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Variable-pitched frequency generator -

How to annoy your teachers! -

 Written By -

Captain Quieg 

In the fast paced world of education one often finds oneself with a burning hatred towards one or more teachers or fellow students. This article will describe how to build a little device that will emit a very high frequency that is -extremely- annoying to most people and it will wreck concentration and can cause some nasty headaches.

Parts needed:

R1: 100k ohm Trimmer potentiometer
R2: 47k ohm resistor (5% tolerance)
C1: 4.7 uF Polarized electrolytic capacitor
C2: small disc capacitor (.001 uF or less)
SP: 8 ohm speaker. Piezo buzzers work best but you can use most any speaker for this job.
IC: 555 timer Integrated Circuit.. Available at Radio shack or any decent electronics store


Let's start with a schematic of the device..

!             V+ (9 volts)

! R1       :

V           :


:               :8          :4

:      !------------------!

:     7!                 !3

:------!               !-------------

:      !                  !                  :

:      !       IC       !                 --- /!

\      !                  !                 ! !/ !

/R2    !     (555) ! SPKR  ! !  !

\47k  6!                          !               ! !  !

/   ---!                !                 ! !  !

:   !  !                  !                 ! !\ !

:   ! 2!                 !                 --- \!

:------!               !                  :

:      !------------------!                + :

:                 :1                  C1 ---

:                                       ---

:                 :----- V- (9 volts)    - :

:                                        :

:                                        :

:     ! !C2                           :

:-----! !-------------------------------

! !.001uF                                  :



                                                                 - GND


Now that we have the schematic out of the way we can discuss construction..
It's best to use an 8-pin socket for soldering before you put the IC in.. You
can put it on a small PC board or perfboard.. Use R1 (the potentiometer) to
adjust the frequency from a high whistle to an instant migraine. If you find
that the frequency is not as high as desired use a smaller capacitor for C2.
The Idea here is to bring the frequency just below the highest frequency that
can be perceived by the human ear. You will definitely know when you have
achieved this! Once finished mount it in a project case with an on/off switch
and you're ready.



One particularly nice thing about this device is that if you set it to a high
enough frequency it is almost impossible to locate once hidden.. So once
you've found a suitable location put it anywhere were it can't easily be seen
and turn it on.. Guaranteed results! .. One little problem with this thing
is that some teachers don't seem to hear it (generally older teachers).. but
anyone with a good set of ears will be driven crazy by it!! Including you if
you place it in a room that you are planning to be in for any length of time..
So DON'T. If you have any questions about this thing I'll be happy to answer
inquiries.. Have fun!

::: Captain Quieg :::

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