© System Cowboy 2000
Email: Syscowboy@digital-rebels.de

Hey people, I was just sitting in another dull German lesson (No offences to German people) when my mind started to wonder, as it usually does in school. I started to think wouldn't it be cool to kill the school phone system, why? well I don't know but German kind of makes me feel like destroying stuff. Any way, I eventually came up with this: Because I didn't wont to be anywhere near the device when it stated working it has a small timer circuit in it but don't worry this is very simple to make and it can be allot of fun. I will start with the circuit diagram and then move on to explanation later. So here we go.

 

You will need:

1000uf Capacitor
210K Resistor (You can use a variable resistor so that you can adjust the amount of time it takes to run)
16K Resistor
555 Timer chip and holder
Switch
9 Volt battery holder
9 Volt battery
Bits of wire
Strip board
Soldering iron

The following diagram is what my circuit looked like when I finished it, I think most of you people will make it allot neater. (This is the timer circuit)

Right, did you understand that? well if not mail me and I'll try sort it out for you. This is about a 4 minute timer. I would just like to point out I did not make up this circuit I got it from some electronic mag years ago. This is fairly small once built so it is easy to hide, it's also very cheap and it also very useful for many other projects e.g. Bomb timers and I bet you can think of many other uses.

This is tested in the UK so I don't know if it will work in other countries. This is the easy part, get a phone plug and strip down the wire. Hold the plug so that the metal bits of the plug are facing away from you. You only need 2 of these wires, the one the furthest to the right and the wire next to that (On the plug I used the wire colours where Red and Blue). Connect both the wires on the plug to the device out wires on the timer circuit. That's it you have built it.

 

What does it do?

It annoys everyone, that's what it does. It makes the phones connected to the same line as the circuit will ring like hell and this will go on and on until someone pulls it out of the wall. If someone phones in while this is working the ringing will stop and a normal conversation can be carried out. This could be fixed by adding a relay to answer and then hang up.

If you are from a country other than England then please tell me if you get it working or not.