Delay lines

From: Joe <rigdonj_at_intellistar.net>
Date: Sat Mar 21 23:39:24 1998

At 04:35 PM 3/21/98 +0000, you wrote:
>> I know people collect calculators, but I just can't imagine how it can
>> bring the same kind of satisfaction as computer collecting. You can't
>> really hack a calculator. They don't lend themselves very well to
>
>If you'd been at last year's HPCC conference you'd not say that (or that
>they can't do many tricks). We had an improved symbolic algebra library
>written by hackers (not by HP), a calculator monitoring and controlling
>the real world, people programming calculators in machine code, etc.

  Tony is being modest! He brought and demo'd an interface of his own
design that connected to an HP-48 and controlled a robot arm using an I2C
serial interface. He had it moving disks from one peg to another two in
the classic Towers of Hanoi problem.

>
>There were more hacks there than at the average PC user group IMHO
>(although that says more for the average PC user :-().

  A LOT more than in the present WinDoze PC users!

>
>Other hacks have included the HP42SV (an HP42S with 32K RAM, rather than
>the standard 8K), etc.
>
>> restoration efforts. They can't do many tricks. And few of them have any
>
>I'll agree that restoring them is often hard (since they use 100% custom

   I wouldn't say that. I've reverse engineered many of the HP calcs and
can/have successfully repaired 90+ % of them. And not just a few times,
I've repaired hundreds of them. Fortunately the custom parts are usually
the most reliable.


>chips, and spares are not available). On the other hand, there were
>desktop machines using mostly standard components...
>
>> Has anybody ventured a definition of computer that allows us to weed out
>> mere calculators? How about:
>>
>> * must be programmable
>> * must be general purpose
>> * must have alphanumeric input capabilites
>> * must have alphanumeric display capabilites
>>
>> Unfortunately, this would mean that an Altair isn't a computer until you
>> add a terminal, but it keeps those pesky HP-65's out of the group.
>
>It would allow in many of the HP models including (I think) the HP9100,
>since you could link up standard alphanumeric printers and card readers
>
>And what's wrong with the HP65? It was the first handheld programmable,
>after all.
>
>A possible calculator hack. HP sold a version of the HP97 printing
>calculator called the HP97S. It had an external interface box which
>allowed it to read a BCD number from an external device, and also brought
>out the 4 user flags as TTL outputs. Now, the HP67 has a very similar
>internal design, and the interface box is all 4000-CMOS and a couple of
>tiny ROMs as state machines. How about making an HP67S...

   Good idea Tony! The 67 and 97 are almost identical designs. In the
97S, they intercept some of the bus signals and send them to the external
interface as outputs and route input signals from the interface back to the
processor in place of the keyboard inputs. Building a 67S would be very
easy to do. I may try it if I ever get time.

   Joe
>
>>
>> -- Doug
>>
>>
>
>-tony
>
>
Received on Sat Mar 21 1998 - 23:39:24 GMT