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[?] Displaying 16 analogue voltages (Graphic equaliser display style)

D

David Chapman

Jan 1, 1970
0
Greetings from the U.K.

I'm trying to find a suitable small(ish) display module (preferably
LCD) that can show graphically the relative levels of 16 simultaneously
available DC voltages, all in the range zero to +3 volts. I'd prefer
that the module wasn't any larger that about 4" wide and 2" high - its
front-to-back dimension is not critical.

I need a display arrangement that is capable of showing something like
the following, rather crude, 16-way bar-graph graphic image .....

X
X X X X
X X X X X X
X
X X X X X X X X X
X X
X X X X X X X X X X X X
X X X X

....so that with a quick glance it is immediately obvious
which of the 16 'channels' is producing the highest DC voltage. I don't
need to know the actual voltages, just which is/are the highest of them,
with each 'channel' voltage displayed by a 'lit' number of' (8-16)
graphic bars.

I have tried to find a ready-made audio-frequency band graphic display
module that could be modified to do this job but haven't, as yet, been
successful, so I'm now wondering if someone in this NG might know of
one, or be able to suggest a display manufacturer who can offer an
'off-the-shelf' module capable of doing this that DOES NOT require any
specially written custom software.

Since I'll probably only be needing a dozen or so of these modules
it's unlikely to be cost-effective to get something specially produced..

Any constructive suggestions and/or recommendations will be very much
appreciated.

TIA - Dave
 
J

Jamie

Jan 1, 1970
0
David said:
Greetings from the U.K.

I'm trying to find a suitable small(ish) display module (preferably
LCD) that can show graphically the relative levels of 16 simultaneously
available DC voltages, all in the range zero to +3 volts. I'd prefer
that the module wasn't any larger that about 4" wide and 2" high - its
front-to-back dimension is not critical.

I need a display arrangement that is capable of showing something like
the following, rather crude, 16-way bar-graph graphic image .....

X
X X X X
X X X X X X
X
X X X X X X X X X
X X
X X X X X X X X X X X X
X X X X

....so that with a quick glance it is immediately obvious
which of the 16 'channels' is producing the highest DC voltage. I don't
need to know the actual voltages, just which is/are the highest of them,
with each 'channel' voltage displayed by a 'lit' number of' (8-16)
graphic bars.

I have tried to find a ready-made audio-frequency band graphic display
module that could be modified to do this job but haven't, as yet, been
successful, so I'm now wondering if someone in this NG might know of
one, or be able to suggest a display manufacturer who can offer an
'off-the-shelf' module capable of doing this that DOES NOT require any
specially written custom software.

Since I'll probably only be needing a dozen or so of these modules
it's unlikely to be cost-effective to get something specially produced..

Any constructive suggestions and/or recommendations will be very much
appreciated.

TIA - Dave
Google,,

"Graphic LCD modules"
 
E

Ecnerwal

Jan 1, 1970
0
David Chapman said:
successful, so I'm now wondering if someone in this NG might know of
one, or be able to suggest a display manufacturer who can offer an
'off-the-shelf' module capable of doing this that DOES NOT require any
specially written custom software.

Since I'll probably only be needing a dozen or so of these modules
it's unlikely to be cost-effective to get something specially produced..

Any constructive suggestions and/or recommendations will be very much
appreciated.

I suspect the only practical way to do this for this many units involves
a general-purpose display, a microprocessor (preferably one with 16 or
more ADC inputs) and some "custom software" (which should not be too
terribly difficult to get written.) Either that or 16 (LED is more
likely than LCD, but you might get lucky) voltmeter circuits in parallel
and stacked side by side (ie, 16 displays side-by-side, not one display
with 16 sections.)

One old-fuddy-duddy solution would be the old (still in production, I
think?) LM3914 or 3915 (linear or log) from National Semiconductor,
wired into LED bars to make your display (you'd need 16, or 32 if you
wanted a lot of detail (more than 10 segments) to your bars - one reason
this sort of thing has mostly passed over to writing some code on a
microprocessor rather than buying chips that don't need code.) BUt that
assumes someone who can wire it up or design a PCB (which can be cost
effective even for 12 units - but may not be as cheap as you'd like to
go.)
 
H

hamilton

Jan 1, 1970
0
Greetings from the U.K.

I'm trying to find a suitable small(ish) display module (preferably
LCD) that can show graphically the relative levels of 16 simultaneously
available DC voltages, all in the range zero to +3 volts. I'd prefer
that the module wasn't any larger that about 4" wide and 2" high - its
front-to-back dimension is not critical.

A 4" LCD is really small for 16 channels.

If there is nothing else on the display, that would be 1/4" per column.

Unless your on top of it, it would be hard to see.
( unless the goal is to have a 16 channel display, just to say you have
a 16 channel display)

Ebay has lots of LCD displays and I am sure you will find one.

As has been mention, do you expect this to be a fully functional 16
channel display or is this a DIY project ??

h
 
G

Gerard Bok

Jan 1, 1970
0
I'm trying to find a suitable small(ish) display module (preferably
LCD) that can show graphically the relative levels of 16 simultaneously
available DC voltages, all in the range zero to +3 volts. I'd prefer
that the module wasn't any larger that about 4" wide and 2" high - its
front-to-back dimension is not critical.

So, you basically want an 8-band graphic equalizer display ?
 
H

hamilton

Jan 1, 1970
0
A 4" LCD is really small for 16 channels.

If there is nothing else on the display, that would be 1/4" per column.

Unless your on top of it, it would be hard to see.
( unless the goal is to have a 16 channel display, just to say you have
a 16 channel display)

Ebay has lots of LCD displays and I am sure you will find one.

As has been mention, do you expect this to be a fully functional 16
channel display or is this a DIY project ??

h

This is what I did with a large lcd display.

http://i890.photobucket.com/albums/ac107/donhamilton/lcd1.jpg

Display area is 8.5" x 2.9".

h
 
H

hamilton

Jan 1, 1970
0
There are LED bar driver chips, and little 10 LED or so display strips.
Put 16 next to each other, and use 16 of those driver chips (come in log and lin IIRC).
Of course I would use a 128x64 LCD graphics display myself.

I thought of that, but 128 wide /16 channels = 8 pixels per channnel.

With one pixel space between columns, thats 7 pixels wide.

Thats really small and up close.

h
 
H

hamilton

Jan 1, 1970
0
Very nicely done!
I dunno how much resolution the OP wants, this would only give 25%.
And no space for numbering.

If he only wants to know the biggest then he only needs a 2 digit display
from 0-15 :)
Yes, the OP did state that he wanted a display of just the relative values.

I hope the OP is still around. :-\

h
 
D

David Chapman

Jan 1, 1970
0
..
I hope the OP is still around. :-\

Yes I am, and I'm most appreciative of the various suggestions that
have already been made.

I certainly did consider the 3904 + 8-LED bar x 16 approach, but
rejected it since it would be a LOT 'thirstier' and physically much
larger than any LCD solution.

After reading all of the responses to my posting, I'm sure that an LCD
design is the way forward so I'll now start looking for a friendly 'PIC
expert' to write me a suitable bit of code ;-).

My thanks to all the contributors. I'm most grateful.

ATB - Dave
 
H

hamilton

Jan 1, 1970
0
.

Yes I am, and I'm most appreciative of the various suggestions that have
already been made.

I certainly did consider the 3904 + 8-LED bar x 16 approach, but
rejected it since it would be a LOT 'thirstier' and physically much
larger than any LCD solution.

After reading all of the responses to my posting, I'm sure that an LCD
design is the way forward so I'll now start looking for a friendly 'PIC
expert' to write me a suitable bit of code ;-).

My thanks to all the contributors. I'm most grateful.

ATB - Dave

By LCD do you mean 16x2, 16x4 or 128x64 ?? ( charactor or graphic ?? )

A 16 char LCD is about 2" wide, your original request was for a 4" wide
display.

In your original request was for a few units, how many is a few ?

Are you looking at doing any of your own assembly or for a completed unit ?

thanks

hamilton
 
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