proof-of-concept for educational purposes only, and may be illegal in some areas. this device also has the potential to really piss off store managers, so please use with discretion. i take no responsibility for the actions of anyone reading this.

You're going to need:
1 db9 female plug
1 db9 male plug
3 feet (roughly) of cat5 cable (or a serial cable)
1 headphone plug/wire
1 mp3 player
1 laptop or good quality recorder

Step 1: Make the Belt...

First, cut a length of cat5 cable so it is long enouth to wrap around your waist (you can make it wrap around twice, if you want, but i didn't), but make it loose so you can work with it.

next get the db9 plugs, headphone plug and your soldering iron.
connect the cat5 cable's wires to the db9 plugs with the following pinouts:

male:
pin: | wire color:
1 Green stripe
2 solid Green
3 Blue stripe
4 solid Orange
5 Headphone jack
6 Brown stripe
7 solid Blue
8 Orange stripe
9 Not connected
the extra brown wire goes to the headphone jack

female:
pin: | wire color:
1 Solid green
2 solid Blue
3 Orange stripe
4 solid Brown
5 Brown stripe
6 Green stripe
7 Blue stripe
8 solid Orange
9 Not connected

Step 2: Go to the Store!

For this step you'll need either a laptop with recording software or a really good voice recorder.
Go to the store and find the cart boundaries. they'll probably be marked with a yellow line. once you found the yellow painted line, look for a thin, black line running parallel. that black line is the actual boundary, beneath it lies a wire emitting the cart-killing signal.

connect the belt to your laptop or voice recorder... actually if you have a telephone mic, use that instead. (it's those little suction cup things you put on the phone. it's just a coil of wire) or, if you're cheap use a solenoid attached to a headphone jack. unmute the microphone in your laptop's sound mixer and turn the volume way up. position the coil/pickup/whatever over the wire until you hear a signal. at the sprawl-mart i went to, the sound was a short chirping sound every half second.
when you hear the sound, record it with your favorite sound recording program. make sure to record it at at least 44100 hz at 16bit. DO NOT SAVE IT AS MP3. save it as an uncompressed wav file.

using your sound editor, do a little noise reduction (if any is needed) and increase the volume.
i lied, you can save it as mp3, but remember, it's a lossy format, meaning you will loose data, so use at least 128kbps and turn off any filters.

once the file is satisfactory, put it on your mp3 player (or whatever. i used a program on my pda-phone)

Step 3: Going In!

It's time to try it out!
put the belt on, and wear a shirt long enough to cover it. plug the belt in to the mp3 player, crank up the volume and put it on repeat. i recomend putting the mp3 player in your pocket. test the range by moving close to a cart until it stops. if they stop, awesome! if they don't, GO OUTSIDE then check for shorts (don't do it in the store!), if there aren't any, your mp3 player isn't loud enough.

Step 4: The Missing Page!!!

Coming soon:
the shopping cart force field OF DOOM version 2.0
Now with amplification, you can keep the hostile sentient shopping carts up to fifteen feet away! Stay tuned!

I haven't had time to solder up an amplifier circuit, yet. (actually, i did, it just doesn't work) if you've just got to have one now, try using a battery powered amplified speaker, and replace the speaker with the belt.

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149 Comments

the shopping carts will hate you :)

What country is this from? I'm in the US and I've only heard preposterous theories about self braking shopping carts.

The shopping carts at HEB in the low-income areas of Houston, TX lock up on you! It was really surprising to push one really fast across the boundary and watch it fall over. haha

i am in us and i have had a shopping cart lock up on me. look for a weird device on one of the wheels it looks innocent but it will brake it fast!

i just built one of these, and im so excited to try it i can hardly breathe... oh well. Amplifiers are very easy, just break open a tv and find an IC with only one side covered in pins, probably starts with "AN" (the # on the front) and look up the schematics online. I built one of these, and it just took an hour for a 3w amp. not amazing, but same principal i guess... T-elospathic

cool, DON'T GET CAUGHT! also, i'm not going anywhere near the very high voltage innards of a cathode ray tv. i've seen a screwdriver weld itself to a tv amid pretty spaks and a very loud crack. i'll just destroy a stereo for the parts.

I Agree, and handling the Cathode Ray Tube in the wrong way and you drop it, it may EXPLOED!! If your going to use parts from a older tv always, always remove the thick red wire that looks like a suction cup (its about half way down the Cathode tube(towards the part you watch CSI: MIAMI on( by removing this wire you let the gases inside the tube to escape))) also for added safety remove the wires at the small end of the tube. And always remember UNPLUG IT FIRST BEFORE OPENING THE CASE!!!

removing the tht (suction cup) will not cause any gasses to escape, in fact, the tube is a vacuum and there is no gas in there. If I had listened to your advice, i'd be in the hospital with arterial fibrelation!

well you would if u either left it plugged in or opened it right away cuz the CRT can still hold energy after sitting unplugged for a few days, 30+ days should be enough time for the power to drain off.

oh and my dad told me there was gases in a CRT, and my dad is known for being incorrect 80% of the time

The CRT is a vacuum. It may not be a perfect vacuum, because of manufacturing error, but it is not filled with gases. Sorry daddy, but this is part of that 80%!

The one that shocked me was unplugged ~5 minutes before electrically assaulting me. The CRT does not hold energy, and the amount of capacitance that the flyback has is likely lower than 5 pF. That's hardly anything. What holds charge are the capacitors that supply/buffer the flyback circuit.

This is a long thread. This is awesome.