___________SWAT MAGAZINE ISSUE TWENTY SIX FEBRARY  2000 ____________
/           \___________________________________________/            \
\                     ELECTRONIC TIMER FOR BOMBS                     /
/                           by FiReStOrM                             \
\___________/ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ\____________/


-INTRO

Whatever kind of bomb that you make you need to set it off using a fuse,
but using a length of magnesium isn't always as accurate as you planned.
What you need is an electronic timer, no so sophisticated that the police
bomb squad can't decide which wire to cut, but a simple homemade circuit.

Anyone who has a GSCE in electronics will have probably seen this circuit
before, but never thought of it in this light.  Yes using a simple 555
monostable you can time your bomb to go off leaving between 1sec to 30mins
time to run!  The following circuit can be made easily on matrix board
(solder boards) or it you are really proffesional (& don't mind having
them blown up) you could get someone to make the PCB for you.

-HOW DOES IT WORK?

Basically when you press the switch a capacitor charges up slowly and when
it is full there is an output at PIN 3 on the chip.  This means that if a
fuse is attached, it will burn when the capacitor is full.  You can change
the length of how long the capacitor charges up for, by the value of R2
and the value of the capacitor (bigger capacitor the longer!).  This means
that when the switch is pressed the timer goes tick, tick, tick BOOM!!!

Anyway here it is...


-+-+----+-------------+----+-- +9v
| |    \             |    \
| |    /             |    /
* |    \R1           |    \R2
* |    /             |    /
* |    |   _______   |    |
| | +--|--|1     8|--+    |
| | |  +--|2 555 7|-+     |
+-|-|--|--|3     6|-+-----+
   +-------|4     5|--+    |
     |  |   ŻŻŻŻŻŻŻ   |    |
     | SW1         C1===   |
     |  |             | C2===
     |  |             |    |
-+---+--+-------------+----+-- GND

-EXPLAINATION

+ = A junction in the wire
*** = Fuse wire
R1 = 1K Ohms
C1 = 0.01 uF (uF=microFarads)
SW1 = Push to make switch
GND = Ground
PIN 6&7 are connected

R2 and C2 are connected by the following formula:

T = (1.1(R2*C2))/1000

Where T is the time in seconds, R2 is in Kilo-ohms & C2 in uF.  This roughly
equals:

T = (R2*C2)/1000

Easy values for the circuit are R2=10K & C2=1000uF which gives 10 seconds.
For longer eg mins. R2=1M & C2=1000uF which gives approx. 18 mins

The fuse wire needs to be as thin as you can find, probably the thinness of a
strand of wire from inside multi-stranded wire.  As long as it melts accross
a 9V battery it will do!

All you need to do now is to make it, and decide on the time delay.  I normally
use a variable resistor instead of R2 so that I can vary the resistance and
mess around with how long it times.  To do this you will need to replace the
fuse wire with a LED and resistor (270 Ohms).  When the time is up the LED
will light.  When you have found the right amount of time you need to place a
length of fuse wire between PIN 3 and GND and try it (WARNING THE FUSE SHOULD
BE HOT!!!) if the fuse heats up and goes red it will work, if it doesn't you
need thinner fuse wire.  If it works you can then place the fuse into your bomb,
and hey presto!  Please, please, please test your circuit first as the 555 chip
is very volitile and can go off at any time.  When you test the chip use the
same battery you will use when you actually use it, otherwise it may not melt.

-DISCLAIMER

The information I have supplied is for educational use blah blah blah.  I can not
be in anyway held responsible for anyones misuse of this information.  If you
blow your head up because you have tested it, don't blame me.

-ME

If you have any comments or suggestions:

:o) uk_firestorm@hotmail.com

(No flames please they don't make any difference to people!)

-SHOUTS

A big shout out to SWAT and their readers.
And a big advert for GUINNESS & NEWCASTLE BROON ALE-(My native ale!)
-=Firestarter=- for allowing this to be published
_Smurf_ who inspired me to start carding!
Necrothc a fellow hacker for the North East

-LINKS

If you read last months SWAT mag and want to chip mobile phones you
will need a PIC programmer so check out this site it sells the cheapest
programmers around:
www.geocities.com/PIC_interfaces
For all your hacking tools:
www.cyberarmy.com
IF you missed my web page:
www.geocities.com/pendulum_bob
An amazing hacking prog:
www.bo2k.com
In case you don't know how to IRC:     (4 newbies because I never knew for ages!)
www.mirc.co.uk