28 Feb
2008
28 Feb
'08
1:26 p.m.
Does anyone know when seven segment displays first appeared on the scene?
Presumably the first ones were VF, and LED came later?
(I was just looking at a museum's mock-up of the Apollo mission control
console, and the fake readout is made to look like a 7-seg display; I'm just
surprised that the digital readouts weren't all Nixie-based back then)
cheers
Jules
28 Feb
28 Feb
1:38 p.m.
Jules Richardson wrote:
Does anyone know when seven segment displays first appeared on the
scene? Presumably the first ones were VF, and LED came later?
(I was just looking at a museum's mock-up of the Apollo mission control
console, and the fake readout is made to look like a 7-seg display; I'm
just surprised that the digital readouts weren't all Nixie-based back then)
What about Nixies?
Peace... Sridhar
2:25 p.m.
On Thu, 28 Feb 2008, Jules Richardson wrote:
Date: Thu, 28 Feb 2008 15:26:14 -0600
From: Jules Richardson <jules.richardson99 at gmail.com>
Reply-To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
;
Subject: seven segment display history
Does anyone know when seven segment displays first appeared on the scene?
Presumably the first ones were VF, and LED came later?
Probably incandescent side lite first, maybe electroluminescent,
incandescent Numitron?
(I was just looking at a museum's mock-up of the Apollo mission control
console, and the fake readout is made to look like a 7-seg display; I'm just
surprised that the digital readouts weren't all Nixie-based back then)
cheers
Jules
Peter Wallace
Mesa Electronics
(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.
3:57 p.m.
On 28 Feb 2008 at 15:26, Jules Richardson wrote:
(I was just looking at a museum's mock-up of the
Apollo mission control
console, and the fake readout is made to look like a 7-seg display; I'm just
surprised that the digital readouts weren't all Nixie-based back then)
7-segment displays go back to the 60's at least--I seem to recall
seeing a prototype 60's EL display using the technique. The RCA
Numitron was about 1970, but it was by no means the first.
I strongly doubt that 7 segment displays were used anywhere in the
Apollo program for a very good reason--their failure mode. If a
Nixie is bad, it doesn't light at all. If a single segment fails on
a 7-segment display, the result can be an ambiguous reading with no
indication of failure. For example, if the top segment fails,
there's no way to distinguish between a 4 and a 9 in most displays.
I think that the Apollo technology was neither incandescent 7-segment
nor Nixie gas tube. I suspect, rather, standard projection displays,
where a strip of film in the form of a loop is placed in front of a
light source. They were modular and very easy to replace from the
front of a panel.
See, for example, the following photo from the Apollo 11 mission:
http://www.hq.nasa.gov/office/pao/History/alsj/a11/ap11-S69-
39815HR.jpg
(warning: it's big (558K). You can clearly make out the numeric
displays (and the half-filled ashtrays) on the ops consoles.
BTW, there are many very good photos at
http://www.apolloarchive.com/apollo_gallery.html
Cheers,
Chuck
4:55 p.m.
It was electroluminecent displays:
http://en.wikipedia.org/wiki/Apollo_Guidance_Computer#DSKY_User_interface
Randy
From: cclist at sydex.com
To: cctalk at classiccmp.org
Date: Thu, 28 Feb 2008 15:57:23 -0800
Subject: Re: seven segment display history
On 28 Feb 2008 at 15:26, Jules Richardson wrote:
_________________________________________________________________
Need to know the score, the latest news, or you need your Hotmail?-get your
"fix".
http://www.msnmobilefix.com/Default.aspx
(I was just looking at a museum's mock-up of
the Apollo mission control
console, and the fake readout is made to look like a 7-seg display; I'm just
surprised that the digital readouts weren't all Nixie-based back then)
7-segment displays go back to the 60's at least--I seem to recall
seeing a prototype 60's EL display using the technique. The RCA
Numitron was about 1970, but it was by no means the first.
I strongly doubt that 7 segment displays were used anywhere in the
Apollo program for a very good reason--their failure mode. If a
Nixie is bad, it doesn't light at all. If a single segment fails on
a 7-segment display, the result can be an ambiguous reading with no
indication of failure. For example, if the top segment fails,
there's no way to distinguish between a 4 and a 9 in most displays.
I think that the Apollo technology was neither incandescent 7-segment
nor Nixie gas tube. I suspect, rather, standard projection displays,
where a strip of film in the form of a loop is placed in front of a
light source. They were modular and very easy to replace from the
front of a panel.
See, for example, the following photo from the Apollo 11 mission:
http://www.hq.nasa.gov/office/pao/History/alsj/a11/ap11-S69-
39815HR.jpg
(warning: it's big (558K). You can clearly make out the numeric
displays (and the half-filled ashtrays) on the ops consoles.
BTW, there are many very good photos at
http://www.apolloarchive.com/apollo_gallery.html
Cheers,
Chuck
5:12 p.m.
On 28 Feb 2008 at 18:55, Randy Dawson wrote:
It was electroluminecent displays:
http://en.wikipedia.org/wiki/Apollo_Guidance_Computer#DSKY_User_interface
That was on the onboard guidance computer, not Mission Control. Very
different animals.
On 28 Feb 2008 at 15:26, Jules Richardson wrote:
(I was just looking at a museum's mock-up of the
Apollo mission
control console, and the fake readout is made to look like a 7-seg
display; I'm just surprised that the digital readouts weren't all
Nixie-based back then)
Cheers,
Chuck
8:29 p.m.
On 28 Feb 2008 at 15:26, Jules Richardson wrote:
Does anyone know when seven segment displays first
appeared on the scene?
Presumably the first ones were VF, and LED came later?
(I was just looking at a museum's mock-up of the Apollo mission control
console, and the fake readout is made to look like a 7-seg display; I'm just
surprised that the digital readouts weren't all Nixie-based back then)
Some datapoints:
- early 1900's: patents for segmented numeric displays
- 1963: Friden EC-130 calculator uses 7-seg vector-scan CRT display
- mid-1960's: Apollo Guidance Computer electroluminescent 7-seg displays
The earliest *off-the-shelf* 7-segment display modules that I've run across are
from ca. 1967:
http://www3.telus.net/~bhilpert/tmp/dialco7seg/
As can be seen, they use neon bulbs. The displays themselves are not dated but
other component date codes in the instrument they came out of were in the range
66xx-67xx. The large-format 7-seg LED modules that came out 10-15 years later
look pretty much like copies of these.
Earliest I know of for 7-seg VF and single-envelope-incandescent (RCA numitron
and similar) would be very late 60's, for LED's very early 70's.
(NIXIEs were mid- or late- 50's.)
29 Feb
29 Feb
6:21 a.m.
Brent Hilpert wrote:
The earliest *off-the-shelf* 7-segment display modules
that I've run across are
from ca. 1967:
http://www3.telus.net/~bhilpert/tmp/dialco7seg/
As can be seen, they use neon bulbs. The displays themselves are not dated but
other component date codes in the instrument they came out of were in the range
66xx-67xx.
Now that looks like the sort of thing I saw in the mock-up (unfortunately
there's a lot of reflection in the photo that I took from the perspex screen
they'd covered the model with, so it's probably not worth sharing).
It's impossible to tell from the mock-up exactly what type of technology it
was though; it was just the seven-segment nature that surprised me, as I don't
think I've seen it that early elsewhere (everything was either Nixie or stacks
of side-lit perspex plates with proper formed numerals on them).
Interesting point from Chuck about the possible failure mode of 7-seg's
though. Perhaps they never thought of that!
cheers
Jules
10:46 p.m.
Jules Richardson wrote:
Brent Hilpert wrote:
(.. just reminds me the 'LAMP TEST' button used to be a standard feature on
control consoles, in general; and the 7447 7-seg decoder has a lamp-test input.)
Don't know if it correlates with the sort of equipment you saw, but I agree
with Chuck the mission control consoles in the pic he provided look like
film-projection displays, the numerals are too well-formed. I have one
frequency counter using that type of display.
The earliest *off-the-shelf* 7-segment display
modules that I've run across are
from ca. 1967:
http://www3.telus.net/~bhilpert/tmp/dialco7seg/
As can be seen, they use neon bulbs. The displays themselves are not dated but
other component date codes in the instrument they came out of were in the range
66xx-67xx.
Now that looks like the sort of thing I saw in the mock-up (unfortunately
there's a lot of reflection in the photo that I took from the perspex screen
they'd covered the model with, so it's probably not worth sharing).
It's impossible to tell from the mock-up exactly what type of technology it
was though; it was just the seven-segment nature that surprised me, as I don't
think I've seen it that early elsewhere (everything was either Nixie or stacks
of side-lit perspex plates with proper formed numerals on them).
Interesting point from Chuck about the possible failure mode of 7-seg's
though. Perhaps they never thought of that! 
28 Feb
28 Feb
7:03 p.m.
On Thursday 28 February 2008 16:26, Jules Richardson wrote:
Does anyone know when seven segment displays first
appeared on the scene?
Presumably the first ones were VF, and LED came later?
(I was just looking at a museum's mock-up of the Apollo mission control
console, and the fake readout is made to look like a 7-seg display; I'm
just surprised that the digital readouts weren't all Nixie-based back then)
I'm not sure what appeared when, but I first started messing around with them
back in 1975 or so...
Across the street from the store on Canal St. in NYC where I bought 'em was a
place that sold Nixies, including some of the more oddball ones, but I
don't recall when I first bumped into VF displays. I do have a calculator
from back then that uses them, but can't recall
exactly when it was that I
got it, though.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
29 Feb
29 Feb
3:45 p.m.
Does anyone know when seven segment displays first appeared on the scene?
Presumably the first ones were VF, and LED came later?
There were some filament ones -- 7 long filaments in the obviosu pattern,
in an evacuated envelope. Some looked like vavles (but were generally
wire-ended), others were ina flatter package, looking a bit like an IC.
And of course there were gass discharge 7-segment displays. The obvious
one is the Panaplex, but I think ones in valve-shaped envelops also existed
And don't forget that the HP9100 calculator (1967-ish) drew the vectors
for 7 segment digits on a CRT screen.
-tony
6:35 p.m.
On Feb 29, 2008, at 6:45 PM, Tony Duell wrote:
Some of these were sold under the name "numitron". I have a few
here; I like them, they've got personality. Here are some pics of one
in operation:
http://www.neurotica.com/misc/numitron-powered.jpg
http://www.neurotica.com/misc/numitron-incrementing.mov
-Dave
--
Dave McGuire
Port Charlotte, FL
Does anyone
know when seven segment displays first appeared on the
scene?
Presumably the first ones were VF, and LED came later?
There were some filament ones -- 7 long filaments in the obviosu
pattern,
in an evacuated envelope. Some looked like vavles (but were generally
wire-ended), others were ina flatter package, looking a bit like an IC. 
9:33 p.m.
On Fri, Feb 29, 2008 at 11:45:55PM +0000, Tony Duell wrote:
I have something like that with me here in my bag-o-parts... approx 20mm
by 30mm, with a 2mm-thick body made of a rough, dark ceramic, with a 1mm
thick glass top. It's a 2.5 digit display with + and -. All the leads
come through the back of the package in what appears to be a straight-
through fashion (making it easy to figure out how to hook it up).
There is a vendor and part number etched on the face: Sperry SP-738.
I've never tried to hook it up to anything, and have no idea what
voltages it might want. It's a shame it's only 2.5 digits; if it
were 3.5 digits, it might make an interesting 12-hour clock face.
Not sure what I'd need to do that swings from -199 to +199 off the
top of my head.
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 1-Mar-2008 at 05:20 Z
South Pole Station
PSC 468 Box 400 Temp -59.6 F (-50.9 C) Windchill -94.4 F (-70.2 C)
APO AP 96598 Wind 11.9 kts Grid 11 Barometer 687.4 mb (10350 ft)
Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html
Does anyone know when seven segment displays first appeared on the scene?
Presumably the first ones were VF, and LED came later?
There were some filament ones -- 7 long filaments in the obviosu pattern,
in an evacuated envelope. Some looked like vavles (but were generally
wire-ended), others were ina flatter package, looking a bit like an IC.
11:22 p.m.
Ethan Dicks wrote:
I have something like that with me here in my bag-o-parts... approx 20mm
by 30mm, with a 2mm-thick body made of a rough, dark ceramic, with a 1mm
thick glass top. It's a 2.5 digit display with + and -. All the leads
come through the back of the package in what appears to be a straight-
through fashion (making it easy to figure out how to hook it up).
There is a vendor and part number etched on the face: Sperry SP-738.
I've never tried to hook it up to anything, and have no idea what
voltages it might want. It's a shame it's only 2.5 digits; if it
were 3.5 digits, it might make an interesting 12-hour clock face.
Not sure what I'd need to do that swings from -199 to +199 off the
top of my head.
Temperature?
Your description sounds like the Sperry/Beckman gas-discharge displays, e.g.:
http://www.tube-tester.com/sites/nixie/trade08-panaplex.htm
I think your part number is in there.
Can be cascaded with more digits, or a lot of early DVMs were only 2.5 digits.
1 Mar
1 Mar
4:16 a.m.
On Fri, Feb 29, 2008 at 11:22:16PM -0800, Brent Hilpert wrote:
Ethan Dicks wrote:
Good idea. Even here, 2.5 digits is enough.
I have something like that with me here in my bag-o-parts...
Sperry SP-738.
It's a shame it's only 2.5 digits...
Not sure what I'd need to do that swings from -199 to +199 off the
top of my head.
Temperature? Your description sounds like the Sperry/Beckman
gas-discharge displays, e.g.:
http://www.tube-tester.com/sites/nixie/trade08-panaplex.htm
Yep. That's it. Thanks for the pointer.
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 1-Mar-2008 at 12:10 Z
South Pole Station
PSC 468 Box 400 Temp -58.7 F (-50.4 C) Windchill -87.0 F (-66.1 C)
APO AP 96598 Wind 7.7 kts Grid 133 Barometer 689.0 mb (10291 ft)
Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html
5:08 p.m.
I remember that seven-segment format being used in TTL(Time To
Launch)/MET (Mission Elapsed Time) on big signs by NASA in the early to
mid-1960's.
These were BIG digits that could be read from long distances. The
segments were formed by putting together incandescent lights in rows and
columns, and a seven-segment rendition made the digits. Also, many
sports scoreboards did (and still today) use a similar seven-segment
rendition using individual incandescent lamps to form segments.
Also, Brent mentioned the HP 9100A using a 7-segment rendition. True,
but the much earlier (1963 versus 1968) Friden 130 used a seven segment
rendition on its CRT display. It was slightly modified so that the "1"
was centered (by slightly shifting the deflection to the left a bit when
a 1 was displayed). Also, a number of calculators introduced prior to
the HP 9100 utilized CRT displays with seven-segment renditions,
including the Victor 3900, and a couple of machines sold under contract
under the Busicom brand name, but designed and manufactured by Wyle
Laboratories (among them the Busicom 202), as well as Wyle Laboratories'
original WS-01 and WS-02 calculators. These machines were all made
between 1965 and 1968.
The mission-control consoles of the 1960's and early '70's (before CRT
displays pretty much displaced discrete displays) typically used
projection-type displays, with small incandescent lights for each digit,
which would shine through a photomask of the shape of the digit, and be
focused on a frosted glass or plastic screen. I had an old digital
clock years ago, using transistorized ring counters that used these type
of displays. They were very readable, and nice, naturally formed
digits, with a nice white digit against at darker background. The clock
was made in 1966 if I remember correctly. Wish I still had that
thing...it ended up getting tossed out by my parents :-(
Rick Bensene
The Old Calculator Museum
http://oldcalculatormuseum.com
8:53 p.m.
Rick Bensene wrote:
I remember that seven-segment format being used in TTL(Time To
Launch)/MET (Mission Elapsed Time) on big signs by NASA in the early to
mid-1960's.
These were BIG digits that could be read from long distances. The
segments were formed by putting together incandescent lights in rows and
columns, and a seven-segment rendition made the digits. Also, many
sports scoreboards did (and still today) use a similar seven-segment
rendition using individual incandescent lamps to form segments.
It's my suspicion that stadium or horsetrack display boards were the
first practical use of 7-seg displays, probably around the 1920s. I've been
intending to go looking for historical photos of large long-established
stadiums such as Yankee or some such, sometime.
Also, Brent mentioned the HP 9100A using a 7-segment
rendition. True,
but the much earlier (1963 versus 1968) Friden 130 used a seven segment
rendition on its CRT display.
Actually, it was Tony who mentioned the HP9100A; I had already mentioned
the Friden 130 earlier in the thread. (And I used Rick's web site to
confirm the year before I stuck my neck out!)
--
(A lot of the points in this thread were mentioned on the list a year or
so ago, in the AGC 7-seg display discussion.)
5921
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16 comments
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participants (11)
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ard＠p850ug1.demon.co.uk -
cclist＠sydex.com -
ethan.dicks＠usap.gov -
hilpert＠cs.ubc.ca -
jules.richardson99＠gmail.com -
mcguire＠neurotica.com -
pcw＠mesanet.com -
ploopster＠gmail.com -
rdawson16＠hotmail.com -
rickb＠bensene.com -
rtellason＠verizon.net