29 Sep
2008
29 Sep
'08
3:44 p.m.
Hi, All,
Since one of the first computers I ever got my hands on as a kid (Quest
Elf) happened to have TIL311 HEX displays, I've long been fascinated with
display technology of that vintage. I was poking around for images of
some of the related displays to the TIL311 and ran across a couple of
links with pictures and some history...
http://www.decodesystems.com/old-displays.html
http://www.decadecounter.com/vta/tubepage.php?item=33
In particular, I notice that one of the displays I have one of is a
TIL305 or MAN2 (no logo on mine). I was also looking at the TIL306
or TIL308, but don't happen to have any of those.
I do have a reasonable quantity of TIL311s for my various Elf and Elf2000
machines and even a set that came with an INS8073 SBC. I would love to
find a couple more TIL305s so I can round out an old project, plus I had
an idea for a project that would be interesting to use TIL306s or TIL308s
(don't care about where the decimal point is, so either is acceptable),
but ISTR some discussion on the list a while back about those in particular,
possibly as replacements to some HP counter, and how difficult and
expensive they are to obtain.
TIL311s are frequently found on eBay for various prices; I've gotten
them myself for as little as $2.50 each in small quantities. I doubt
that TIL306s and TIL308s are anywhere near that inexpensive, no matter
what the quantity, but I thought I'd ask if anyone has recently found
any place selling them. I'm not trying to repair a bit of vintage kit,
so I'm not willing to pay "any" price for them - if they are too expensive
(as I suspect they are), then I will find some other display.
Yes, non-driven LEDs are inexpensive to free and modern microcontrollers
can drive wads of LEDs easily and cheaply, but what I'm going for is a
1970s look with 1970s components (i.e., popcorn-logic driven, not micro-
processor-driven). The advantage of the TIL306s and TIL308s is now what
it was then - a high level of integration reducing the overall wiring
complexity and parts count. The disadvantage now as then is that the
displays are more expensive than the entire rest of the device.
They still look cool, though, and that's the real point.
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 29-Sep-2008 at 22:20 Z
South Pole Station
PSC 468 Box 400 Temp -71.3 F (-57.4 C) Windchill -102.3 F (-74.6 C)
APO AP 96598 Wind 7.6 kts Grid 72 Barometer 683.5 mb (10496 ft)
Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html
29 Sep
29 Sep
5:42 p.m.
On Monday 29 September 2008 18:44, Ethan Dicks wrote:
Hi, All,
Since one of the first computers I ever got my hands on as a kid (Quest
Elf) happened to have TIL311 HEX displays, I've long been fascinated with
display technology of that vintage. I was poking around for images of
some of the related displays to the TIL311 and ran across a couple of
links with pictures and some history...
http://www.decodesystems.com/old-displays.html
http://www.decadecounter.com/vta/tubepage.php?item=33
In particular, I notice that one of the displays I have one of is a
TIL305 or MAN2 (no logo on mine). I was also looking at the TIL306
or TIL308, but don't happen to have any of those.
I do have a reasonable quantity of TIL311s for my various Elf and Elf2000
machines and even a set that came with an INS8073 SBC. I would love to
find a couple more TIL305s so I can round out an old project, plus I had
an idea for a project that would be interesting to use TIL306s or TIL308s
(don't care about where the decimal point is, so either is acceptable),
but ISTR some discussion on the list a while back about those in
particular, possibly as replacements to some HP counter, and how difficult
and expensive they are to obtain.
TIL311s are frequently found on eBay for various prices; I've gotten
them myself for as little as $2.50 each in small quantities. I doubt
that TIL306s and TIL308s are anywhere near that inexpensive, no matter
what the quantity, but I thought I'd ask if anyone has recently found
any place selling them. I'm not trying to repair a bit of vintage kit,
so I'm not willing to pay "any" price for them - if they are too expensive
(as I suspect they are), then I will find some other display.
Yes, non-driven LEDs are inexpensive to free and modern microcontrollers
can drive wads of LEDs easily and cheaply, but what I'm going for is a
1970s look with 1970s components (i.e., popcorn-logic driven, not micro-
processor-driven). The advantage of the TIL306s and TIL308s is now what
it was then - a high level of integration reducing the overall wiring
complexity and parts count. The disadvantage now as then is that the
displays are more expensive than the entire rest of the device.
They still look cool, though, and that's the real point.
Yup!
This is neat stuff...
I built a digital counter for a guy back in 1975, using TTL and displays that
I bought on Canal St. in NYC. I still have some number of that sort of
display around, and haven't figured on any particular use for them yet,
plus some that I've salvaged a bit here and there, some two-digit parts,
etc.
No 7446/7 chips on hand to drive them with, though. Or any of the
4000-series CMOS either. :-(
I was always wanting to get my hands on some of those hex or better yet 5x7
displays back in those days to play with. Oh well.
Definitely nifty stuff, for sure.
--
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
8:48 p.m.
On Mon, Sep 29, 2008 at 08:42:38PM -0400, Roy J. Tellason wrote:
On Monday 29 September 2008 18:44, Ethan Dicks wrote:
Nice. We used to have a short block of surplus stores in Columbus while I
was growing up (I picked up a couple cardcages with "Gorf" arcade game cards
and got them working later), but nothing like Canal St.
Hi, All,
Since one of the first computers I ever got my hands on as a kid (Quest
Elf) happened to have TIL311 HEX displays, I've long been fascinated with
display technology of that vintage...
They still look cool, though, and that's the real point.
Yup!
This is neat stuff...
I built a digital counter for a guy back in 1975, using TTL and displays that
I bought on Canal St. in NYC. I still have some number of that sort of
display around, and haven't figured on any particular use for them yet,
plus some that I've salvaged a bit here and there, some two-digit parts,
etc. No 7446/7 chips on hand to drive them with, though.
Or any of the
4000-series CMOS either. :-(
I have one or two of a few different types, but no loose 9368s (only
installed in boards already).
One thought I had for trying to use a reduced-pin-count MCU-based numeric
display was a 7447-type chip on 4-bits of an I/O port, and a 74145-type
BSD decoder on the other half of the port - up to 10 digits easily, or 9
with simple blanking (write 0 to the '145 and don't hang a digit off of it).
Just checking now, it looks like the CD4511 won't render any digits if you
give it an input over "9" (the 7447 has incomplete decoding internally, so
will light various odd segments if you don't stick to 0-9). With a CD4511,
then (and a 74145 or CMOS equiv), one could hook up to 10 digits and just
write "F"s to any positions you wanted to blank.
There used to be a number of interesting digit and segment driver chips
like the ICM7218D (most famously found in Dragon's Lair and Space Ace
scoreboards), but many of them are difficult to find now, and most of
them cost $8 or more new (and still do when you can find them). They
do make things easy, though, as long as they provide enough digits (the
DL/SA scoreboard has 16 total digits and a pair of ICM7218D to drive them).
They are as easy to talk to as a 6522 or 6821 - R/W, register select and
4-bits input - meant to be memory-mapped, but quite easy to talk to on
the other side of a PC parallel port, for example.
Since I have a couple, my only "problem" is that I haven't found an
integrated multi-digit driver chip that drives more than 8 digits
(and using two of the aforementioned driver chips to drive, say, 6+4
digits substantially increases the project cost).
I was always wanting to get my hands on some of those
hex or better yet 5x7
displays back in those days to play with. Oh well.
Back in the day, I just had two TIL-311s and they were attached to my Quest
Elf. I did take a pair of raised-segment LEDs and hook them up to the
User Port on my PET and wrote a simple interrupt wedge to grab a normally-
unused zero-page byte, and at about 30Hz refresh, blast out a pair of
hex digits. I built it when I was 13-14, but I still have it around
somewhere in the bottom of a drawer.
Definitely nifty stuff, for sure.
Oh, yeah. So are small textual and graphical LCD and VFD displays, but
there's a real appeal, to me at least, of the soft glow of red LEDs. Not
quite as cool as Nixies, but those evoke memories of a different era.
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 30-Sep-2008 at 03:00 Z
South Pole Station
PSC 468 Box 400 Temp -73.7 F (-58.7 C) Windchill -112.1 F (-80.1 C)
APO AP 96598 Wind 11.8 kts Grid 51 Barometer 682.4 mb (10538 ft)
Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html
9:34 p.m.
On Monday 29 September 2008 23:48, Ethan Dicks wrote:
I'm not familiar with that one, offhand (and don't have it in my big generic
numbers chart).
I saw the picture of those but don't recall ever actually seeing those
devices.
Yep. I wouldn't mind getting some nixies to play with too, but those are
getting way too complicated too. And are the driver chips for them available
at all any more? What was it, the 7441?
I have a few LCDs I've been meaning to play with, and some VFDs out of
scrapped VCRs, most of which are too application-specific for me to want to
do anything much with them but one or two of the more recently-acquired ones
might be nice to do something with. Tony mentioned some trick in the past
week or two for a similar type of device, though I think that was only a
single indicator, as far as making it work, and I was wondering how that
might apply to a whole display...
But I'm having to spend too much time weeding things out, arranging stuff,
and trying to get things more organized that I haven't had the time to play
with any of it lately, and it'll be a while yet before I get to that point.
Oh well. :-)
--
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
On Mon, Sep 29, 2008 at 08:42:38PM -0400, Roy J.
Tellason wrote:
I miss those stores. Somebody'd posted in here not too long ago about one
place that was still left there that was supposed to be closing up soon, I
think? I never did find out just when that was gonna happen. We were in NYC
on 9/5 for a wedding, but didn't have time to pursue interests like that as
the next day with that storm coming up the coast I ended up in Cape May
County for a funeral.
Maybe my passion for collecting junk and parts has something to do with having
spent so much time in those stores? Nah, that couldn't be... :-)
BTW, the guy whose name was on the first linked page is who ended up with the
one 1802-based system I had, and also the -8 that I had.
On Monday 29 September 2008 18:44, Ethan Dicks
wrote:
Nice. We used to have a short block of surplus stores in Columbus while I
was growing up (I picked up a couple cardcages with "Gorf" arcade game
cards and got them working later), but nothing like Canal St. Hi, All,
Since one of the first computers I ever got my hands on as a kid (Quest
Elf) happened to have TIL311 HEX displays, I've long been fascinated
with display technology of that vintage...
They still look cool, though, and that's the real point.
Yup!
This is neat stuff...
I built a digital counter for a guy back in 1975, using TTL and displays
that I bought on Canal St. in NYC. I still have some number of that sort
of display around, and haven't figured on any particular use for them
yet, plus some that I've salvaged a bit here and there, some two-digit
parts, etc. No 7446/7
chips on hand to drive them with, though. Or any of the
4000-series CMOS either. :-(
I have one or two of a few different types, but no loose 9368s (only
installed in boards already). One thought I had for trying to use a
reduced-pin-count MCU-based numeric
display was a 7447-type chip on 4-bits of an I/O port, and a 74145-type
BSD decoder on the other half of the port - up to 10 digits easily, or 9
with simple blanking (write 0 to the '145 and don't hang a digit off of
it).
Sounds to me like it oughta work. I have some nontrivial discussion of
driving those devices in the _8085 Cookbook_, but it's been a rather long
time since I read it. I do recall them talking about how important it was to
have some way of not pushing too much current through multiplexed displays
when things weren't running yet, or in case of program bugs, etc.
Just checking now, it looks like the CD4511 won't
render any digits if you
give it an input over "9"
I haven't looked at that aspect of that chip.
(the 7447 has incomplete decoding internally, so will
light various odd
segments if you don't stick to 0-9).
With blank for F IIRC, and I always wondered why they did it that way.
With a CD4511, then (and a 74145 or CMOS equiv), one
could hook up to 10
digits and just write "F"s to any positions you wanted to blank.
I don't know what the heck I'd do with ten digits worth of that stuff
though. :-)
There used to be a number of interesting digit and
segment driver chips
like the ICM7218D (most famously found in Dragon's Lair and Space Ace
scoreboards), but many of them are difficult to find now, and most of
them cost $8 or more new (and still do when you can find them).
I seem to recall Radio Shack selling a couple of chips for that purpose,
75491 and 75492. The former had two sets of outputs but fairly limited drive
capabilities, while the latter was open-collector but could drive a good bit
more if I'm remembering right. They didn't seem to be too friendly to
common-anode displays, which is what I was wanting to use at the time.
They do make things easy, though, as long as they
provide enough digits (the
DL/SA scoreboard has 16 total digits and a pair of ICM7218D to drive them).
I'm going to have to see if I can remember to snag a datasheet on those at
some point.
They are as easy to talk to as a 6522 or 6821 - R/W,
register select and
4-bits input - meant to be memory-mapped, but quite easy to talk to on
the other side of a PC parallel port, for example.
I seem to recall Osborne using one of those, might've been the 6821, and I
don't think it took too much in the way of glue logic to make it work on the
z80 bus.
Since I have a couple, my only "problem" is
that I haven't found an
integrated multi-digit driver chip that drives more than 8 digits
(and using two of the aforementioned driver chips to drive, say, 6+4
digits substantially increases the project cost).
Yeah, there was a time when I immersed myself in those sorts of ideas too,
and the chips never seemed to go quite as far as I wanted 'em to. :-)
I was always
wanting to get my hands on some of those hex or better yet
5x7 displays back in those days to play with. Oh well.
Back in the day, I just had two TIL-311s and they were attached to my Quest
Elf. I did take a pair of raised-segment LEDs and hook them up to the
User Port on my PET and wrote a simple interrupt wedge to grab a normally-
unused zero-page byte, and at about 30Hz refresh, blast out a pair of
hex digits. I built it when I was 13-14, but I still have it around
somewhere in the bottom of a drawer. Definitely
nifty stuff, for sure.
Oh, yeah. So are small textual and graphical LCD and VFD displays, but
there's a real appeal, to me at least, of the soft glow of red LEDs. Not
quite as cool as Nixies, but those evoke memories of a different era. 
30 Sep
30 Sep
3 a.m.
for TIL305 try
http://www.electronicsurplus.com/commerce/catalog/srhkeyword.cz;jsessionid=…
http://www.electronicsurplus.com/commerce/catalog/product.jsp?product_id=78…
http://www.electronicsurplus.com/commerce/catalog/product.jsp?product_id=91…
http://www.electronicsurplus.com/commerce/catalog/product.jsp?product_id=93…
last link is factory new ^
Chris
5:54 a.m.
On Tue, Sep 30, 2008 at 12:34:03AM -0400, Roy J. Tellason wrote:
I'm not familiar with that one, offhand (and don't have it in my big generic
numbers chart).
I can't look it up to verify at the moment (no satellite) in case I have
some digits swapped, but the part I'm thinking of was used in the RCA
MicroTutor II (the later 1802-based one, not the earlier 1801-based one),
a hand-held 1802 device that generates a lot of discussion on the cosmacelf
Yahoo Group, and the Quest SuperElf, among other places. The part is, IIRC,
a Fairchild part that does the same sort of decoding and segment driving
as a 7447. I couldn't describe any differences off the top of my head
though (except a different pinout).
Yes, if you are depending on the multiplexing to limit your current. The
trick there is that a steadily-lit red LED might be able to take up to
20mA with no problems (10mA should light it, ISTR), so in that arrangement,
you select an input voltage, calculate the voltage drop across the LED,
then use Ohm's Law to pick the value for your current limiting resistor
(something like 220 Ohms for driving a bog-standard red LED from +5V).
The trick there is "steadily-lit" - if you are strobing an array of
individual LEDs, you can frequently get away with no current-limiting
resistor as long as you don't stop strobing and accidentially drive an
LED junction on "full". One advantage of this technique is that you can
up the momentary brightness compared with a non-multiplexed bank of LEDs,
helping to make up for the fact that you _aren't_ lighting each lit
junction all the time. This trick is apparently very helpful with IR
LEDs in particular, since a remote control is always sending pulses,
not lighting up and staying lit. You can pump a lot of instantaneous
current through the output LED, as long as you don't leave it on too
long.
Thank you for mentioning this... I just read over an ancient TI datasheet
for the 7446-7449 family of decoder/drivers and there it is. I hadn't
really stared at that end of the decoded pattern to see that "F" renders
as blank. That could end up being quite handy.
I have several ideas, one of which is finishing the revival of a rackmount
GPS frontpanel (a Datum 9390). I was way too late to save the guts of it
when it was scrapped last year, but they let me have the 19" plate with
an 11 button input panel, an Optrex 4x40 LCD, and a 9-digit "clock"
(hours/minutes/seconds + day-of-year). It has some oversized HP 7-segment
LEDs mounted on a small board with a 20-pin DIP socket - I could pull the
digits from the board and wire them up (at the same visual spacing) any
way I like, but _if_ I can come up with a circuit that will drive nine
7-segment displays with the A-G segments in parallel and individual
common lines, I could give this frontpanel the appearance it had when
it was a working GPS. More modern versions have either a backlit LCD
or a VFD - no glowing red digits.
I think I got mine from the Dragon's Lair Project webpage years ago. I
snarfed some code from Daphne (the laserdisc game emulator) and bodged
it up to let me do a variety of things from the command line (set individual
digits, cycle through various patterns, and to even use the two 6-digit
score lines as YYMMDD date and HHMMSS time). The code to set an individual
digit is not particularly complex.
I got mine in the late 1970s in a $2 multi-pack at Radio Shack. I don't
have as many as I used to due to youthful exhuberance and destructive
testing (hint: they can't take a 9V supply without a resistor ;-)
The 7441 sounds right. I think someone rebadged a bunch of 7441s as 74141s
(or something similar), but they aren't particularly cheap. I think I have
one 7441 in a drawer.
No 7446/7 chips on hand to drive them with, though.
Or any of the
4000-series CMOS either. :-(
I have one or two of a few different types, but no loose 9368s (only
installed in boards already). One thought I
had for trying to use a reduced-pin-count MCU-based numeric
display was a 7447-type chip on 4-bits of an I/O port, and a 74145-type
BSD decoder on the other half of the port...
Sounds to me like it oughta work. I have some nontrivial discussion of
driving those devices in the _8085 Cookbook_, but it's been a rather long
time since I read it. I do recall them talking about how important it was to
have some way of not pushing too much current through multiplexed displays
when things weren't running yet, or in case of program bugs, etc. Just checking
now, it looks like the CD4511 won't render any digits if you
give it an input over "9"
I haven't looked at that aspect of that chip.
(the 7447 has incomplete decoding internally, so
will light various odd
segments if you don't stick to 0-9).
With blank for F IIRC, and I always wondered why they did it that way. With a CD4511,
then (and a 74145 or CMOS equiv), one could hook up to 10
digits and just write "F"s to any positions you wanted to blank.
I don't know what the heck I'd do with ten digits worth of that stuff
though. :-) I seem to recall Radio Shack selling a couple of chips
for that purpose,
75491 and 75492.
I'm unfamiliar with those. I should look them up.
The former had two sets of outputs but fairly limited
drive
capabilities, while the latter was open-collector but could drive a good bit
more if I'm remembering right.
The 7446-7449 family has a similar spread of features. The 7448, IIRC,
can only sink 6mA and is designed to be externally buffered.
They didn't seem to be too friendly to
common-anode displays, which is what I was wanting to use at the time.
Ah... that is one of the reasons why TI made a spread of parts with
different drive capacities and other features.
They do make
things easy, though, as long as they provide enough digits (the
DL/SA scoreboard has 16 total digits and a pair of ICM7218D to drive them).
I'm going to have to see if I can remember to snag a datasheet on those at
some point. I seem to recall Osborne using one of those,
might've been the 6821, and I
don't think it took too much in the way of glue logic to make it work on the
z80 bus.
Nor the 6502 or pretty much any 8-bitter. The only thing that gets
sticky is when you have to fiddle between /WR + /RD lines vs a single
/WR-RD line ("motorola" vs "intel" bus standard as frequently
described
in docs on textual LCDs and VFDs).
.... I did
take a pair of raised-segment LEDs...
I saw the picture of those but don't recall ever actually seeing those
devices. Oh, yeah. So
are small textual and graphical LCD and VFD displays, but
there's a real appeal, to me at least, of the soft glow of red LEDs. Not
quite as cool as Nixies, but those evoke memories of a different era.
Yep. I wouldn't mind getting some nixies to play with too, but those are
getting way too complicated too. And are the driver chips for them available
at all any more? What was it, the 7441? I have a few LCDs I've been meaning to play with,
and some VFDs out of
scrapped VCRs, most of which are too application-specific for me to want to
do anything much with them but one or two of the more recently-acquired ones
might be nice to do something with.
Many of those appliance displays are unformatted - the controller/driver
is embedded on the main board of the device. The ones I've played with
have an HD44780 or some graphical controller (depending on the display
type), and that takes care of strobing, driving voltages, fonts, etc.
You just worry about register-level formatting of what you want to put
on the display.
I don't have any experience driving "naked" VFDs, but I have a few
panels and wouldn't mind taking a stab at it someday.
Tony mentioned some trick in the past
week or two for a similar type of device, though I think that was only a
single indicator, as far as making it work, and I was wondering how that
might apply to a whole display...
Much in the same way as things that kicked off this thread to begin
with - you have to have some part (dedicated or a custom-programmed MCU
for example) that strobes through the various display elements (pixels/segments)
and that you can address externally to end up with the desired bits lit and
unlit. I have a few naked LCDs that I'd love to play with, but with
all the formatted LCDs that are out there, I've never gotten into
driver specifics.
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 30-Sep-2008 at 12:20 Z
South Pole Station
PSC 468 Box 400 Temp -74.6 F (-59.2 C) Windchill -113.9 F (-81.1 C)
APO AP 96598 Wind 12.3 kts Grid 50 Barometer 682.2 mb (10545 ft)
Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html
10:02 a.m.
On Tuesday 30 September 2008 08:54, Ethan Dicks wrote:
(Snip)
I can't look it up to verify at the moment (no satellite) in case I have
some digits swapped, but the part I'm thinking of was used in the RCA
MicroTutor II (the later 1802-based one, not the earlier 1801-based one),
a hand-held 1802 device that generates a lot of discussion on the cosmacelf
Yahoo Group, and the Quest SuperElf, among other places. The part is,
IIRC, a Fairchild part that does the same sort of decoding and segment
driving as a 7447. I couldn't describe any differences off the top of my
head though (except a different pinout).
There seems to be a fair amount of 9000-numbered stuff and other early TTL
that I haven't managed to accumulate much data on yet...
(Snip)
Thank you for mentioning this... I just read over an ancient TI datasheet
for the 7446-7449 family of decoder/drivers and there it is. I hadn't
really stared at that end of the decoded pattern to see that "F" renders
as blank. That could end up being quite handy.
The rest of the decoding is still rather weird, though. :-)
(Snip)
They're in my big genereic number chart, the last two entries just before the
z80 stuff:
http://www.classiccmp.org/rtellason/by-generic-number.html
I remember some of that, though it's been a rather long while since I looked
at any of those specs.
Yup.
(Snip)
Sounds a little familiar...
I got mine in the late 1970s in a $2 multi-pack at Radio Shack. I don't
have as many as I used to due to youthful exhuberance and destructive
testing (hint: they can't take a 9V supply without a resistor ;-)
No surprise there. :-)
The 7441 sounds right. I think someone rebadged a bunch of 7441s as 74141s
(or something similar), but they aren't particularly cheap. I think I have
one 7441 in a drawer.
I had one assembly that I'd picked up somewhere, a bunch of tubes in sockets
with a bit of perfboard underneath each having a 7441 on it, and that went
to the same guy that took the 1802-based system and the pdp8, he had a thing
for nixies as I recall.
Or on the board containing the display, often underneath it, at least in the
case of the VFDs. And those are very machine-specific too.
This was a VFD type of device he was talking about, I think. I'll have to
play with one at some point, and see what I can manage to get going with it.
A brief search a while back didn't yield much information, they don't seem
to be generic devices at all but mostly manufactured for the specific
equipment they're going into and sold in large quantities. Perhaps if I can
find the time to dig out some VCR service manuals and peruse that portion of
the circuitry I can get more of a grip on them.
--
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
I have one or two of a few different types, but no
loose 9368s (only
installed in boards already).
I'm not familiar with that one, offhand (and don't have it in my big
generic numbers chart). (the 7447 has incomplete decoding internally, so will
light various odd
segments if you don't stick to 0-9).
With blank for F IIRC, and I always wondered why they did it that way. I seem to
recall Radio Shack selling a couple of chips for that purpose,
75491 and 75492.
I'm unfamiliar with those. I should look them up. The former
had two sets of outputs but fairly limited drive capabilities,
while the latter was open-collector but could drive a good bit more if
I'm remembering right.
The 7446-7449 family has a similar spread of features. The 7448, IIRC,
can only sink 6mA and is designed to be externally buffered. They
didn't seem to be too friendly to common-anode displays, which is
what I was wanting to use at the time.
Ah... that is one of the reasons why TI made a spread of parts with
different drive capacities and other features. I seem to
recall Osborne using one of those, might've been the 6821,
and I don't think it took too much in the way of glue logic to make it
work on the z80 bus.
Nor the 6502 or pretty much any 8-bitter. The only thing that gets
sticky is when you have to fiddle between /WR + /RD lines vs a single
/WR-RD line ("motorola" vs "intel" bus standard as frequently
described
in docs on textual LCDs and VFDs). .... I did take a pair of raised-segment LEDs...
I saw the picture of those but don't recall ever actually seeing those
devices. Oh, yeah. So are small textual and graphical LCD and
VFD displays, but
there's a real appeal, to me at least, of the soft glow of red LEDs.
Not quite as cool as Nixies, but those evoke memories of a different
era.
Yep. I wouldn't mind getting some nixies to play with too, but those
are getting way too complicated too. And are the driver chips for them
available at all any more? What was it, the 7441? I have a few
LCDs I've been meaning to play with, and some VFDs out of
scrapped VCRs, most of which are too application-specific for me to want
to do anything much with them but one or two of the more
recently-acquired ones might be nice to do something with.
Many of those appliance displays are unformatted - the controller/driver
is embedded on the main board of the device. The ones I've played with have an HD44780 or some
graphical controller
(depending on the display type), and that takes care of strobing, driving
voltages, fonts, etc. You just worry about register-level formatting of
what you want to put on the display.
Yep, I need to figure out some uP that I want to play with those with. Or
maybe rig something with a parallel cable...
I don't have any experience driving
"naked" VFDs, but I have a few
panels and wouldn't mind taking a stab at it someday.
Nor do I.
Tony
mentioned some trick in the past week or two for a similar type of
device, though I think that was only a single indicator, as far as
making it work, and I was wondering how that might apply to a whole
display...
Much in the same way as things that kicked off this thread to begin
with - you have to have some part (dedicated or a custom-programmed MCU
for example) that strobes through the various display elements
(pixels/segments) and that you can address externally to end up with the
desired bits lit and unlit. I have a few naked LCDs that I'd love to play
with, but with all the formatted LCDs that are out there, I've never gotten
into driver specifics. 
11:12 a.m.
On Sep 30, 2008, at 12:34 AM, Roy J. Tellason wrote:
Yep. I wouldn't mind getting some nixies to play
with too, but
those are
getting way too complicated too. And are the driver chips for them
available
at all any more? What was it, the 7441?
I do a lot of stuff with Nixie tubes.
7441s are pretty rare, but 74141s are around. The Russian clone
of the 74141, the K155, is readily available on eBay at reasonable
prices. I've used quite a few of them with good results.
Nixie tubes really aren't that difficult to drive. If you decide
to give them a shot, drop me a note and I'll send you some info to
get you started.
-Dave
--
Dave McGuire
Port Charlotte, FL
11:21 a.m.
On Tuesday 30 September 2008 14:12, Dave McGuire wrote:
On Sep 30, 2008, at 12:34 AM, Roy J. Tellason wrote:
That numbering is completely new to me, but then I haven't kept up with a
fair amount of stuff anyhow. Do you know of datasheets for those out there
somewhere?
Yep. I wouldn't mind getting some nixies to
play with too, but
those are
getting way too complicated too. And are the driver chips for them
available
at all any more? What was it, the 7441?
I do a lot of stuff with Nixie tubes.
7441s are pretty rare, but 74141s are around. The Russian clone
of the 74141, the K155, is readily available on eBay at reasonable
prices. I've used quite a few of them with good results. Nixie tubes really aren't that difficult to
drive. If you decide
to give them a shot, drop me a note and I'll send you some info to
get you started.
I wouldn't mind playing with some, if I had the appropriate transformer and
such to drive them with. Used to be that you could get a transformer with a
nominal 125VAC output fairly easily, I haven't looked to see if they're out
there these days.
Somewhere in my box of connectors I have a bag of "nixie sockets" that I was
sent, I'm gonna have to take a pic of those and post it and see if anybody
can use 'em.
--
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
2:03 p.m.
On Sep 30, 2008, at 2:21 PM, Roy J. Tellason wrote:
I've put a copy of the K155 datasheet here:
http://www.neurotica.com/misc/74141-russK155.gif
Ugh, line power. Much safer to power stuff from low-voltage DC.
Try this step-up circuit; it is based on an MC34063 app note design
which I've tuned a bit and adapted for current component availability:
http://www.neurotica.com/misc/step-up-regulator.png
It's cheap, easy to build, and powers Nixies nicely.
-Dave
--
Dave McGuire
Port Charlotte, FL
I do a lot
of stuff with Nixie tubes.
7441s are pretty rare, but 74141s are around. The Russian clone
of the 74141, the K155, is readily available on eBay at reasonable
prices. I've used quite a few of them with good results.
That numbering is completely new to me, but then I haven't kept up
with a
fair amount of stuff anyhow. Do you know of datasheets for those
out there
somewhere? 
Nixie tubes
really aren't that difficult to drive. If you decide
to give them a shot, drop me a note and I'll send you some info to
get you started.
I wouldn't mind playing with some, if I had the appropriate
transformer and
such to drive them with. Used to be that you could get a
transformer with a
nominal 125VAC output fairly easily, I haven't looked to see if
they're out
there these days. 
8:16 p.m.
On Tuesday 30 September 2008 17:03, Dave McGuire wrote:
Ugh, line power. Much safer to power stuff from low-voltage DC.
I've been messing around with line power ever since I was a kid. (And all the
batteries were dead, anyhow. :-) Not that big of a deal, really.
On Sep 30, 2008, at 2:21 PM, Roy J. Tellason wrote:
I've put a copy of the K155 datasheet here:
http://www.neurotica.com/misc/74141-russK155.gif
Ok.
I do a
lot of stuff with Nixie tubes.
7441s are pretty rare, but 74141s are around. The Russian clone
of the 74141, the K155, is readily available on eBay at reasonable
prices. I've used quite a few of them with good results.
That numbering is completely new to me, but then I haven't kept up
with a fair amount of stuff anyhow. Do you know of datasheets for those
out there somewhere? Nixie tubes really aren't that difficult to
drive. If you decide
to give them a shot, drop me a note and I'll send you some info to
get you started.
I wouldn't mind playing with some, if I had the appropriate
transformer and such to drive them with. Used to be that you could get a
transformer with a nominal 125VAC output fairly easily, I haven't looked
to see if they're out there these days. Try this step-up circuit; it is based on an MC34063
app note design
which I've tuned a bit and adapted for current component availability:
http://www.neurotica.com/misc/step-up-regulator.png
It's cheap, easy to build, and powers Nixies nicely.
Yeah, but a transformer, bridge rectifier, and filter cap is *so* much
simpler.
--
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
1 Oct
1 Oct
10:10 a.m.
On Sep 30, 2008, at 11:16 PM, Roy J. Tellason wrote:
I've been messing around with line power ever since I was a kid.
(And all the
batteries were dead, anyhow. :-) Not that big of a deal, really.
I've been messing with it for just as long, but still...ugh. It
is just a pain to deal with, IMO.
Ugh. ;)
-Dave
--
Dave McGuire
Port Charlotte, FL
I wouldn't mind playing with some, if I had the
appropriate
transformer and such to drive them with. Used to be that you
could get a
transformer with a nominal 125VAC output fairly easily, I
haven't looked
to see if they're out there these days.
Ugh, line power. Much safer to power stuff from low-voltage DC. Try this
step-up circuit; it is based on an MC34063 app note design
which I've tuned a bit and adapted for current component
availability:
http://www.neurotica.com/misc/step-up-regulator.png
It's cheap, easy to build, and powers Nixies nicely.
Yeah, but a transformer, bridge rectifier, and filter cap is
*so* much
simpler. 
10:47 a.m.
On 1 Oct 2008 at 13:10, Dave McGuire wrote:
I was under the impression that old "B+ supply" transformers were
getting hard to find. Not so, apparently. I popped open a 1990's
stereo receiver that was about to hit the junkpile to see what might
be salvaged (one of the hybrid output ICs had fizzled and would cost
more to replace than the receiver was worth)--and found a 70-0-70
(140vct) transformer in the power supply. Perfect for a Nixie
application.
Cheers,
Chuck
Yeah, but a
transformer, bridge rectifier, and filter cap is
*so* much
simpler.
Ugh. ;)
5:41 p.m.
On Wednesday 01 October 2008 13:47, Chuck Guzis wrote:
On 1 Oct 2008 at 13:10, Dave McGuire wrote:
I was under the impression that old "B+ supply" transformers were
getting hard to find. Not so, apparently. I popped open a 1990's
stereo receiver that was about to hit the junkpile to see what might
be salvaged (one of the hybrid output ICs had fizzled and would cost
more to replace than the receiver was worth)--and found a 70-0-70
(140vct) transformer in the power supply. Perfect for a Nixie
application.
Sounds good. And that's why I throw almost *nothing* away. :-)
--
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
Yeah,
but a transformer, bridge rectifier, and filter cap is
*so* much
simpler.
Ugh. ;) 
2 Oct
2 Oct
10:29 a.m.
I was under the impression that old "B+
supply" transformers were
getting hard to find. Not so, apparently. I popped open a 1990's
They're not _that_ hard to fimd, and there are plenty od workarounds.
Since nixie tube current is pretty low, and the supply doesn't have to be
that well smoothed, you can use a voltage doubler (or even a larger
diode-capacitor multiplier circuit) to get that voltage from a
lower voltage trasnformer.
Alternatively, consider using a transformer 'back to front'. Start of
taking in mains and stepping it down to, say, 12V AC using a normal
transformer in the conventional way. Yo ucan rectify/smooth/regulate that
for your logic supply. But then take another 220V-12V trasnformer and
connect the 12V winding to the secondary (12V) side of the first
transformer. You'll get around 230V from the other (original primary)
winding of that transformer.
OK, it's inefficient, but it's fine for nixie tubes, 1 and 2 valvle
headphone radios, and the like.
-tony
12:41 p.m.
On 2 Oct 2008 at 18:29, Tony Duell wrote:
Alternatively, consider using a transformer 'back
to front'. Start of
taking in mains and stepping it down to, say, 12V AC using a normal
transformer in the conventional way. Yo ucan rectify/smooth/regulate that
for your logic supply. But then take another 220V-12V trasnformer and
connect the 12V winding to the secondary (12V) side of the first
transformer. You'll get around 230V from the other (original primary)
winding of that transformer.
If you happen to have one handy in the USA, of course. Although
"universal" 95-240v transformers can be found in the US, most of the
small ones (such as are found in wall warts) are 120vac primaries
only.
But if I had a 12vdc supply at sufficient current and needed to power
some nixies, I'd be sore tempted to work up a boost supply using any
of the currently available DC-DC converter ICs. EDN/Electronic
Design is full of such circuits (e.g. using the Maxim MAX1771). Much
more compact and not requiring much in the way of a DC filter
capacitor.
Where I'd draw the line is with any small signal application, such as
a receiver using tubes/valves. Those converter ICs can really
generate a lot of RF noise.
Cheers,
Chuck
11:39 p.m.
If I need a small HV power supply " on-the-cheap " I visit the local photo
shop. The disposable cameras with flash have a nifty little DC-DC converter
built-in and the shops throw them all in the trash after the film has been
recovered. They run off of a single AA ( 1.5 VDC ) battery. The batteries
are usually at about 90% of their life still left. And did I mention " free
" .....
Best regards, Steven
On 2 Oct 2008 at 18:29, Tony Duell wrote:
> Alternatively, consider using a transformer 'back to front'. Start of
> taking in mains and stepping it down to, say, 12V AC using a normal
> transformer in the conventional way. Yo ucan rectify/smooth/regulate
that
for your logic
supply. But then take another 220V-12V trasnformer and
connect the 12V winding to the secondary (12V) side of the first
transformer. You'll get around 230V from the other (original primary)
winding of that transformer.
If you happen to have one handy in the USA, of course. Although
"universal" 95-240v transformers can be found in the US, most of the
small ones (such as are found in wall warts) are 120vac primaries
only.
But if I had a 12vdc supply at sufficient current and needed to power
some nixies, I'd be sore tempted to work up a boost supply using any
of the currently available DC-DC converter ICs. EDN/Electronic
Design is full of such circuits (e.g. using the Maxim MAX1771). Much
more compact and not requiring much in the way of a DC filter
capacitor.
Where I'd draw the line is with any small signal application, such as
a receiver using tubes/valves. Those converter ICs can really
generate a lot of RF noise.
Cheers,
Chuck
3 Oct
3 Oct
11:27 a.m.
Alternatively,
consider using a transformer 'back to front'. Start of
taking in mains and stepping it down to, say, 12V AC using a normal
transformer in the conventional way. Yo ucan rectify/smooth/regulate that
for your logic supply. But then take another 220V-12V trasnformer and
connect the 12V winding to the secondary (12V) side of the first
transformer. You'll get around 230V from the other (original primary)
winding of that transformer.
If you happen to have one handy in the USA, of course. Although
"universal" 95-240v transformers can be found in the US, most of the
small ones (such as are found in wall warts) are 120vac primaries
only. But if I had a 12vdc supply at sufficient current and
needed to power
some nixies, I'd be sore tempted to work up a boost supply using any
of the currently available DC-DC converter ICs. EDN/Electronic
I really do find iron more reliable than silicon :-)
Design is full of such circuits (e.g. using the Maxim
MAX1771). Much
more compact and not requiring much in the way of a DC filter
capacitor.
Where I'd draw the line is with any small signal application, such as
a receiver using tubes/valves. Those converter ICs can really
generate a lot of RF noise.
Totally OT, but if you're trying to run one of those valved portable
radios that used a 90V HT supply, it's worth noting that a 30V
transformer (the ends of a 15-0-15 winding, for example), voltage
doubled, gives about 84V. That's run all the radios I've tried, including
an AM/FM (yes, a valved FM portable radio) Vidor set.
-tony
12:21 p.m.
On 3 Oct 2008 at 19:27, Tony Duell wrote:
I am suprised. Over here, most mains transformers have
2 off 115V
primary windings that you connect in series for 230V mains (Europe) and
parallel for 115V mains (USA). I assumed (given that 115V-input
transformers are not commonly needed over here) that such things were
available worldwide.
Well, if split-primary transformers were common here, the problem
would be solved wouldn't it? Use one of the primaries as a 120v
secondary and the low-voltage secondary as normal. I used to have a
cache of surplus filament transformers that I'd use to power small
tube/valve projects in that manner.
But all wall-wart supplies that I've seen here (which is about the
only easy way to obtain small power transformers) have a single
120vac primary. It might be that the cost of the extra copper
required for 220vac operation justifies a separate product run for
North America and Japan. (Somewhat OT is that Japanese mains power is
spec-ed somewhere around 100vac. Expats who brought their US-rated
appliances (such as a refrigerator) were often disappointed by the
short motor life when run on Japanese power).
Totally OT, but if you're trying to run one of
those valved portable
radios that used a 90V HT supply, it's worth noting that a 30V
transformer (the ends of a 15-0-15 winding, for example), voltage
doubled, gives about 84V. That's run all the radios I've tried, including
an AM/FM (yes, a valved FM portable radio) Vidor set.
Given that many battery-powered sets used a 45vdc "B" battery, I
would agree with you.
Cheers,
Chuck
1:29 p.m.
But all wall-wart supplies that I've seen here
(which is about the
only easy way to obtain small power transformers) have a single
Ah... The wall-warts we have over here generally have a single primary
winding too. But I don;t consider those to be particularly useful
transformers.
I generally buy 'loose' transformers from RS or Farnell. Although at
least one of those companies sells 230V-only transfoemrs in some sizes,
they certainly also sell the dual-primary ones I mentioned.
120vac primary. It might be that the cost of the
extra copper
required for 220vac operation justifies a separate product run for
North America and Japan. (Somewhat OT is that Japanese mains power is
spec-ed somewhere around 100vac. Expats who brought their US-rated
Indeed. I've worked on many devices, particularly HP, which have 4
voltage selector settings -- 110V, 120V, 220 and 240V. There were
typically 2 types of transformer used - -one had 2 primaries tapped
0-100-120V, the other had 1 primarly like that and a second primary of
120V (no tap). The settings worked as follows :
100V --For the first type, the 2 100V sections of the windings in
parallel. For the second type, mains to the 100V sectionm, then this
acted as an autotransformer providing 120V to the other winding which was
connected in parallel with it
120V -- the 2 120V windings in parallel
220V -- A 120V winidng in series with a 100V one
240V -- The 2 120V windings in series.
The HP THinkjet printers used the latter type, with a mains input module
that contained the IEC connector, mains filter, fuse holder and a set of
5 contacts operated by a rotatable drum for the voltage selection. For
some reason the exact operation of this is not in the Thinkjet service
manual (even though all the rest of the schematic, PCB layouts, theory,
etc are).
The 9836 I've been talking about in another thread was the former type.
Why, I don;t know, the votlage regulator PCB in that machine (the only
thing run off the single secondary winding on the transformer) is happy
with inputs from avout 18V up to 32V at least. So a simple 115/230V
selector should have been fine.
appliances (such as a refrigerator) were often
disappointed by the
short motor life when run on Japanese power).
I am suprised that motors objected to too low a voltage. Wasn't there a
frequency difference too -- I thought that some of Japan was 50Hz. That
might have been more of a problem
Totally OT, but if you're trying to run one
of those valved portable
radios that used a 90V HT supply, it's worth noting that a 30V
transformer (the ends of a 15-0-15 winding, for example), voltage
doubled, gives about 84V. That's run all the radios I've tried, including
an AM/FM (yes, a valved FM portable radio) Vidor set.
Given that many battery-powered sets used a 45vdc "B" battery, I
would agree with you.
3:28 p.m.
On 3 Oct 2008 at 21:29, Tony Duell wrote:
I am suprised that motors objected to too low a
voltage. Wasn't there a
frequency difference too -- I thought that some of Japan was 50Hz. That
might have been more of a problem
Induction motors run on too-low voltage tend to draw too much
current, leading to overheating, particularly in those applications
where a more-or-less constant load that runs the motor near its
nameplate rating is encountered. You can sometimes find under-
voltage protection devices on industrial equipment motors. Many
small motors are impedance-protected, so operating, say, an equipment
cooling fan motor on low voltage is probably safe.
On the other hand, I've run 220v 25Hz induction motors on 120v 60Hz
just fine--or at least they didn't burn up.
I'd seen 45V batteries listed, but I assumed
(incorrectly, I guess) that
they were normally used in pairs to give 90V. I've never seen a radio
that used them, I do have one device, totally off-topic, that should use one.
The 45v batteries were widely used in photoflash units, as well as
some early portable radios. 67.5 and 90v batters were also used here-
-and then for photographic strobe applications, 225, 450 and 510v dry
batteries for very fast recovery times. 510v was the highest-voltage
widely-available primary battery that I'm aware of.
Cheers,
Chuck
6:15 p.m.
On Friday 03 October 2008 14:27, Tony Duell wrote:
I am suprised. Over here, most mains transformers have 2 off 115V
primary windings that you connect in series for 230V mains (Europe) and
parallel for 115V mains (USA). I assumed (given that 115V-input
transformers are not commonly needed over here) that such things were
available worldwide.
I've seen those in some equipment, and not in other stuff from the same mfr.,
said mfr. being into distributing products worldwide. In some cases they'd
use a different transformer, rather than the single more "universal" one.
:-)
--
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
Alternatively, consider using a transformer 'back
to front'. Start of
taking in mains and stepping it down to, say, 12V AC using a normal
transformer in the conventional way. Yo ucan rectify/smooth/regulate
that for your logic supply. But then take another 220V-12V trasnformer
and connect the 12V winding to the secondary (12V) side of the first
transformer. You'll get around 230V from the other (original primary)
winding of that transformer.
If you happen to have one handy in the USA, of course. Although
"universal" 95-240v transformers can be found in the US, most of the
small ones (such as are found in wall warts) are 120vac primaries
only. But if I had a
12vdc supply at sufficient current and needed to power
some nixies, I'd be sore tempted to work up a boost supply using any
of the currently available DC-DC converter ICs. EDN/Electronic
I really do find iron more reliable than silicon :-) 
30 Sep
30 Sep
11:32 a.m.
At 10:12 AM 9/30/2008, you wrote:
On Sep 30, 2008, at 12:34 AM, Roy J. Tellason wrote:
http://www.unicornelectronics.com/IC/7400.html
They have both.
Grant
Yep. I wouldn't mind getting some nixies to
play with too, but
those are
getting way too complicated too. And are the driver chips for them
available
at all any more? What was it, the 7441?
I do a lot of stuff with Nixie tubes.
7441s are pretty rare, but 74141s are around. The Russian clone
of the 74141, the K155, is readily available on eBay at reasonable
prices. I've used quite a few of them with good results.
3:31 p.m.
One thought I had for trying to use a
reduced-pin-count MCU-based numeric
display was a 7447-type chip on 4-bits of an I/O port, and a 74145-type
BSD decoder on the other half of the port - up to 10 digits easily, or 9
with simple blanking (write 0 to the '145 and don't hang a digit off of it).
Most BCD-10 line decoders (I forget if the '145 is like this, but I think
it is) assert no outputs for inputs >9. So you could ahng 10 digits off a
'145 and simply write 1111 or whatever to that port for blanking.
Just checking now, it looks like the CD4511 won't render any digits if you
give it an input over "9" (the 7447 has incomplete decoding internally, so
will light various odd segments if you don't stick to 0-9). With a CD4511,
But I think '1111' blanks the digit for a '47
-tony
9:33 a.m.
BTW, where does a guy find the nice RED plastic lens that is usually put
in front of a bank of 7-segment displays to hide the view of the parts
and show only the lighted segments showing through?
Is it just red plexiglass or is there a specific color and transmissive
capability that is typically used?
I like playing with RED LEDs too and have a bunch of clocks and things
to build and want to put such a filter/lens in front of them.
Thanks.
Chris
--
Chris Elmquist
mailto:chrise at pobox.com
9:55 a.m.
Chris Elmquist wrote:
BTW, where does a guy find the nice RED plastic lens
that is usually put
in front of a bank of 7-segment displays to hide the view of the parts
and show only the lighted segments showing through?
Is it just red plexiglass or is there a specific color and transmissive
capability that is typically used?
I bought a piece of this stuff in the 1970s, for a clock project and I
also used some of it on a 3-digit DVM (both of which I still have, and
still work). It was a neutral grey colour, and circularly polarized.
I think the idea was that any light reflecting off the internal parts
would be attenuated by the polarization. I got the filter material
from Maplin's, who are still in business, but I
don't think they still
sell it.
I like playing with RED LEDs too and have a bunch of
clocks and things
to build and want to put such a filter/lens in front of them.
On the DVM, I also painted the PCB and jumper wires, etc., matt black.
--
John Honniball
coredump at gifford.co.uk
2 Oct
2 Oct
2:43 p.m.
John Honniball wrote:
I got the filter material
from Maplin's, who are still in business, but I don't think they still
sell it.
They stopped selling it ages ago, but Farnell still stock it:
http://uk.farnell.com/178186/optoelectronics/product.us0?sku=visualux-2711x…
A bit on the expensive side for what it is, but it does the job. I've been
using it with HP HDSP-2112 (green) 5x7 LED displays.
--
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/
3:04 p.m.
On Thu, Oct 02, 2008 at 10:43:05PM +0100, Philip Pemberton wrote:
John Honniball wrote:
Down for maintenance, unfortunately.
I got the filter material
from Maplin's, who are still in business, but I don't think they still
sell it.
They stopped selling it ages ago, but Farnell still stock it:
http://uk.farnell.com/178186/optoelectronics/product.us0?sku=visualux-2711x…
A bit on the expensive side for what it is, but it
does the job. I've been
using it with HP HDSP-2112 (green) 5x7 LED displays.
I have a few of those at home I got from a friend who worked at a place that
made avionics displays (when they cleared out buckets of old components).
I've never tried to talk to them, but I have the datasheet here. They look
interesting, but slightly complicated to talk to at the register level
(physical interfacing seems easy enough).
One idea I had for them was the date portion of a multi-time-zone clock
(we have several on the walls here out of necessity, and a desktop-sized
on seemed to be a good target). What have you been using yours for?
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 2-Oct-2008 at 21:50 Z
South Pole Station
PSC 468 Box 400 Temp -72.0 F (-57.8 C) Windchill -116.8 F (-82.7 C)
APO AP 96598 Wind 17.7 kts Grid 17 Barometer 674.9 mb (10821 ft)
Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html
3:34 p.m.
Ethan Dicks wrote:
Not really. It's straight 8-bit with RD/WR/CS/addressing. If you don't need to
read from the display, ignore the nRD line (tie it high), then tie nWR and nCS
together (to save an I/O line).
That leaves you with a requirement for 8 data lines, one write strobe, five
address lines, a reset line and the "flash register access" line (effectively
another address line). So that's 16 lines. I wanted to wire mine up to a PIC
microcontroller, so I needed to save a few more I/O lines.
The obvious solution (and the one I used) was to use a 74LS164 shift register
to handle the data pins. Shift the data in (8 clocks), set the address and
strobe nWR. Job done. If you need to save more I/O lines, add another shift
register to handle the address and nFL lines. That brings the count down to
four -- nWR/nCS, LS164_CLK, LS164_DATA, and RESET.
Startup is a piece of cake -- you write a single byte to the Mode register,
then you just write characters to the display RAM. User defined characters are
just as easy -- you write the character address to one register, then write
five bytes of character data to consecutive CGRAM addresses.
Down for maintenance, unfortunately.
Aye, usually from 10PM to 7AM UK time. The words "pain in the backside" spring
to mind...
A bit on the
expensive side for what it is, but it does the job. I've been
using it with HP HDSP-2112 (green) 5x7 LED displays.
I have a few of those at home I got from a friend who worked at a place that
made avionics displays (when they cleared out buckets of old components).
I've never tried to talk to them, but I have the datasheet here. They look
interesting, but slightly complicated to talk to at the register level
(physical interfacing seems easy enough). One idea I had for them was the date portion of a
multi-time-zone clock
(we have several on the walls here out of necessity, and a desktop-sized
on seemed to be a good target). What have you been using yours for?
I've only used one -- it's in a hand-held rev-counter I built for testing
motor speed controllers. I'm working on the power supply for it now --
basically it's a lithium-ion battery pack from a digital camera (Canon NB-5L,
from the new Ixus series, ?10) wired to a MAX1811
charge controller, an
MC34063 step-up converter (to get +5V) and a PIC micro that
acts as a battery
charge monitor. The hard part is building a connector for the battery...
--
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/
6:51 a.m.
Since one of the first computers I ever got my hands
on as a kid (Quest
Elf) happened to have TIL311 HEX displays, I've long been fascinated with
display technology of that vintage. I was poking around for images of
some of the related displays to the TIL311 and ran across a couple of
links with pictures and some history...
Hmm, if you are interested on then, TIL311's were used on FT-101ZD Yaesu
ham radios, as far as I know...
5704
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alexandre-listas＠e-secure.com.br -
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