Introduction: Monitor Hack - Security System!

Picture of Monitor Hack - Security System!

That old CRT monitor isn't as worthless as you might think!

Don't throw it away, hack it!

This instructable will show you how to turn that old dusty monitor into a personal electric fence!

WARNING: I shouldn't have to tell anyone working inside a monitor that there is a very real danger of being electrocuted if you touch the wrong thing. (You did unplug it first, right?)

SECOND WARNING: If you have a heart condition or a pace maker, you obviously should steer clear of this hack.

THIRD WARNING: The monitor I used for this hack was a small one. The voltage was quite high, but the current is not enough to harm you. It's enough to get your attention, but could potentially have the same effect as a very powerful stun gun.

Watch the video for the overview:

Step 1: Materials

Picture of Materials

For this hack, you will need:

- One used but working monitor.
(Size doesn't matter, regardless of what SHE says.)

- Some non-insulated wire.
Steel or aluminum will work.

- Some insulated ceramic posts.
Get these at the hardware store in the same section where the electric fences are.

- Some wire mesh.
Chicken wire works fine too.

Step 2: Discharge High Voltage

Picture of Discharge High Voltage

The anode of the flyback transformer could have some residual voltage on it, so you must discharge it to ground first!

Use an alligator clip attached from a long screwdriver to the ground strap on the monitor.

Carefully slide the screwdriver under the anode cup until you touch the center metal clip, or you hear a loud pop. If it's been a while since the monitor was on, there probably won't be any voltage left to discharge.

Once you've done that, it is now safe to remove the anode by squeezing the clip at the base.

WARNING: I shouldn't have to tell anyone working inside a monitor that there is a very real danger of being electrocuted if you touch the wrong thing. (You did unplug it first, right?)

SECOND WARNING: If you have a heart condition or a pace maker, you obviously should steer clear of this hack.

THIRD WARNING: The monitor I used for this hack was a small one. The voltage was quite high, but the current is not enough to harm you. It's enough to get your attention, but could potentially have the same effect as a very powerful stun gun.

Step 3: Wire It Up

Picture of Wire It Up

Wrap a wire tightly around the exposed anode clip, and then tuck it under the CRT straps to keep it from moving.

Feed the wire through a hole in the case, and then put it back together.

Step 4: Run the Wire to the Fence

Picture of Run the Wire to the Fence

Run the wire through the ceramic insulators and connect it to the fence.

You can go a couple hundred feet, if the wire is properly insulated. A color monitor's flyback typically puts out around 30,000 volts, with very low current.

Make sure to put the fence on Styrofoam to insulate it from ground.

Step 5: Turn It on and Test It!

Picture of Turn It on and Test It!

After double-checking your wire, turn on the monitor and test it out.

You'll hear a loud hiss as soon as you turn on the monitor. Use a grounded screwdriver to force it to arc to ground.

Even a small 15" monitor will throw a spark over an inch.

Step 6: Put Stuff in It for Safe Keeping

Picture of Put Stuff in It for Safe Keeping

Now you can carefully put stuff inside the fence for safe keeping:

- Valuable jewels
- Your wallet
- The rest of your imported beer
- Your DVD collection
- Fine wine
- Your piggy bank
- Collectible Barbie
- Hundreds of other things!

(No Barbies, cats or pigs were harmed during the making of this video.)


guysoft (author)2014-10-09

Metacafe is dead, and so is the video. Is there any other source to view it from?

BasementBuilder (author)2013-02-28

I have tested and it arks. My monitor has a built in feature that makes it arc to ground to stop it from damaging important stuff.

BasementBuilder (author)2013-02-27

When I first tried this I heard a zttttttt. for about two seconds. It stopped for two seconds and kept doing that, like it was a cycle. Is that normal or a premature grounding. I have not tried to get an arc from it.

astropharmacist (author)2012-11-22

my home has 220v ac power supply. why would i use monitor? afterall u need ac current to turn that on.

shouldawoulda (author)2011-10-26

I like this explanation! More then easy enough to understand.
Have you ever had the visual experience of about 1600watts running up one arm through your implanted neck plate "titanium" down the other arm and to ground?
I was messing around with a 1600 watt inverter last year cracking water "HHO"
and got a bit careless with excitement, That water instantly became foam, like opening a shook up hot can of beer in the middle of summer in Pheonix Arz!
So I was trying to bring it down a bit on the next try, had a bit to many beers myself and whollah! I saw a bright flash of white cover my eyes, will be a bit more careful now,, blew out the fett arrays and the microprocessor on that inverter, didn't kill me but did make me more cautious and curious,,,12 volt auto battery turned powerful?

Jawa888 (author)2010-01-15

 Is this your cat

shouldawoulda (author)Jawa8882011-10-26

It's not mine, but you could probly get more traffic if you changed your sign too, "Free dog food!"

gaby1st (author)Jawa8882011-06-20

Yup,it is he touch the fence.

sam deluca (author)Jawa8882010-02-16

HA HA HA! That's funny.

makincoolstuff (author)2011-08-29

its funny cos u can just reach over the fence and grab the wine and stuff, but cool instructable

bears0 (author)2011-06-06

i cant find the monitors ground?????

kjbaran (author)2009-10-17

You said that Voltage= the number of electrons flowing in a wire, Current= the speed of those electrons. Isnt it kind of reversed? I always knew that the amperage was the electrical "pressure" like the amount of water flowing in a river. (author)kjbaran2011-05-26

voltage is the pressure, current is the amount. So big amps = big pipe. High Voltage = little pipe w/lots of water.

garet1 (author)2010-02-04

when discharging, if I ground to monitor's ground, does monitor has to be plugged in? If not plugged in, then where the charge will go?

Damnation (author)garet12011-04-25

For anyone reading this wondering the same thing, if you plug in the monitor and try to discharge it, the outlet will pump more electricity into it. Chances are you will melt the screwdriver in the process. Plugging the tv in defeats the whole purpose of discharging.

highvoltageguy (author)2011-04-08

never find insulator cuz im unlucky

nerfinaticRN7 (author)2011-04-04

lol, your cat is in there. People do find them valuable.

Andreus Felipen (author)2011-02-18

Yo are gonna kill yourslef

ltnemo2000 (author)2011-01-12

so i did it and got awesome blue arcs but as soon as I tried welding, my monitor just started squealing and smelling like ozone. no mystical blue smoke. is there a fix?
awesome awesome instructable.

Fireater989 (author)2010-12-04

Wait, so you have your large, clunky monitor sitting next to your fence (or lightning globe is what I'm trying to do) running a wire to it? I can't remove the flyback transformer and build a case or something for it?

Fireater989 (author)2010-12-04

Your video isn't showing up. Neither is the video on your other instructable for the lightning globe:!/
I tried in 3 different browsers

hg341 (author)2010-12-03

stfu he didnt do that and i didnt(nor would i ever) do
and i have 2 cats that i love very much(even thoug 1 piss's everywhere)
BUT i still think that is funny as hell

agis68 (author)2010-10-24

well all was good done till when I show this poor pet circled with electric wire!!! You should shame!

knoxarama (author)2010-03-28

my flyback only gives an arc for about three seconds, goes off, and comes back on for another three seconds. is there a way to make it continuous?

pavalos (author)2009-04-27

My crt monitor goes to sleep mode every 5 seconds.. any recommendations so that is always on??

xproplayer (author)pavalos2009-10-27

monitor settings?

pavalos (author)xproplayer2009-10-28

This cant be monitor settings This is only a monitor  without setup buttons It must be signal detection circuit 

CoolKoon (author)pavalos2010-01-09

I think you can avoid this by bridging two pins on the VGA cable (not sure which ones though :P). I think googling for "VGA pinout" might help.

pavalos (author)CoolKoon2010-01-10

Thanks I will try it

CoolKoon (author)2010-01-09

I think you should put there a warning for anyone who's not familiar with HV that NO LIVING OBJECTS should be left in the cage while it's on (as I'm pretty sure you didn't turn the fence on while your kitty was in there :P). I'd also refrain from putting there anything metallic into it as they could short your fence to the ground immediately when you turn the fence on (i.e. soda cans, knives, especially watches etc.).

legano (author)2009-12-31

n00b - coathanger wire?

lukas1121 (author)2009-05-23

ummm i used a huge old tv i discharged it took that thing off cnt remember what it whas clalled put my wire around one of the leggs and put it back in and then i put the other end of the wire to a cage i couldt find any chicken stuff so i used a regular mouse cage i used styro foam and i turn everything on "click" the power went i turned it on again and tried everything again turned it on and "click" the power went again i turned everything on again and turned the tv on... nothing happened please someone help me with my problem

xproplayer (author)lukas11212009-10-27

um you could be doing a dead short somewhere maybe on the wires way out it hits something causing a short. to test and see if you fried it just hook it up to something and see if it still works if not well then tough luck and try again lol.

daniel.nicholls (author)2009-05-18

For those who are a little new to electronics:
This may do you a lot of harm. To explain: Voltage is the size of the hammer, Current is how fast it is swung.
This means that someone may hit you in the head with a normal hammer (small voltage) but if they swing really hard (big current) it will kill you. If someone swings a hammer the size of the empire state building (big voltage) it makes no difference how slow they swing (really small current) its still going to kill you.
Colour tubes can have in excess of 30 000 Volts and the flyback transformer can be capable of delivering over 0.05A so thats a power of 1500 Watts Peak
A 240V power point supplying 10A only gives you 2400W. So now consider what happens when you stick your fingers in a toaster then think about what the tv power supply could do to you.
The other (and more important) danger is the frequency output of the flyback transformer, they very often go up into the RF frequency range. When you suffer an electric shock from these types of supplies it can give you an RF burn, what that means is that it can burn you not only at the entry and exit but the whole way down the path that the electricity took (read heart, lungs, and any other internal organ you like) this is obviously bad for your health.

Lastly even if that has not made you reconsider be aware of the live shasis found in televisions and if possible use an isolation transformer to protect yourself from electrocution.

Good hack, but extremely ill advised for anyone who does not have experience in this field to try.

btw. I know that the sums used above are not entirely accurate but they illustrate the point of power.

A Big old tv will work right ??

xproplayer (author)lukas11212009-10-27

*insert evil laugh here*

Yes it will

Goodhart (author)daniel.nicholls2009-05-23

30,000 volts may or may not be harmful with low amperage.....another factor in AC current is frequency. I have had 200,000 volts ac at a VHF course through me for about 5 - 6 seconds.....and it hurt like hang (Some HV stun guns are in the 100,000 volt range), and I have had 80,000 volts pounded through me from an ignition coil while someone was starting the car......and although that didn't kill me, if felt like I was being HAMMERED (my chest was leaning against the bumper of the VW at the time), hard, in the chest and hand/arm. Great caution is advised, but there is no need to instill unwarranted fear either.

knoxarama (author)2009-09-29

i just used a grounded wire at the end of my 'safety stick'.

kjbaran (author)knoxarama2009-10-17

your mom grounded my saftey stick. jk. I just bought a 100kv power supply off of ebay for like $60 yesterday. I plan on doing some lifter experiments.

The 4th Doctor (author)2009-10-02

I agree that the single transistor flyback is one of the best beginner voltage supplys but that analogy of yours is rather backwards current is like the amount of electrons and voltage is like the speed/pressure a decent airsoft gun shoots at upwards of 200mph, can give a nasty welt but getting hit by a car going 200mph is quite worse obviously i dont particularly like the saying current kills not voltage because voltage does matter since it determines the amount of current delivered When removing a flyback from a television its really not necessary to use a resistor usually i dont even hear anything and any spark generated would give of a very slight amount of UV and wouldent take a significant amount of material off of a metal screw driver, dont forget about the larger electrolyte capacitors on the tv's control board

juanpy (author)2009-09-10

I'm 1 year away from becoming an engineer, an one thing I know for sure, and that is , that kids, should NOT be playing with flybacks, 20,000 volts, are not a joke, an seriously if you don't know what are you doing, don't do it.

robotguy4 (author)2009-08-31

Wouldn't this be better if, instead of just a fence, you used a mesh dome that opened up?

CameronSS (author)2008-04-16

An 80 pound kid going let's say, ten mph, has 800 footpounds of force behind him.

Footpounds are a measurement of torque. Force is measured in newtons (metric/SI) or pounds (US Customary)

Briguy9 (author)CameronSS2008-08-21

i just got a lesson on joules, and there the same thing as footpounds, sooo, no. footpounds is actually a different way of saying "joules," and joules is a measurement of force and electricity.

Goodhart (author)Briguy92008-09-11

Hmm, where did you read that?

One joule is equal to the work done when a current of one ampere is passed through a resistance of one ohm for one second.

Derin (author)Goodhart2009-05-23

It is also equal to one watt :)

CameronSS (author)Derin2009-05-23

No, it is not. A watt is a unit of power, equal to a joule per second (J/s). It is the amount of power required to do one joule of work each second.

A watt is equal to the current flow (amperes) times the voltage potential (volts), or various other formulas that play around with that basic relationship and Ohm's Law (V=IR).

Zhenghui (author)Goodhart2008-09-21

hey goodhart I've read alt of your comments and you seem to be one of the most knowledgeable on the instr. I am new to electronics and I would need some advice I want to build a L E D sing with a circular continious led lights running around the sign while a center led word flashing at a regular interval and all this one in red and one in yellow the word in the middle would be different in yellow then the one in red and 2 swithches that would control the different colors like one switch for the yellow and one for the red could you please help me please

geeklord (author)Zhenghui2008-10-07

I agree. You do seem to be a pretty knowledgable person.

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