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Cyhist Feb 13 1997 A
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Date: Thu, 13 Feb 1997 12:44:31 -0500
Reply-To: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@SJUVM.STJOHNS.EDU>
Sender: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@SJUVM.STJOHNS.EDU>
From: "christopher f. chiesa" <lvt-cfc@servtech.com>
Subject: Re: CYHIST Digest - 10 Feb 1997 to 11 Feb 1997
In-Reply-To: <199702120537.AAA23547@servtech.com> from "Automatic digest
processor" at Feb 12, 97 00:35:07 am
______________________________________________________________________
Community Memory: Discussion List on the History of Cyberspace ______________________________________________________________________
Ah... the thread about early digital watches and electronic calculators has stirred up some fond memories. I have a "boilerplate" textfile about this, somewhere, but of course can't find it now that I have a use for it... ;-) I'll just have to reconstruct it.
I got my first digital watch at the age of about 12 :-), as a reward from my Dad for winning first place in the school-district-wide 7th-grade math contest. It was as someone here has described: possessed of a red-LED display that only came on when I pressed a button. One press brought up the time (HH:MM), and a second press brought up the date (MM DD). I *think* there *might* have been a running "seconds" (:SS) display that appeared on the THIRD press, but I may be thinking of my SECOND digital watch.
With this first watch, I explored the fringes of weirdness space. We got a new living-room carpet while I had this watch, and as kids are wont to do, my sister and I spent a lot of time scuffing across the rug in shiny shoes and zapping people and objects with static electricity. I discovered that if I set my watch on the mantelpiece above the fireplace, and "zapped" it with my scuff-static, the display would come on, just as if I had pressed the button -- only, of course, without my ever having even TOUCHED it.
I observed that under just the right "twilight" lighting conditions, when I could just make out my arm and the watch face, if I moved my arm slightly while the display was illuminated, the motion of the glowing red digits across my visual field would "lag" the motion of the just-visible silvery case that framed it. The result was that the display digits seemed to "float," "detached" from the watch proper. I presume this to be an artifact of the human visual apparatus, but I would probably never have discovered it if I hadn't had that (type of) watch. (I have since observed the same phenomena with red-LED-display CALCULATORS as well.)
Likewise, if I moved my arm RAPIDLY across my field of vision while staring at a fixed point beyond the watch, I could see "multiple copies" of the time display, with gaps in between. I deduced from this that the display was not constantly-illuminated but rather went on and off at a high frequency. Also, if I moved my arm REALLY fast, some of the individual iterations of the multiple-display would appear to "come apart" -- the segments making up a digit such as "2," would not appear as a complete "2," but as a series of PARTS of a "2" separated by a little bit. I deduced that not only was the display AS A WHOLE going on and off, but also that the very SEGMENTS making up the DIGITS were not all lit up at the same time but went on and off even MORE rapidly than the display-as-a-whole.
Finally this watch died -- or, I should say, "got killed." To wit, I accidentally dropped it from chest height onto the tile floor of our bathroom. When I picked it up and pressed the button to see if it still worked, the display would still illuminate, but in a most strange manner: one SEGMENT -- that is, one single component of one of the "seven-segment" digit-displays -- at a time. If it were 12:34, I might see the top half of the 1 for a half-second or so, then that would disappear and I'd see maybe the lower-left vertical of the 2, again for a half-second, then that would disappear and the uppermost horizontal of the 0 would come on, and so on and so on. I deduced that hitting the floor had made the former too-fast-too-see display duty-cycle MUCH SLOWER. I wish I had thought to take a time-lapse photograph of this business to see whether the display REALLY DID work out to a realistic "time" reading.
My calculator stories start with my Dad's first calculator, around 1973 when I would have been 10. It was a Texas Instruments unit -- I forget the model number, cost $50, and required Dad to get departmental approval to buy it for his work. For the $50 you got addition, subtraction, multiplication, and division, and you could flip a switch and make multiplication and division (but NOT addition or subtraction) operate "repeatedly" with successive presses of the "=" key. I borrowed this calculator frequently and developed a fascination with it, working out such things as a table of the reciprocals of the first 100 integers.
Eventually, and probably to recover access to his OWN calculator, Dad bought me one of my own: a Novus 850 or 860, I forget which. I eventually discovered that THIS calculator emitted an audio-frequency EMF oscillation that I could detect with an old, suction-cup-to-the-side-of-the-phone "telephone tap" coil, and amplify through a hi-fi system. I have tapes, somewhere, of the weird sounds I could get by generating different sequences of digits to the display. Obviously (in retrospect) I was hearing the display driver circuits go through that "too fast to see" on-off sequence I'd first noticed in my digital watch.
My next calculator was a TI 1250, which was the first calculator I owned that had a memory register; this became useful to me when I discovered the iterative method for extracting square, cube, and higher roots by iteration, which technique I had been searching for for several years at that point (I was about 13). I can remember being reluctant to leave home for two weeks of Boy Scout camp that year, because the departure date fell the very DAY AFTER I learned how to extract roots, and my Dad wouldn't let me take my calculator WITH me to camp...
Eventually I got interested in how the calculator actually WORKED, and sussed out the row/column-intersection keyboard-reading scheme. I then built a 2x3-foot panel containing every electrical switch of any description that I could dig out of my Dad's workshop parts pile, wired this up in a matrix duplicating the calculator keyboard, and alligator-clipped it to the calculator's keyboard leads. I could then push, turn, flip, slide, and otherwise manipulate this huge panel of multifarious switches to operate the palm-sized calculator! My Dad was highly amused and brought home one of his electrical-engineering colleagues to see this gizmo. The guy took one look, slapped his forehead, and moaned, "...after all the time it took them to MINIATURIZE this stuff!" :-) Later I scavenged the keyboard from a large desktop calculator and hooked THAT up to the small one. (A friend of mine took this idea so far, with HIS nearly-identical calculator, that he completely REMOVED the "real" keyboard and operated it SOLELY with a desktop-sized replacement. He used to bring this rig in to freshman-year high school science classes when calculators were needed, and it was the talk of the school. I don't recall that I ever got credit for it, though.)
It may have been the same friend whose TI calculator was identical to mine EXCEPT for ONE KEY in one row of the keyboard; we hooked up my original 2-by-3-foot matrix to his keyboard wiring, though, and discovered that he DID have that particular FUNCTION -- TI had simply omitted to WIRE IT UP, presumably in order to offer a less-expensive model off the same assembly line! Just hook up a slightly different keyboard and apply a slightly different keyboard-label overlay plate... We were amazed. This addition- of-the-missing-function MAY have been the reason my friend went TOTALLY over to the external keyboard...
I also discovered that you could SIMULATE the press of a key at "ROW X, COLUMN Y" on the TI-1250 keyboard, by simultaneously pressing three OTHER keys which, with the desired "target" key, formed a rectangle on the keypad. The same thing could be done on my Dad's TI-30 (the first scientific calculator to enter our home and, as far as I could tell, absolutely identical to another, differently-identified model: SR-something; SR-55?), with the added fillip that the TI-30 had "ON" and "OFF" _keys_ instead of a separate "power switch" as on most other calculators -- which meant that you could "turn the calculator ON (or OFF) without ever pressing the ON (or OFF) key(s)," by the "complete- the-rectangle" technique...
Thanks for letting me "press the [MR]* key" on this stuff...
(* MR = Memory Recall)
Chris Chiesa
lvt-cfc@servtech.com
______________________________________________________________________
Reply-To: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@SJUVM.STJOHNS.EDU>
Sender: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@SJUVM.STJOHNS.EDU>
From: "christopher f. chiesa" <lvt-cfc@servtech.com>
Subject: Re: CYHIST Digest - 10 Feb 1997 to 11 Feb 1997
In-Reply-To: <199702120537.AAA23547@servtech.com> from "Automatic digest
processor" at Feb 12, 97 00:35:07 am
______________________________________________________________________
Community Memory: Discussion List on the History of Cyberspace ______________________________________________________________________
Ah... the thread about early digital watches and electronic calculators has stirred up some fond memories. I have a "boilerplate" textfile about this, somewhere, but of course can't find it now that I have a use for it... ;-) I'll just have to reconstruct it.
I got my first digital watch at the age of about 12 :-), as a reward from my Dad for winning first place in the school-district-wide 7th-grade math contest. It was as someone here has described: possessed of a red-LED display that only came on when I pressed a button. One press brought up the time (HH:MM), and a second press brought up the date (MM DD). I *think* there *might* have been a running "seconds" (:SS) display that appeared on the THIRD press, but I may be thinking of my SECOND digital watch.
With this first watch, I explored the fringes of weirdness space. We got a new living-room carpet while I had this watch, and as kids are wont to do, my sister and I spent a lot of time scuffing across the rug in shiny shoes and zapping people and objects with static electricity. I discovered that if I set my watch on the mantelpiece above the fireplace, and "zapped" it with my scuff-static, the display would come on, just as if I had pressed the button -- only, of course, without my ever having even TOUCHED it.
I observed that under just the right "twilight" lighting conditions, when I could just make out my arm and the watch face, if I moved my arm slightly while the display was illuminated, the motion of the glowing red digits across my visual field would "lag" the motion of the just-visible silvery case that framed it. The result was that the display digits seemed to "float," "detached" from the watch proper. I presume this to be an artifact of the human visual apparatus, but I would probably never have discovered it if I hadn't had that (type of) watch. (I have since observed the same phenomena with red-LED-display CALCULATORS as well.)
Likewise, if I moved my arm RAPIDLY across my field of vision while staring at a fixed point beyond the watch, I could see "multiple copies" of the time display, with gaps in between. I deduced from this that the display was not constantly-illuminated but rather went on and off at a high frequency. Also, if I moved my arm REALLY fast, some of the individual iterations of the multiple-display would appear to "come apart" -- the segments making up a digit such as "2," would not appear as a complete "2," but as a series of PARTS of a "2" separated by a little bit. I deduced that not only was the display AS A WHOLE going on and off, but also that the very SEGMENTS making up the DIGITS were not all lit up at the same time but went on and off even MORE rapidly than the display-as-a-whole.
Finally this watch died -- or, I should say, "got killed." To wit, I accidentally dropped it from chest height onto the tile floor of our bathroom. When I picked it up and pressed the button to see if it still worked, the display would still illuminate, but in a most strange manner: one SEGMENT -- that is, one single component of one of the "seven-segment" digit-displays -- at a time. If it were 12:34, I might see the top half of the 1 for a half-second or so, then that would disappear and I'd see maybe the lower-left vertical of the 2, again for a half-second, then that would disappear and the uppermost horizontal of the 0 would come on, and so on and so on. I deduced that hitting the floor had made the former too-fast-too-see display duty-cycle MUCH SLOWER. I wish I had thought to take a time-lapse photograph of this business to see whether the display REALLY DID work out to a realistic "time" reading.
My calculator stories start with my Dad's first calculator, around 1973 when I would have been 10. It was a Texas Instruments unit -- I forget the model number, cost $50, and required Dad to get departmental approval to buy it for his work. For the $50 you got addition, subtraction, multiplication, and division, and you could flip a switch and make multiplication and division (but NOT addition or subtraction) operate "repeatedly" with successive presses of the "=" key. I borrowed this calculator frequently and developed a fascination with it, working out such things as a table of the reciprocals of the first 100 integers.
Eventually, and probably to recover access to his OWN calculator, Dad bought me one of my own: a Novus 850 or 860, I forget which. I eventually discovered that THIS calculator emitted an audio-frequency EMF oscillation that I could detect with an old, suction-cup-to-the-side-of-the-phone "telephone tap" coil, and amplify through a hi-fi system. I have tapes, somewhere, of the weird sounds I could get by generating different sequences of digits to the display. Obviously (in retrospect) I was hearing the display driver circuits go through that "too fast to see" on-off sequence I'd first noticed in my digital watch.
My next calculator was a TI 1250, which was the first calculator I owned that had a memory register; this became useful to me when I discovered the iterative method for extracting square, cube, and higher roots by iteration, which technique I had been searching for for several years at that point (I was about 13). I can remember being reluctant to leave home for two weeks of Boy Scout camp that year, because the departure date fell the very DAY AFTER I learned how to extract roots, and my Dad wouldn't let me take my calculator WITH me to camp...
Eventually I got interested in how the calculator actually WORKED, and sussed out the row/column-intersection keyboard-reading scheme. I then built a 2x3-foot panel containing every electrical switch of any description that I could dig out of my Dad's workshop parts pile, wired this up in a matrix duplicating the calculator keyboard, and alligator-clipped it to the calculator's keyboard leads. I could then push, turn, flip, slide, and otherwise manipulate this huge panel of multifarious switches to operate the palm-sized calculator! My Dad was highly amused and brought home one of his electrical-engineering colleagues to see this gizmo. The guy took one look, slapped his forehead, and moaned, "...after all the time it took them to MINIATURIZE this stuff!" :-) Later I scavenged the keyboard from a large desktop calculator and hooked THAT up to the small one. (A friend of mine took this idea so far, with HIS nearly-identical calculator, that he completely REMOVED the "real" keyboard and operated it SOLELY with a desktop-sized replacement. He used to bring this rig in to freshman-year high school science classes when calculators were needed, and it was the talk of the school. I don't recall that I ever got credit for it, though.)
It may have been the same friend whose TI calculator was identical to mine EXCEPT for ONE KEY in one row of the keyboard; we hooked up my original 2-by-3-foot matrix to his keyboard wiring, though, and discovered that he DID have that particular FUNCTION -- TI had simply omitted to WIRE IT UP, presumably in order to offer a less-expensive model off the same assembly line! Just hook up a slightly different keyboard and apply a slightly different keyboard-label overlay plate... We were amazed. This addition- of-the-missing-function MAY have been the reason my friend went TOTALLY over to the external keyboard...
I also discovered that you could SIMULATE the press of a key at "ROW X, COLUMN Y" on the TI-1250 keyboard, by simultaneously pressing three OTHER keys which, with the desired "target" key, formed a rectangle on the keypad. The same thing could be done on my Dad's TI-30 (the first scientific calculator to enter our home and, as far as I could tell, absolutely identical to another, differently-identified model: SR-something; SR-55?), with the added fillip that the TI-30 had "ON" and "OFF" _keys_ instead of a separate "power switch" as on most other calculators -- which meant that you could "turn the calculator ON (or OFF) without ever pressing the ON (or OFF) key(s)," by the "complete- the-rectangle" technique...
Thanks for letting me "press the [MR]* key" on this stuff...
(* MR = Memory Recall)
Chris Chiesa
lvt-cfc@servtech.com
______________________________________________________________________
