[misc.handicap] Reading a thermometer via a computer

DAVE.WILLEY@f7.n125.z1.fidonet.org (DAVE WILLEY) (09/21/90)

Index Number: 10571

>From: Norman Coombs
>Subj: reading thermometer via a computer
 
>     I am looking for some way or some equipment which would allow
>me to connect a personal thermometer or  barometer  or  some  such
>simple  measuring  device  to my personal computer.  I want to get
>the data from the thermometer or such into the computer.   Then  I
>can store or read it from my pc.  Surely, scientists do this daily
>with expensive equipment.  Is there an inexpensive way to do  this
>at  home  using  ordinary personal equipment at a moderate price??
>Anybody doing this or know  how  or  know  where  I  can  buy  the
>appropriate equipment and/or software?
 
 
Hi Norman,
 
     I hope you've gotten some response to your request.  I'm about
3 weeks or more behind in reading my buffer so I'm  really  out  of
touch.  I  have time to run a program that auto logson to the local
BBS  and  downloads  various echos, but haven't hardly had the time
this last month to sit down and read the messages at all.  But I am
getting  caught  up  slowly  now that things have slowed (?!!) down
some.
 
     One or two years ago a buddy of mine and I put together a very
simple circuit that used  a  thermister,  (a  device  that  changes
resistance  as the temp. changed), and a A to D converter (a device
that would allow a linear signal like a varying voltage say, from 1
volt   to   10  volts  like  from  the  thermister,  and  output  a
corresponding digital signal), and hooked it all  up  to  the  user
port on an old Commodore C-64.  We wrote a ten line program to read
the digital info from the user port and convert  it  to  Fahrenheit
display  on  the  CRT.   Took  about one hour to get it running. It
wasn't super accurate, (+/- 1 degree) but then again the parts cost
only 75 cents for the thermister and about 4 dollars for the A to D
converter.  Interesting evening project for anyone who can  read  a
schematic and understands how BCD (Binary coded decimal) works.
 
     Neither  my friend nor I have the schematic anymore as we both
quit hardware hacking the C-64 products a  long  time  ago.   Never
have  tried  hardware  hacking  on the MS-DOS products, but I would
think it could be done (But not on my  machines!  The  C-64's  were
real easy and inexpensive to repair if we blew one up.  I'd shudder
to  think of what I would do if I blew up my DOS machine.  Watching
someone go through withdrawls from not getting his daily "fix" from
FIDO isn't a pretty sight......GRIN)
 
     I'd try a local PC user group (If any) in your area and see if
you can scrounge up another hardware hacker to help you  with  your
type of PC.
 
     Holler at me here if I can help you with more information.
 
 
                          See you later,
                       Dave Willey aka Duffy
 
Duffy's grin for the day.....
 
Hey Pres. Bush-
 
     Let's play COWBOYS and IRAQIS........
 

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