Asking here in the hope someone has come across this and may have an
answer.

Car interior lights have an auto 'dimmer'. They do a graceful fade in and
fade out when switched on and off. On a Merc. Owner wanted some slightly
brighter lights so changed from tungsten to LED. The auto system still
does a graceful fade out - but sort of leaps to on, rather than fading up.
Later Mercs have got LED lighting which does fade in and out OK - but it's
not just a case of changing the module which on the later cars is part of
other things too.

On this model the module is stand alone, so would be possible to modify it.

--
*To be intoxicated is to feel sophisticated, but not be able to say it.

Dave Plowman London SW
To e-mail, change noise into sound.

On Thursday, 17 November 2016 15:24:55 UTC, Dave Plowman (News) wrote:
Asking here in the hope someone has come across this and may have an
answer.

Car interior lights have an auto 'dimmer'. They do a graceful fade in and
fade out when switched on and off. On a Merc. Owner wanted some slightly
brighter lights so changed from tungsten to LED. The auto system still
does a graceful fade out - but sort of leaps to on, rather than fading up.
Later Mercs have got LED lighting which does fade in and out OK - but it's
not just a case of changing the module which on the later cars is part of
other things too.

On this model the module is stand alone, so would be possible to modify it.


Why don't you replace the traic ;-)

In article ,
whisky-dave wrote:
On Thursday, 17 November 2016 15:24:55 UTC, Dave Plowman (News) wrote:
Asking here in the hope someone has come across this and may have an
answer.

Car interior lights have an auto 'dimmer'. They do a graceful fade in
and fade out when switched on and off. On a Merc. Owner wanted some
slightly brighter lights so changed from tungsten to LED. The auto
system still does a graceful fade out - but sort of leaps to on, rather
than fading up. Later Mercs have got LED lighting which does fade in
and out OK - but it's not just a case of changing the module which on
the later cars is part of other things too.

On this model the module is stand alone, so would be possible to modify
it.


Why don't you replace the traic ;-)

'cos car electrics are dc

--
from KT24 in Surrey, England

On Thursday, 17 November 2016 18:28:43 UTC, charles wrote:
In article ,
whisky-dave wrote:
On Thursday, 17 November 2016 15:24:55 UTC, Dave Plowman (News) wrote:

Asking here in the hope someone has come across this and may have an
answer.

Car interior lights have an auto 'dimmer'. They do a graceful fade in
and fade out when switched on and off. On a Merc. Owner wanted some
slightly brighter lights so changed from tungsten to LED. The auto
system still does a graceful fade out - but sort of leaps to on, rather
than fading up. Later Mercs have got LED lighting which does fade in
and out OK - but it's not just a case of changing the module which on
the later cars is part of other things too.

On this model the module is stand alone, so would be possible to modify
it.


Why don't you replace the traic ;-)

'cos car electrics are dc

Except for Ford model T.


NT

wrote in message
...
On Thursday, 17 November 2016 18:28:43 UTC, charles wrote:
'cos car electrics are dc

Except for Ford model T.

Is there any fundamental reason why early pre-electronic car electrics were
DC and not AC?

On 17/11/16 18:47, NY wrote:


wrote in message
...
On Thursday, 17 November 2016 18:28:43 UTC, charles wrote:
'cos car electrics are dc

Except for Ford model T.

Is there any fundamental reason why early pre-electronic car electrics
were DC and not AC?

Yes.


--
Truth welcomes investigation because truth knows investigation will lead
to converts. It is deception that uses all the other techniques.

NY wrote
wrote
charles wrote

'cos car electrics are dc

Except for Ford model T.

Is there any fundamental reason why early pre-electronic
car electrics were DC and not AC?

Yes, the battery. No way of powering
the lights with the engine not running.

In article ,
wrote:
On Thursday, 17 November 2016 18:28:43 UTC, charles wrote:
In article ,
whisky-dave wrote:
On Thursday, 17 November 2016 15:24:55 UTC, Dave Plowman (News)
wrote:

Asking here in the hope someone has come across this and may have
an answer.

Car interior lights have an auto 'dimmer'. They do a graceful fade
in and fade out when switched on and off. On a Merc. Owner wanted
some slightly brighter lights so changed from tungsten to LED. The
auto system still does a graceful fade out - but sort of leaps to
on, rather than fading up. Later Mercs have got LED lighting which
does fade in and out OK - but it's not just a case of changing the
module which on the later cars is part of other things too.

On this model the module is stand alone, so would be possible to
modify it.


Why don't you replace the traic ;-)

'cos car electrics are dc

Except for Ford model T.

not very relevant in the contexct of a Merc's interior lights.

--
from KT24 in Surrey, England

In article ,
charles wrote:
Why don't you replace the traic ;-)

'cos car electrics are dc

Doubt our Dave knows the difference between a triac and SCR. ;-)

--
*You're just jealous because the voices only talk to me *

Dave Plowman London SW
To e-mail, change noise into sound.

On Friday, 18 November 2016 00:31:41 UTC, Dave Plowman (News) wrote:
In article ,
charles wrote:
Why don't you replace the traic ;-)

'cos car electrics are dc

Doubt our Dave knows the difference between a triac and SCR. ;-)

Then why did yuo tell me to replace the triac in my dimmer ?

In article ,
whisky-dave wrote:
On Friday, 18 November 2016 00:31:41 UTC, Dave Plowman (News) wrote:
In article ,
charles wrote:
Why don't you replace the traic ;-)

'cos car electrics are dc

Doubt our Dave knows the difference between a triac and SCR. ;-)

Then why did yuo tell me to replace the triac in my dimmer ?

Thanks for confirming my worse fears.

--
*If love is blind, why is lingerie so popular?

Dave Plowman London SW
To e-mail, change noise into sound.

On Thursday, 17 November 2016 15:24:55 UTC, Dave Plowman (News) wrote:
Asking here in the hope someone has come across this and may have an
answer.

Car interior lights have an auto 'dimmer'. They do a graceful fade in and
fade out when switched on and off. On a Merc. Owner wanted some slightly
brighter lights so changed from tungsten to LED. The auto system still
does a graceful fade out - but sort of leaps to on, rather than fading up.
Later Mercs have got LED lighting which does fade in and out OK - but it's
not just a case of changing the module which on the later cars is part of
other things too.

On this model the module is stand alone, so would be possible to modify it.

Probably. I can't imagine it being worth doing. Tungstens have zero output at near half power, LEDs have zero output near zero power, hence the behaviour you see.


NT

In article ,
wrote:
On Thursday, 17 November 2016 15:24:55 UTC, Dave Plowman (News) wrote:
Asking here in the hope someone has come across this and may have an
answer.

Car interior lights have an auto 'dimmer'. They do a graceful fade in
and fade out when switched on and off. On a Merc. Owner wanted some
slightly brighter lights so changed from tungsten to LED. The auto
system still does a graceful fade out - but sort of leaps to on,
rather than fading up. Later Mercs have got LED lighting which does
fade in and out OK - but it's not just a case of changing the module
which on the later cars is part of other things too.

On this model the module is stand alone, so would be possible to
modify it.

Probably. I can't imagine it being worth doing.

Not up to you - or me, come to that. It's something the owner wants.

Tungstens have zero output at near half power, LEDs have zero output
near zero power, hence the behaviour you see.

Did you miss the bit where newer cars manage it with LEDs?

--
*Sleep with a photographer and watch things develop

Dave Plowman London SW
To e-mail, change noise into sound.

On Friday, 18 November 2016 00:21:33 UTC, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Thursday, 17 November 2016 15:24:55 UTC, Dave Plowman (News) wrote:

Car interior lights have an auto 'dimmer'. They do a graceful fade in
and fade out when switched on and off. On a Merc. Owner wanted some
slightly brighter lights so changed from tungsten to LED. The auto
system still does a graceful fade out - but sort of leaps to on,
rather than fading up. Later Mercs have got LED lighting which does
fade in and out OK - but it's not just a case of changing the module
which on the later cars is part of other things too.

On this model the module is stand alone, so would be possible to
modify it.

Probably. I can't imagine it being worth doing.

Not up to you - or me, come to that. It's something the owner wants.

Tungstens have zero output at near half power, LEDs have zero output
near zero power, hence the behaviour you see.

Did you miss the bit where newer cars manage it with LEDs?

No. At the risk of stating the obvious if an analogue fade circuit starts & stops at half power there's a good chance it can be modded by changing a set point.

There isn't really any useful answer to your question unless you can find a stand alone retrofit module or you post the schematic.


NT

In article ,
wrote:
Did you miss the bit where newer cars manage it with LEDs?

No. At the risk of stating the obvious if an analogue fade circuit
starts & stops at half power there's a good chance it can be modded by
changing a set point.

I don't know what the start point is. All I know is it did what looked to
be a perfect fade up and fade down with tungsten.

There isn't really any useful answer to your question unless you can
find a stand alone retrofit module or you post the schematic.

Very unlikely to find a schematic of such a proprietary part. But do have
the connections to it from the car wiring diagram.

I have slung together a lash up using a voltage reg to give a soft start
and a simple RC for the fade out. With a small tungsten, it gives a pretty
good fade in and out. With a LED, it exhibits the effect I noted. It sort
of comes on at about half brightness then fades up to full. It fades out
perfectly. Almost as if the LED had a 'strike' current.

--
*I wish the buck stopped here. I could use a few.

Dave Plowman London SW
To e-mail, change noise into sound.

On 18/11/2016 11:06, Dave Plowman (News) wrote:

I have slung together a lash up using a voltage reg to give a soft start
and a simple RC for the fade out. With a small tungsten, it gives a pretty
good fade in and out. With a LED, it exhibits the effect I noted. It sort
of comes on at about half brightness then fades up to full. It fades out
perfectly. Almost as if the LED had a 'strike' current.


I still think you need to PWM it to get the effect you want, simple
voltage control is unlikely to achieve that.

On Friday, November 18, 2016 at 11:09:53 AM UTC, Dave Plowman (News) wrote:
In article ,
Almost as if the LED had a 'strike' current.

`Strike` voltage, bit over 3V usually for white blue and true green LEDs, less than 2 for older colours.


--
*I wish the buck stopped here. I could use a few.

Dave Plowman London SW
To e-mail, change noise into sound.

This sounds like a simple circuit charging up a capacitor to bias on a
transistor. The problem probably is that the settings used assume a lower
resistance load than the led. It depends if its using someform of feedback
to achieve the more smooth gradual illumination.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Dave Plowman (News)" wrote in message
...
Asking here in the hope someone has come across this and may have an
answer.

Car interior lights have an auto 'dimmer'. They do a graceful fade in and
fade out when switched on and off. On a Merc. Owner wanted some slightly
brighter lights so changed from tungsten to LED. The auto system still
does a graceful fade out - but sort of leaps to on, rather than fading up.
Later Mercs have got LED lighting which does fade in and out OK - but it's
not just a case of changing the module which on the later cars is part of
other things too.

On this model the module is stand alone, so would be possible to modify
it.

--
*To be intoxicated is to feel sophisticated, but not be able to say it.

Dave Plowman London SW
To e-mail, change noise into sound.

Brian Gaff wrote:

This sounds like a simple circuit charging up a capacitor to bias on a
transistor. The problem probably is that the settings used assume a lower
resistance load than the led. It depends if its using someform of feedback
to achieve the more smooth gradual illumination.
Brian

Nowadays such things are more often done with a microprocessor. It is
probably actually cheaper than the high value stable capacitor you would
need tor the analogue timer. My bathroom fan does its timer this way,
making modifying its behaviour a work in progress.


--

Roger Hayter

In article ,
Roger Hayter wrote:
Brian Gaff wrote:

This sounds like a simple circuit charging up a capacitor to bias on a
transistor. The problem probably is that the settings used assume a
lower resistance load than the led. It depends if its using someform
of feedback to achieve the more smooth gradual illumination.
Brian

Nowadays such things are more often done with a microprocessor. It is
probably actually cheaper than the high value stable capacitor you would
need tor the analogue timer. My bathroom fan does its timer this way,
making modifying its behaviour a work in progress.

Could well be. Have looked to see if there are any dedicated chips for
this job - but so far no luck.

--
*If we weren't meant to eat animals, why are they made of meat?

Dave Plowman London SW
To e-mail, change noise into sound.

On 18/11/2016 00:24, Dave Plowman (News) wrote:
In article ,
Roger Hayter wrote:
Brian Gaff wrote:

This sounds like a simple circuit charging up a capacitor to bias on a
transistor. The problem probably is that the settings used assume a
lower resistance load than the led. It depends if its using someform
of feedback to achieve the more smooth gradual illumination.
Brian

Nowadays such things are more often done with a microprocessor. It is
probably actually cheaper than the high value stable capacitor you would
need tor the analogue timer. My bathroom fan does its timer this way,
making modifying its behaviour a work in progress.

Could well be. Have looked to see if there are any dedicated chips for
this job - but so far no luck.


Our car has this also, had a look at the circuit board and as expected
it's just a COB. The one in ours also has canbus as well as power, so
it's at least possible the dimming is done by the BCM.

I dare say that anyone familiar with a PIC could program one up to do
the job of a basic fade in/out in a few minutes.
Anyone on here want to offer?

On 17/11/2016 15:24, Dave Plowman (News) wrote:
Asking here in the hope someone has come across this and may have an
answer.

Car interior lights have an auto 'dimmer'. They do a graceful fade in and
fade out when switched on and off. On a Merc. Owner wanted some slightly
brighter lights so changed from tungsten to LED. The auto system still
does a graceful fade out - but sort of leaps to on, rather than fading up.
Later Mercs have got LED lighting which does fade in and out OK - but it's
not just a case of changing the module which on the later cars is part of
other things too.

On this model the module is stand alone, so would be possible to modify it.


I wonder if the tungsten module is doing it by varying the voltage
whereas the LED one is PWM/current control?
Should be easy to check and then maybe knock up a voltage controlled
PWM? I note there are a few old school 555 designs for that

On 18/11/16 12:25, Lee wrote:
On 17/11/2016 15:24, Dave Plowman (News) wrote:
Asking here in the hope someone has come across this and may have an
answer.

Car interior lights have an auto 'dimmer'. They do a graceful fade in and
fade out when switched on and off. On a Merc. Owner wanted some slightly
brighter lights so changed from tungsten to LED. The auto system still
does a graceful fade out - but sort of leaps to on, rather than fading
up.
Later Mercs have got LED lighting which does fade in and out OK - but
it's
not just a case of changing the module which on the later cars is part of
other things too.

On this model the module is stand alone, so would be possible to
modify it.


I wonder if the tungsten module is doing it by varying the voltage
whereas the LED one is PWM/current control?
Should be easy to check and then maybe knock up a voltage controlled
PWM? I note there are a few old school 555 designs for that


I could, but I wont. Not after Plow**** claimed I had never designed
anything in my life in practice.

He's such a ****ing expert, he can do it.


--
If you tell a lie big enough and keep repeating it, people will
eventually come to believe it. The lie can be maintained only for such
time as the State can shield the people from the political, economic
and/or military consequences of the lie. It thus becomes vitally
important for the State to use all of its powers to repress dissent, for
the truth is the mortal enemy of the lie, and thus by extension, the
truth is the greatest enemy of the State.

Joseph Goebbels

In article ,
Lee wrote:
On 17/11/2016 15:24, Dave Plowman (News) wrote:
Asking here in the hope someone has come across this and may have an
answer.

Car interior lights have an auto 'dimmer'. They do a graceful fade in
and fade out when switched on and off. On a Merc. Owner wanted some
slightly brighter lights so changed from tungsten to LED. The auto
system still does a graceful fade out - but sort of leaps to on,
rather than fading up. Later Mercs have got LED lighting which does
fade in and out OK - but it's not just a case of changing the module
which on the later cars is part of other things too.

On this model the module is stand alone, so would be possible to
modify it.


I wonder if the tungsten module is doing it by varying the voltage
whereas the LED one is PWM/current control?

That's a good guess, I'd say.

Should be easy to check and then maybe knock up a voltage controlled
PWM? I note there are a few old school 555 designs for that

Not seen any that do the fade in fade out when powered up and down, though.

As was said, it might be easier to use a microprocessor for this. Above my
pay grade, sadly.

--
*I wished the buck stopped here, as I could use a few*

Dave Plowman London SW
To e-mail, change noise into sound.

On Friday, November 18, 2016 at 2:00:13 PM UTC, Dave Plowman (News) wrote:
In article ,
Lee wrote:
On 17/11/2016 15:24, Dave Plowman (News) wrote:
Asking here in the hope someone has come across this and may have an
answer.

Car interior lights have an auto 'dimmer'. They do a graceful fade in
and fade out when switched on and off. On a Merc. Owner wanted some
slightly brighter lights so changed from tungsten to LED. The auto
system still does a graceful fade out - but sort of leaps to on,
rather than fading up. Later Mercs have got LED lighting which does
fade in and out OK - but it's not just a case of changing the module
which on the later cars is part of other things too.

On this model the module is stand alone, so would be possible to
modify it.


I wonder if the tungsten module is doing it by varying the voltage
whereas the LED one is PWM/current control?

That's a good guess, I'd say.

Should be easy to check and then maybe knock up a voltage controlled
PWM? I note there are a few old school 555 designs for that

Not seen any that do the fade in fade out when powered up and down, though.

As was said, it might be easier to use a microprocessor for this. Above my
pay grade, sadly.

PWM won`t quite make it to zero theres a slight step down to zero , but usually close enough, current control is usually smoother.

Arduino and output transistor, cheaper than building it in discretes

http://arduino.stackexchange.com/que...h-arduino-nano

http://www.ebay.co.uk/itm/like/262459320226



--
*I wished the buck stopped here, as I could use a few*

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Adam Aglionby wrote:
Should be easy to check and then maybe knock up a voltage controlled
PWM? I note there are a few old school 555 designs for that

Not seen any that do the fade in fade out when powered up and down,
though.

As was said, it might be easier to use a microprocessor for this.
Above my pay grade, sadly.

PWM won`t quite make it to zero theres a slight step down to zero , but
usually close enough, current control is usually smoother.

Arduino and output transistor, cheaper than building it in discretes

http://arduino.stackexchange.com/que...h-arduino-nano

http://www.ebay.co.uk/itm/like/262459320226

Thanks, Adam, I'll pass this on.

--
*Can atheists get insurance for acts of God? *

Dave Plowman London SW
To e-mail, change noise into sound.