Searching \ for '[EE:] Backlight levels' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=backlight+levels
Search entire site for: 'Backlight levels'.

Exact match. Not showing close matches.
PICList Thread
'[EE:] Backlight levels'
2005\06\11@062119 by Peter Onion

flavicon
face
Following on from my earlier question about light level measurements...

I now have a voltage going into a PIC's ADC that goes between 0V
(Darkness) to +4.5V (Sunlight). It's derived from a old selenium PV cell
I found and a logarithmic amplifier.  

So, my next problem is now should I use the ADC value to set the PWM
output that is controlling the LCD's LED back light.

Should the back light be BRIGHT at night and OFF in the day ?
Or DIM at night and during the day and BRIGHT at dawn+dusk ?

Is there any guidance where displays are used in safety critical systems
(*) where display brightness is controlled to achieve maximum
readability under varying lighting levels ?

Peter

(*) Not that my alarm clock will be a safety critical system of course !

2005\06\11@073828 by Jinx

face picon face
> Should the back light be BRIGHT at night and OFF in the day ?
> Or DIM at night and during the day and BRIGHT at dawn+dusk ?

A lot of what you're asking really depends on the user. IME displays
on things like bedside clocks are dim at night. Might just be psycho-
logical, knowing that a light is dimmer whilst you're trying to sleep

Thought about controlling the contrast too ?

> (*) Not that my alarm clock will be a safety critical system
> of course !

Oh, there are times when it's not safe to wake me up, like when
I've been up programming all night and crawled into bed in the
wee hours. You really really need a nothing phone call first thing
in the morning (but I do know about displaced anger - if I didn't
tell anyone to not wake me, it's my fault if they do)

2005\06\11@091745 by Bill & Pookie

picon face
Add a IR emitter/sensor and when you touch it with your finger at night it
could go bright.

Bill

----- Original Message -----
From: "Jinx" <spam_OUTjoecolquittTakeThisOuTspamclear.net.nz>
To: "Microcontroller discussion list - Public." <.....piclistKILLspamspam@spam@mit.edu>
Sent: Saturday, June 11, 2005 4:38 AM
Subject: Re: [EE:] Backlight levels


{Quote hidden}

> --

2005\06\11@095215 by Charles Linquist

flavicon
face
Why not just use a PLED display.  It is readable day and night, and
requires NO backlight.

Charles Linquist



Bill & Pookie wrote:
> Add a IR emitter/sensor and when you touch it with your finger at night it
> could go bright.
>
> Bill
>
> {Original Message removed}

2005\06\11@100021 by John J. McDonough

flavicon
face
I think this will depend on your application and your particular display.
Some LCDs are very hard to read without the backlight.  In those cases, you
may want the backlight to be quite bright in the daytime.  In general, you
don't want it to be too bright at night because you don't want to be looking
into the dark and seeing left over images of the display.

My car has LCDs for most of the dash, and it has a very bright backlight so
it is easy to read in all but the brightest sunlight.  However, when I turn
on the headlights, the display dims so as to prevent interfering with my
dark vision.

--McD

{Original Message removed}

2005\06\11@101240 by Charles Linquist

flavicon
face

I forgot to mention - PLEDS drive exactly like LCDs, cost less
than LCDs and draw 40mA max. I have even driven the whole display from
one PIC pin.

For a picture of my PLED clock, go to  http://www.charleslinquist.com/clock

The pictures really don't do the display justice, since this one still
has the polyethylene protective film over the display to protect the glass.

Charles Linquist

2005\06\11@102414 by Jan-Erik Soderholm

face picon face
Charles Linquist wrote :

> For a picture of my PLED clock, go to  http://www.charleslinquist.com/clock
>
> The pictures really don't do the display justice,...

But are still 1.4, 2.6 and 2.7 *MB each* in size !!

I'm pretty sure that 80-100 K would have been enough...

Jan-Erik.



2005\06\11@102535 by Peter Onion

flavicon
face
On Sat, 2005-06-11 at 07:10 -0700, Charles Linquist wrote:

> For a picture of my PLED clock, go to  http://www.charleslinquist.com/clock

I think mine looks nicer ;-)
www.btinternet.com/~Peter.Onion/PhaseData/p002140.jpg
Peter


2005\06\11@103700 by Charles Linquist

flavicon
face
Sorry for the big pics. I have really high bandwidth here at home,
and I forget that big files can be a problem for some.

And Peter, yours may look nicer, but my display costs $9, and I wrote
the code in about 15 minutes.  My whole clock consumes less than 50mA
display included.



Peter Onion wrote:
{Quote hidden}

2005\06\11@104907 by Peter Onion

flavicon
face
On Sat, 2005-06-11 at 07:34 -0700, Charles Linquist wrote:

> And Peter, yours may look nicer, but my display costs $9, and I wrote
> the code in about 15 minutes.  My whole clock consumes less than 50mA
> display included.

When did this become a contest ?

Peter

2005\06\11@113302 by David P Harris

picon face
Charles Linquist wrote:

> And Peter, yours may look nicer, but my display costs $9, .....

Where did you get one for $9?

David


2005\06\11@115121 by Charles Linquist

flavicon
face
David P Harris wrote:
> Charles Linquist wrote:
>
>> And Peter, yours may look nicer, but my display costs $9, .....
>
>
> Where did you get one for $9?
>
> David
>
>
http://www.onestopdisplays.net


You may have to pay a bit more, we buy them in 100's

Part # on the back of mine is OSD2002BYPNJB
20 chars X 2 lines.

Charles Linquist

2005\06\11@121514 by Spehro Pefhany

picon face
At 08:49 AM 6/11/2005 -0700, you wrote:
>David P Harris wrote:
>>Charles Linquist wrote:
>>
>>>And Peter, yours may look nicer, but my display costs $9, .....
>>
>>Where did you get one for $9?
>>David
>http://www.onestopdisplays.net
>
>
>You may have to pay a bit more, we buy them in 100's
>
>Part # on the back of mine is OSD2002BYPNJB
>20 chars X 2 lines.
>
>Charles Linquist

OLED/PLED lifetime is an issue in some applications. Especially at
elevated temperature, it can be surprisingly brief.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speffspamKILLspaminterlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
->> Inexpensive test equipment & parts http://search.ebay.com/_W0QQsassZspeff


2005\06\11@124655 by Charles Linquist

flavicon
face
We have a lot of these with well over a year on them.  Most have
been in room-temperature environments, but none have noticeable
degradation.

I watched one run in an environmental chamber at 60 degrees C for
one hour (along with the PIC, of course).  That was last summer.
Last I heard it was still working fine.
Lockheed-Martin buys a lot of them from us. Can't tell you what they
do with all of them, though!


Charles Linquist





Spehro Pefhany wrote:

{Quote hidden}

2005\06\11@135202 by Peter

picon face

On Sat, 11 Jun 2005, John J. McDonough wrote:

> on the headlights, the display dims so as to prevent interfering with my
> dark vision.

So if you do not turn on the headlights then the dash continues to shine
brightly ?

Peter

2005\06\11@154028 by olin piclist

face picon face
Spehro Pefhany wrote:
> OLED/PLED lifetime is an issue in some applications. Especially at
> elevated temperature, it can be surprisingly brief.

So what do "OLED" and "PLED" stand for?

*****************************************************************
Embed Inc, embedded system specialists in Littleton Massachusetts
(978) 742-9014, http://www.embedinc.com

2005\06\11@154134 by olin piclist

face picon face
Peter Onion wrote:
>> And Peter, yours may look nicer, but my display costs $9, and I wrote
>> the code in about 15 minutes.  My whole clock consumes less than 50mA
>> display included.
>
> When did this become a contest ?

Right about when you said "mine looks better than yours".

*****************************************************************
Embed Inc, embedded system specialists in Littleton Massachusetts
(978) 742-9014, http://www.embedinc.com

2005\06\11@155527 by Charles Linquist

flavicon
face

I think OLED stands for Organic Light Emitting Diode and
PLED stands for Polymeric Light Emitting Diode.

If someone knows more, please speak up!




Olin Lathrop wrote:
{Quote hidden}

2005\06\11@160945 by Peter Onion

flavicon
face
On Sat, 2005-06-11 at 15:41 -0400, Olin Lathrop wrote:
> Peter Onion wrote:
> >> And Peter, yours may look nicer, but my display costs $9, and I wrote
> >> the code in about 15 minutes.  My whole clock consumes less than 50mA
> >> display included.
> >
> > When did this become a contest ?
>
> Right about when you said "mine looks better than yours".

Except I didn't say that... I said "I think mine looks nicer ;-)"
Note I used "nicer" to try to avoid any potential "mine's better than
your's" that would enevitably followed, and I used a smiley to indicate
I was not being terribly serious about the comparison.

Peter

2005\06\11@161528 by William Chops Westfield

face picon face
On Jun 11, 2005, at 7:34 AM, Charles Linquist wrote:

> my display costs $9, and I wrote the code in about 15 minutes.

Ok, I'll bite.  Where does one get an LCD-compatible, low power PLED
display for $9?

>   My whole clock consumes less than 50mA display included.
>
That *is* a lot compared to pure LCD solutions (but they might consume
50mA just in the backlight.  And we're back on-topic...)

BillW

2005\06\11@162536 by Peter Onion

flavicon
face
On Sat, 2005-06-11 at 15:41 -0400, Olin Lathrop wrote:
> >
> > When did this become a contest ?
>
> Right about when you said "mine looks better than yours".

Please, if you are going to quote me, make an effort to get it right !

Peter



2005\06\11@163107 by Peter Onion

flavicon
face
On Sat, 2005-06-11 at 13:15 -0700, William Chops Westfield wrote:

> That *is* a lot compared to pure LCD solutions (but they might consume
> 50mA just in the backlight.  And we're back on-topic...)

The back light on mine takes about 85mA at 5V at 100% brightness.

Peter

2005\06\11@182717 by Spehro Pefhany

picon face
At 12:53 PM 6/11/2005 -0700, you wrote:

>I think OLED stands for Organic Light Emitting Diode and
>PLED stands for Polymeric Light Emitting Diode.
>
>If someone knows more, please speak up!

Yes, that's right (Polymer Light Emitting Diode is what I see for the
latter.

A very interesting display technology, already in use in some consumer
products (Pioneer had the first serious application that I know of, in
their colorful automotive stereo displays).

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
.....speffKILLspamspam.....interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com




2005\06\11@185912 by Philip Pemberton

face picon face
In message <EraseME42AB07FC.1080008spam_OUTspamTakeThisOuTlinquist.net>
         Charles Linquist <charlesspamspam_OUTlinquist.net> wrote:

> http://www.onestopdisplays.net
>
> You may have to pay a bit more, we buy them in 100's
>
> Part # on the back of mine is OSD2002BYPNJB
> 20 chars X 2 lines.

That is a seriously nice display.. Anyone know of a UK or European source for
OLED displays (either text or graphics type)?

I've been looking into using a display from a junked Samsung mobile phone,
but Samsung aren't too keen on providing me (or anyone else for that matter
it seems) with a copy of the datasheet for the controller IC or the display.
Well, not without a nice large (>1000 units) order anyway...

Later.
--
Phil.                              | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB,
@spam@philpemKILLspamspamphilpem.me.uk              | ViewFinder, 10BaseT Ethernet, 2-slice,
http://www.philpem.me.uk/          | 48xCD, ARCINv6c IDE, SCSI
... All wiyht.  Rho sritched mg kegtops awound?

2005\06\11@190421 by Philip Pemberton
face picon face
In message <KILLspamf27f3a1d1f758e6ff94227bc3cf3ddabKILLspamspammac.com>>          William "Chops" Westfield <RemoveMEwestfwTakeThisOuTspammac.com> wrote:

> That *is* a lot compared to pure LCD solutions (but they might consume
> 50mA just in the backlight.  And we're back on-topic...)

You think that's bad? I've got a Samsung VFD that pulls 200mA!

Speaking of which, anyone know of a source of reasonably cheap LCD-compatible
VFDs? I've got a few Samsung 20T202DA1Js, but I want more :)

Later.
--
Phil.                              | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB,
spamBeGonephilpemspamBeGonespamphilpem.me.uk              | ViewFinder, 10BaseT Ethernet, 2-slice,
http://www.philpem.me.uk/          | 48xCD, ARCINv6c IDE, SCSI
... My hard disk is full! Maybe I'll try this message section thing.

2005\06\11@214937 by Aaron

picon face
Philip Pemberton wrote:

>Speaking of which, anyone know of a source of reasonably cheap LCD-compatible
>VFDs? I've got a few Samsung 20T202DA1Js, but I want more :)
>  
>
I bought a couple extra VFDs from a piclister a while back when he did
an [AD] for an assortment of stuff.
Perhaps he'll read this and chime in if he has more...

Aaron

More... (looser matching)
- Last day of these posts
- In 2005 , 2006 only
- Today
- New search...