$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$ Blue Box Plans.. $
$ $
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$ THIS FILE WILL EXPLAIN THE $
$ CONSTRUCTION, TROUBLESHOOTING, AND $
$ ADJUSTMENT OF A BLUE BOX. $
$ $
$ $
$ $
$ WE ALL KNOW THAT THE TOUCH TONE $
$ FREQUENCIES ARE COMPOSED OF 2 TONES $
$ (2 DIFFERENT FREQS.) SO THAT IS THE $
$ REASON WHY WE HAVE 2 VCO'S (VOLTAGE $
$ CONTROLLED OSCILATORS). WE'LL CALL $
$ THEM VCO#1 AND VCO#2. IF YOU HAVE $
$ NOTICED VCO#1 AND VCO#2 ARE EXACTLY $
$ THE SAME TYPE OF CIRCUITS. THAT IS $
$ WHY ONLY 1 WAS DRAWN. BUT REMEMBER $
$ THAT WHATEVER GOES FOR VCO#1 ALSO $
$ GOES FOR VCO#2. BOTH VCO'S ARE $
$ COMPOSED OF A HANDFULL OF PART. ONE $
$ CHIP, TWO CAPACITORS, 2 RESISTORS $
$ AND FIVE POTENTIOMETERS. ALL OF $
$ THIS WILL GIVE YOU (WN PROPERLY $
$ CALIBRATED) ONE OF THE FREQENCIES $
$ NECESSARY (THE OTHER ONE WILL COME $
$ FROM VCO#2) FOR THE OPERATION OF $
$ THE BLUE BOX. BOTH OF THESE FREQS. $
$ WILL BE MIXED IN THE SPEAKER TO $
$ FORM THE REQUIRED TONE. $
$ $
$ $
$ THIS IS ONE OF THE MOST $
$ SOPHISTICATED DESIGNS I HAVE EVER $
$ MADE. WHY?. BECAUSE OTHER DESIGNS $
$ WILL DRAIN THE BATTERY AFTER 10 $
$ CALLS. THIS DESIGN WILL MAKE THEM $
$ LAST 10 MONTHS!!!!!!. BUT NEVER THE $
$ LESS, DON'T FORGET TO PUT IN A $
$ SWITCH FOR ON AND OFF. OK LET'S $
$ BUILD THE TWO VCO'S AND CALIBRATE $
$ THE UNIT BEFORE WE GET TO THE $
$ KEYBOARD CONSTRUCTION. $
$ $
< >
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
!
VCO CONSTRUCTION !
=== ============ !
!
TOOLS REQUIRED !
----- -------- !
!
1 OCILLISCOPE(OPTIONAL BUT NOT REQ) !
1 FREQ. COUNTER (REQUIRED) !
1 VOLT METER " " " !
ELECTRONICS TOOLS (PLIERS,DRLL, !
SCREWDRIVERS, ETC.) !
!
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
< >
......................................
.
------------- .
! $-PARTS-$ ! .
------------- .
.
R1 1.5K RESISTOR 5% .
R2 1K RESISTOR 5% .
C1 .1UF ELECTROLYTIC CAPACITOR 16VDC.
C2 .01UF " " (MYLQR)16VDC.
IC1 2207 VCO CHIP BY EXAR ELECTRONICS.
REMEMBER THE ABOVE ONLY SAYS .
VCO#1 BUT THE SAME IS FOR VCO#2 .
R3-R4 150 OHM RESISTORS 5% .
C3-C4 .1 UF ELECTROLITIC CAPACITOR .
10VDC .
P1-P10 200K TRIMMER POT - 20 TURNS .
DIODES USED IN THE KEYBOARD .
ARE 1N914 TYPE (40 OF THEM) & .
13 SWITCHES FOR THE KEYBOARD .
SPST MOMENTARY. .
SPKR=YOU CAN USE A TELEPHONE SPEAKER.
FOR THIS (IT WORKS BEST) BUT .
REMEMBER TO TAKE OUT THE DIODE .
THAT IS CONNECTED ACCROSS IT. .
.
......................................
< >
***************************************
* *
* --------------------- *
* ! *IMPORTANT NOTES* ! *
* --------------------- *
* *
* 1. DO NOT USE ANYTHING ELSE OTHER *
* THAN A MYLAR CAPACITOR FOR C2. *
* 2. PINS 10,9,8 SHOULD BE TIED *
* TOGETHER AND BE LEFT FLOATING. *
* 3. ALL RESISTORS SHOULD BE 5%! *
* NOTHING ELSE! *
* 4. A TELEPHONE SPEAKER GIVES THE *
* BEST RESULTS. *
* *
***************************************
< >
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% -------------------- %
% ! TROUBLE SHOOTING ! %
% -------------------- %
% %
% BY NOW YOU SHOULD HAVE CONSTRUCTED%
% THE TWO VCO'S ON A BREAD BOARD OR %
% ANYTHING THAT PLEASES YOU. %
% CHECK FOR COLD SOLDER JOINTS, BROKEN%
% WIRES, POLARITY OF THE BATTERY, ETC.%
% BEFORE WE APPLY POWER TO THE VCO'S %
% WE HAVE TO ADJUST THE POTS FOR THEIR%
% HALF WAY TRAVEL POINT. THIS IS DONE %
% BY TURNING THEM 21 TURNS TO THE %
% RIGHT AND THEN 10 TURNS TO THE LEFT.%
% DO THE SAME FOR ALL TEN OF THEM. %
% %
%-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-%
% %
% NOW APPLY POWER TO THE UNIT CHECK %
% TO SEE THATY YOU HAVE POWER IN THE %
% CHIPS BY PUTTING THE POSITIVE LEAD %
% OF YOUR VOLT METER ON PIN 7 AND THE %
% NEGATIVE LEAD ON PIN 12. IF YOU DO %
% NOT HAVE ANYTHING THERE TURN OFF %
% THE UNIT AND RECHECK THE WIRING. %
% %
%-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-%
% %
% WHEN YOU GET THE RIGHT VOLTAGES %
% ON THE CHIPS, CONNECT A DIODE TO A %
% PIECE OF WIRE (LOOK AT FIG. 2 FOR %
% THE ORIENTATION OF THE DIODE) FROM %
% GROUND TO ANY POT AT POINT T (LOOK %
% CAREFULLY AT THE SCHEMATIC FOR %
% POINT T IT IS LABELED T1-T10 FOR %
% ALL POTS). YOU SHOULD BE ABLE TO %
% HEAR A TONE, IF NOT DISCONNECT THE %
% LEAD AND PLACE THE SPEAKER CLOSE TO %
% YOUR EAR AND IF YOU HEAR A %
% CHIRP-LIKE SOUND, THIS MEA^S THAT %
% THE TWO VCO'S ARE WORKING IF YOU %
% DON'T, IT MEANS THAT EITHER ONE OR %
% BOTH OF THE VCO'S ARE DEAD. SO IN %
% THIS CASE IT IS ALWAYS GOOD TO HAVE %
% AN OCILLOSCOPE ON HAND. %
% DISCONNECT THE SPEAKER FROM THE %
% CIRCUIT AND HOOK THE OCILLISCOPE TO %
% 1 OF THE LEADS OF THE SPEAKER & THE %
% GROUND FROM THE SCOPE TO THE GROUND %
% OF THE BATTERY. CONNECT AGAIN THE %
% GROUND LEAD WITH THE DIODE CONNECTED%
% TO IT FROM GROUND TO ANY POT ON THE %
% VCO THAT YOU ARE CHECKING AND YOU %
% SHOULD SEE A TRIANGLE WAVE IF NOT %
% TURN THE POT IN WHICH YOU ARE %
% APPLYING THE GROUND TO UNTIL YOU SEE%
% IT. WHEN YOU DO SEE IT DO THE THE %
% SAME FOR THE OTHER VCO TO MAKE SURE %
% IT IS WORKING. (AMPLITUDE IS ABOUT %
% 2VAC). WHEN YOU GET THE TWO VCO'S %
% WORKING YOU ARE SET FOR THE %
% ADJUSTMENT OF THE INDIVIDUALS POTS. %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
< >
:::::::::::::::::::::::::::::::::::::::
: :
: -------------- :
: ! ADJUSTMENT ! :
: -------------- :
: :
: DISCONNECT THE SPEAKER FROM THE :
: CIRCUIT AND CONNECT A FREQ. COUNTER :
: (THE POSITIVE LEAD OF THE COUNTER TO:
: ONE OF THE SPEAKERS LEADS THAT :
: BELONGS TO VCO#1 OR CONNECT IT TO :
: PIN 14). :
: :
:-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-:
: :
: CONNECT THE NEGATIVE LEAD TO THE :
: BATTERY NEGATIVE AND CONNECT THE :
: JUMPER LEAD WITH THE DIODE FROM :
: GROUND TO POT NUMBER 1.T1. :
: ( THE FIRST POT NUMBER 1 POINT T1) :
: IF YOU GOT IT WORKING YOU SHOULD :
: HEAR A TONE AND GET A READING ON :
: THE COUNTER. ADJUST THE POT FOR A :
: FREQ. OF 1700HZ AND CONTINUE DOING :
: THE SAME FOR POTS 2-5 EXCEPT THAT :
: THEY GET DIFFERENTS FREQS. WHICH ARE:
: :
: $ $ :
: $ P1= 1700HZ $ :
: $ P2= 1300HZ $ :
: $ P3= 1100HZ $ :
: $ P4= 900HZ $ :
: $ P5= 1500HZ $ :
: $ $ :
: :
: NOW DISCONNECT THE FREQ. COUNTER :
: FROM THE SPEAKER LEAD OF VCO#1 OR :
: FROM PIN 14 (WHICH EVER YOU HAD IT :
: ATTACHED TO AT THE BEGINNING) AND :
: CONNECT IT TO THE SPEAKER LEAD OF :
: VCO#2 OR TO PIN 14 OF VCO#2 AND :
: MAKE THE SAME ADJUSTMENTS TO P6-10. :
: :
: $ $ :
: $ P6= 1100HZ $ :
: $ P7= 700HZ $ :
: $ P8= 900HZ $ :
: $ P9= 2600HZ $ :
: $ P10= 1500HZ $ :
: $ $ :
: :
: WHEN YOU FINISH DOING ALL OF THE :
: POTS GO BACK AND RE-CHECK THEM. :
: :
:::::::::::::::::::::::::::::::::::::::
< >
<!><!><!><!><!><!><!><!><!><!><!><!><!>
< >
< ------------ >
< ! KEYBOARD ! >
< ------------ >
< >
< IF YOU LOOK AT FIG-2 YOU WILL SEE >
< THAT THE KEYS ARE SIMPLE SWITCHES. >
< CONNECTED TO A GROUND AND TWO >
< DIODES ON THE OTHER END. THESE >
< DIODES ARE USED TO SIMPLIFY THE >
< CONSTRUCTION OF THE KEYBOARD >
< BECAUSE OTHERWISE THE DISTRIBUTION >
< OF THE GROUND SIGNAL FOR BOTH VCO'S >
< WOULD HAVE BEEN DONE MECHANICALLY. >
< THE DIODE WILL GO TO VCO#1 AND THE >
< OTHER WILL GO TO VCO#2. FIG-3 SHOWS >
< THE ARRANGEMENT OF THE KEYS ON THE >
< KEYBOARD. >
< >
<-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=->
< >
< BELOW IS A TABLE THAT WILL HELP >
< YOU CONNECT THE KEYS TO THE >
< REQUIRED VCO'S POTS. >
< >
<-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=->
< >
< (-FIG 2-) >
< >
<-----!-----!--------!--------!------->
< ! ! ! ! >
< TO ! TO ! FREQ ! FREQ ! KEY >
< POT ! POT ! OUT: ! OUT: ! >
< ON ! ON ! ! ! >
< VCO1! VCO2! ! ! >
<-----!-----!--------!--------!------->
< 1 ! 06 ! 1700HZ ! 1100HZ ! C >
< 2 ! 10 ! 1300HZ ! 1500HZ ! 0 >
< 1 ! 10 ! 1700HZ ! 1100HZ ! E >
< 4 ! 07 ! 0900HZ ! 0700HZ ! 1 >
< 3 ! 07 ! 1100HZ ! 0700HZ ! 2 >
< 3 ! 08 ! 1100HZ ! 0900HZ ! 3 >
< 2 ! 07 ! 1300HZ ! 0700HZ ! 4 >
< 2 ! 08 ! 1300HZ ! 0900HZ ! 5 >
< 2 ! 06 ! 1300HZ ! 1100HZ ! 6 >
< 5 ! 07 ! 1500HZ ! 0700HZ ! 7 >
< 5 ! 08 ! 1500HZ ! 0900HZ ! 8 >
< 5 ! 06 ! 1500HZ ! 1100HZ ! 9 >
< - ! 09 ! ------ ! 2600HZ ! X >
< ! ! ! ! >
<-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=->
< >
< REMEMBER THAT IN FIG-2 IT'S THE >
< SAME FOR EACH KEY EXCEPT THE "X" >
< KEY, WHICH ONLY TAKES ONE DIODE. >
< >
<!><!><!><!><!><!><!><!><!><!><!><!><!>
< >
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ +
+ AS A FINAL WORD YOU CAN BUILD +
+ THIS IN ANY TYPE OF ENCLOSURE AND +
+ SHOULD NEVER BE USED TO MAKE FREE +
+ CALLS USING THE TELEPHONE LINES, OR +
+ ANYTHING ELSE ILLEGAL. +
+ +
+-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+
