Theft Prevention Device for Less Than 10$




Introduction: Theft Prevention Device for Less Than 10$

About: Bilal Ghalib is interested in doing things that surprise him and inspire others. Let's create a future we want to live in together.
Some bum just stole my bike seat. This instructable is the first in a series where I'll try to add electroprotection to my stuff.

Theft is a huge problem and a major irritant. Insurance is a good option when you purchase something you really value but revenge is much much sweeter than a new Ipod. So let's try to create a anti theft device which will electroshock the attempted crook, you know, give him a bit of a jolt. If someone tries to nab a few things that gave him some lightning, maybe it'll make them think twice before grabbing valuables off a park bench.

Basic idea for this iteration:
1) Take the guts from a electroshock pen and amplify the input voltage
2) Replace the Activator Switch with a tilt activated switch, this is brought to you by: Instructables User frank26080115
Frank's Tilt Activated Switch
3) Using conductive tape, continue the connections to the nabbers most likely handholds

That's it, it's simple and all the parts you can pick up locally and will probably cost you in the range of 3-10 dollars.

Here's a video of it in action:

Here's a video of a robot in pain:

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Step 1: Gather Materials and Tools

Get your stuff:
1) Acrylic sheet from the window isle at your hardware store (only necessary if you want a box)
2) Short screws with bolts
3) Washer
4) Aluminum tape from the ducting section of your hardware store
5) Electric Pen you may also find it at your local gag shop
6) Acrylic glue

1) Drill and bits
2) Soldering Iron
3) Hot glue gun

Step 2: Make Tilt Sensor

You'll need Frank's Tilt Activated Switch. Frank has some nice animations and fairly easy instructions on how to make one with some plastic acrylic and a few drill bits.

After building one I realize that it is very important to sand down the inside of the washers as well as the lower base of the screws in order to ensure proper contacts. In picture 2 you can see I just used a dremel to do this, careful the washers and screws get quite hot!

Step 3: Take Apart the Pen

The pen unscrews at both the top and the bottom. Remove the battery and the bottom half is not needed. The top half is composed of a tube glued into the outer shell, you'll need to break this. Grab the inner tube with a pair of pliers, pull at one side till it cracks and then proceed to pull on the opposite side. It should crack again and slide right out.

The coils on the transformer are very thin, keep them safe, don't remove the tape that comes over them.

The coils work like a transformer with the high voltage coming out from the middle tab you see that would normally connect to the metal sleeve of the pen. The nub coming off the top of the transformer goes to the + of the battery and the thick wire goes to the - of the battery.

The idea is that the - side of the transformer will only be activated if the tilt sensor connects the central screw and one of the side bolts which would act as one continuous wire to the negative terminal of the battery.

Step 4: Put It Together:

Solder the + terminal of the battery with the +LV of the transformer [see first picture]

Then solder the -LV of the transformer to the middle bolt's hole. To complete the path the washer must connect one of two places, the bottom screw and the middle screw which will complete the -LV side. Or the top screw and the -LV side. So solder that now by connecting the - terminal of the battery with two wires one going to the top screw and one going to the bottom screw. [see third picture]

If you wanted to can make a nifty little case out of acrylic. Just cut out these dimensions:
2 x 1" x 2.5"
2 x 1" x 3.75"
2 x 2.5" x 3.75"

These measurements worked on my model, be sure to take your own (twice!) before you cut. once you have your pieces lay it out and attach "extension" bits of tape to the HV + and the batteries - terminals [see picture 2]. Remember that the aluminum part of the tape MUST touch the terminal in order for it to count as a connection.

Step 5: Finishing Touches:

Once your box is glued you should take the tabs and fold them over till they're nearly flush with the body. Then next step requires you to fold them over into two broad strips. You want the the aluminum part of the tape to touch the extensions aluminum also. So to do this I trifolded the tape and stuck it to the body of the device with the middle strip. You can check the pictures for step by step directions:

Now that the device is done you can go extend the foil tabs out to the most likely hand holds of an object you'd like to protect. Or you could just toss the entire thing to an unsuspecting victim.

Step 6: Future Iterations:

Here's my idea about a second iteration....

Can you use an amplified darlington array touch sensor to trip the shock device rather than the tilt sensor?
(I tried this and it didn't work at first... I overloaded the triplet with current and they died.)

Now some questions:

Is there a better touch sensor we can use that doesn't share a terminal?

Can we make this much smaller?

What's a better shock element?

Maybe with your help, I can make my dream of electroprotecting my bike a reality!

Be the First to Share


    • 3D Printed Contest

      3D Printed Contest
    • Motor Vehicle Contest

      Motor Vehicle Contest
    • Tiny Speed Challenge

      Tiny Speed Challenge

    15 Discussions


    10 years ago on Step 6

    for that of the bike, i had a similar idea for a car, you could use conductive stripes over the bike structure and put the circuit inside one of the metal tubes


    10 years ago on Introduction

    a camera flash circuit is so much easier to use (in my opinion) and a little tip i picked up from trial and error. I used to put a switch on the high voltage side of the circuit and when I close the circuit it 'welds' the switch in the closed position. Now i put the switch on the battery side of the circuit so there is no high voltage running through it. You can then use any switch for it and not have to get one with a high voltage rating.


    Reply 10 years ago on Introduction

    great idea btw. I've been trying to think of a way to implement this into some of my stuff that I value. Also take a look at my Taser Phone slide show. It's your average camera flash taser but in a mobile phone and with a not so average shock!


    yea theft prevention for under $10 its called a lock. lol but honestly good instructable


    11 years ago on Introduction

    That's awesome man... but pretty massive. Stick a switch in though! Imagine electrocuting yourself while wandering around and dropping your !


    Cool idea, but one concern: Your anti-theft device is based on closing the circuit while the tip sensor is activated. If this is the case, isn't the thing most likely to go off while in someone's hand, namely, in transit to a new location? IE while the thief is running off with the device, the anti-theft kicks in and causes the thief to drop the device...onto whatever unfortunately hard surface it is over at the time like linoleum library floors or concrete sidewalks. Would it be worth it to make the device go off whenever something bridged the gap? Or would that just make for trouble?


    11 years ago on Introduction

    Now I have to make a case for my i-pod, make the aluminum strips super thin hook it up to a camera capacitor and see if people at school will try to steal it and laugh at them. Allot of work.


    Reply 11 years ago on Introduction

    If the aluminium touches the ipod and you send a high voltage pulse IT WILL BREAK!


    11 years ago on Introduction

    I'd use a camera flash instead. (I can't feel those anymore!) Good idea!


    Ha nice job man. One thing i would consider is making the aluminum tape thinner but thick enough and make it go all around the box in some direction to ensure the person is shocked


    11 years ago on Introduction

    nice job. will have to do this on my pod even though its huge and mabey use the pod as a power source


    11 years ago on Introduction

    a friend of mine and i did something similar, only we took apart the pen, inserted the necessary parts into a wrist band, and put an RC car receiver in line, so we had a remote controlled shocker for another friend of ours. it's all good and fun. . . my question is, how do you rig this fun contraption of yours to a bike, ipod, or something else to actually keep someone from stealing it? would you place the electrified tabs onto a common grip spot on a bike? would the bike be insulated from the paint, or would it short?- eh, there's probably enough insulation. . . or is it your intention to move further with this to figure that all out? if so, i can't wait to see the outcome.