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        The following was stolen from internal EXiLED memorandums.
        It is a completed schematic for EXiLED's neat new electronic
        device:  The Shadow Box -  A Hold Button of Your Very Own..
        If you have any questions about this file, please contact its 
        author, Shadowmaster, at 901-685-1608 - ask for Chris Turner.

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                             f r o m    E X i L E D      
     

---------------------------------------------------------------------------
 How to build and use a Shadow Box.
 
 Designed and Written by EXiLED.

PARTS LIST:
             SPDT Miniature PC RELAY (about 9v, 500 ohm)
             DPDT Miniature PC RELAY (about 6v, 500 ohms, 12 mA)
             2000 or so uF electrolytic capacitor
             1 meg resistor
             .01 uF capacitor
             555 timer chip
             2 diodes (1N914)
             10 K resistor
             1 K resistor
             9 volt battery -w- clip
             Pc Board
             4 alligator clips
             some kind of a box (small)
             some 20 or 22 gauge wire to work with.

This has to be put together on a pc-board.  Enough talk, now the schematic:



                         +9v
                          ^
                          |
          +---------------+----+----------------+
          |               |8   |4               |
          |            ------------             |
          /            |          |3            |                  |--|
          \            |          |-------------------->|---+------|\ |
    1 Meg /  R1        |          |             |           |     C| \|
   (1000K)\            |          |             |           -     O|\ |
          |            |   555    |             \           ^     I| \|
          |            |   chip   |        10 K /           |     L|\ |
          |           7|          |             \           +------| \|
          +------------|          |             /           |      |--|
          |           6|          |2            |           |
          +------------|          |-------------+-------+   |      NC
          |            ------------                     |   | +-o   o   o--<
          |             |1  |5          --------o NC    |   | |        TIP #2
          |             |   |           --___           |   | |    NC
        + |             |   |                ---o---+   |   | | o   o   o--<
         ---            |  ---.01 uF                |   |   | | |    RING #2
2000 uF  -^-  C1        |  -^-          --------o-- | --+   | | |
*see note |             |   |                       |       | | |
          |             |   |   +-------|--|C       |       | | |
          |             |   |   |       |\ |O   +---+       | | |
          |             |   |   |       | \|I   |           | | |
          |             |   |   |   +---|--|L   |           | | |
          +-------------+---+-------------------+-----------+ | |
                            |   |   |                         | |
                          ----- |   +-----------+-------------+ |
                           ---  |               |               |
                            -   +--/\/\/\----------+------------+
                         GROUND     4.7K        |  |
                           9V                   |  |
                                                |  +------------< RING #1
                                                |
                                                |
                                                +---------------< TIP #1



        K E Y
        ~~~~~

NC - Normally Closed            --< - Alligator Clip

---
-^-   Capacitor                 ->|-  Diode

 |
 -                              
 ^    Diode   
 |                             
 
--------o
___---o  Contacts on relay.  SPDT
----------o


-/\/\/\-  Resistor


    |
    /
    \     Resistor
    /
    |


Whoa!  Well, the schematic explains almost everything.  It would be
helpful to you if you used one color for the line #1 clips and another
for the line #2 clips.  It will work even if you get the ring and tip
mixed up, but you must get all of the clips on the right line.  But,
to be safe, you could put tags on each clip labeling it RING #1, TIP #2,
ect.

Installation.  Find one of those green posts that are about 3 feet high.
They are everywhere.  Get a socket wrench to open it up.  There will
be (a) row(s) of paired up posts.  Each pair of posts represents a line.
YOU *MUST* KNOW THE NUMBER OF LINE #1.  Sometimes the number is tagged
on to the pair of wires leading up to the posts, if so pick these posts
as your line #1.  Then you can pick any other set of posts for line #2.

Now to the good part.  Use of the the final product.  When you call up
line one from your house it will put line 2 on hold!! This is the 
greatest thing since sliced bread!

The Telco. will undoubtably discover the device after 2 days, so post
the number on your favorite boards so you can abuse it while it is in
service.  With a 2000 uF capacitor and a 1 meg resistor you will
get to hold a call for 50 minutes before it disconnects you.  By 
lowering the value of the resistor and capacitor you can change the 
time to your taste.  The formula for the time is the following:

2*R1    C1              C1 is in microfarads
---- * ----             R1 is in Kohms
100     10              See schematic for location of R1 and C1.
-----------  = Minutes
    60

The time produced by this formula is only approximate.

Well, that is one of the more complicated boxes to build.  But it
is very useful and will pay for itself with its first use.   It
would be wise to remove it before the Telco. finds it so you won't
have to make another, or install it on a line that belongs to a
family that is on vacation (GOOD IDEA) that way you can hold calls
for a REALLY really long time.

Well, there it is.  I hope it saves you a lot of cash.

If you wish to have one built for you.  Leave me E-mail to any EXiLED member.
It won't be more than $15 and hopefully it will only be about $8.
Trust us, it's worth it for this kind of boxing power!  Your very own 
hold button!!

EXiLED - 1994

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