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\F4\←L\-R\/'7;\+R\→.\→S   Telephone:
\F1\CMay 1, 1975

Dear Fred:

	Enclosed are the drawings for the optical encoder decoder and
counter cards.   It would be really neat  if you could fit everything
on one long size, double height DEC size card.  That way, there would
be a minimum number of buss wires  outside of the card.  According to
my  count,  that amounts  to 26  DIPS.   The  count  goes as  so.   1-
7400,1-7414,1-7410,1-7404,5-7474,5-8234,8-8284,2-74153, 2-74123.  Now
this may be  too much to expect.  If you feel  that you would like to
make a less dense layout, do so.  This can be done by either going to
a  larger  P.C.  board,  say like  Dave  Bailey  used  with  100  pin
connectors which  can be used for jumpers if  necessary.  Or else you
can put it on  more than one  board, but in that  case the number  of
dips goes  up, as I  have tried to  minimize package count  with this
layout.  Good luck. 

	In another  package, I have enclosed the arm drawings.  These
are the most up to date versions I have at the present  time.  I have
not yet incorporated  some of the design changes  made while you were
here, but will do so  shortly.  In any event,  you should be able  to
get all the necessary info from these.  Please guard these carefully,
as  I would  not like them  to get  duplicated and passed  around too
much.  If you need another set, let me know, and I can supply one.  

	I've  made an  internal  stop  for  joint  #3  and  it  seems
allright.  I have also made a slip  clutch for joint #5, so that if it
hits  it's stop it doesnt loosen or damage  the bevel gear set.  I'll
know shortly whether it works or not. 

	I will be making a decision on the arm interface shortly, and
will let  you know the  verdict. At the price  you and Dave
quoted, I hope that your system will be really good.  I like the idea
of an entirely P.C.  version.  I'm all turned on  to printed circuits
now.  As its  easy to run up a big bill at a commercial P.C. house, I
am still interested in  setting up a facility  at Vicarm.  Could  you
send me  the address of Dynachem,  and possibly a catalog.   You also
mentioned  something  about getting  the  gold plating  solution from
another source.  Give me their name too.  Of course, I would also not
refuse a small bottle or two of some of the hard to come by stuff. 

	Russel has not yet shown  up with your boards.  I talked with
him today.  He says that he will finish things up this weekend and  I
should have the  entire supply by about May  10.  I've aged  about 50
years  in the  past  6 months  worrying about  this  whole operation.
Here's hoping that I'll  survive.  No word from  Tech yet.  Maybe  you
can cay  something to George.   Like ask him  if he needs  a delivery
receipt,  or whatnot.  I assume  that the proper people in  purchasing
or receiving know that the arms arrived there. 

	By the way, how are  they doing?  I hope that  your wiring is
working well.  I  am still a bit dubious about its fatigue life.  Let
me know of any problems please. 

	I cashed your personal  check for $100,  but I would like  to
get something  official for the  $150 paid  to you for  the connector
boards.   I'll think  about how  I want to  do it.   Possibly we will
figure it  all out when  you send  the encoder  board layout and  the

	Dont forget to file your income tax  returns.  Remember, that
extension was just for the federal govt.  Check with Massachusetts as
to their requirements. 

	If Russel  is really  right  this time,  I should  be  around
M.I.T. sometime about the 20th of May.  See you then.\. 


Yours sincerely,