Slow fade-in circuit

On Wednesday, September 23, 2020 at 4:20:28 AM UTC-4, rhor...@gmail.com wrote:
> On Wednesday, September 23, 2020 at 12:39:09 AM UTC-5, whit3rd wrote:
> > LED fixtures that take 110VAC are all different types and designs, and while some come with dimmer 
> > options, not all do.
> 
> I am aware, thanks.  Non-dimmable bulbs do not work well with dimmers.  'Big surprise.  It is easy enough to buy dimmable LED bulbs.

Even dimmable LED bulbs don't always respond well to the standard triac/SCR type dimmers.  I bought an LED ceiling light along with a dimmer which was listed on the LED package as "compatible".  It works very badly, requiring the handle to move half it's range before the LED comes on at all, then the brightness is irregular with movement of the control and even varies a bit while the handle is still.  

In your application this will mostly not be an issue although you may see some flickering of the light as it dims. 


> > There are also different types of "12VDC" lamps, none of which (to my knowledge) 
> > is a simple LED.
> Many are.  As a matter of fact, I just installed a 12V wifi dimmer on my 12V LED strips lining the stair step in my theater.  I already have wifi control of the ceiling lights.  I just need them to come up slowly when turned on.  A VCO feeding a Triac / Diac pair should work, but I am unsure of details.
> 
> > You could, however, operate a servo motor to lower a shade over a panel, or 
> > rotate a polarizer, i.e. ignore the electronic range of such devices by... ignoring the electronic parts.
> No, no, no.  That is going off the rails.  All I need is a circuit with a slowly charging capacitor that changes the duty cycle of a Triac.

Good luck with that.  I believe I would use an 8 pin MCU which is aware of the line voltage as well as the phase.  A problem with many dimmers is the poor response to line voltage changes, but then you won't be using it in a dimmed mode.  The dimming will be purely transient coming up to full brightness in a few seconds. 

-- 

  Rick C.

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  - Tesla referral code - https://ts.la/richard11209

On Wednesday, September 23, 2020 at 5:39:52 AM UTC-4, Miguel Giménez wrote:
> El 23/09/2020 a las 6:08, rhor...@gmail.com escribió:
> > I need a simple circuit design for a slow fade-in AC dimmer.  In a dark theater, suddenly turning on the lights is a somewhat unpleasant experience.  I want a simple circuit compatible with 110 volt dimmable LED lights that will slowly ramp the light output over a period of about 5 seconds or so.  I have found a number of simple designs that would work for 12VDC LEDs, but none for 110VAC dimmable LED lights.
> > 
> 
> We did that many years ago with a small microcontroller and a triac, it 
> worked very well. The application was sunrise/sunset simulation in a 
> city small-scale model.

Bet you weren't using LED lights.  LEDs often flicker a bit when used on triac type dimmers.  I've read some articles about why this happens, but don't recall the reasons.  I think it comes down to the fact that LED supplies don't naturally respond to changes in the AC duty cycle.  So they have to measure the phase angle of the triac turn on and adjust the dimming from that.  Since the full AC cycle is not presented to the supply the duty cycle is horrible.  

For all practical purposes triac type dimming is deprecated for use with LEDs.  Direct control via a low voltage or resistance is the recommended method.  But then this is an extra wire and a low voltage extra wire which must be run separately... in other words, a PITA.  

-- 

  Rick C.

  + Get 1,000 miles of free Supercharging
  + Tesla referral code - https://ts.la/richard11209

On 9/24/2020 9:45 AM, Ricketty C wrote:
> On Wednesday, September 23, 2020 at 4:20:28 AM UTC-4, rhor...@gmail.com wrote:
>> On Wednesday, September 23, 2020 at 12:39:09 AM UTC-5, whit3rd wrote:
>>> LED fixtures that take 110VAC are all different types and designs, and while some come with dimmer
>>> options, not all do.
>>
>> I am aware, thanks.  Non-dimmable bulbs do not work well with dimmers.  'Big surprise.  It is easy enough to buy dimmable LED bulbs.
> 
> Even dimmable LED bulbs don't always respond well to the standard triac/SCR type dimmers.  I bought an LED ceiling light along with a dimmer which was listed on the LED package as "compatible".  It works very badly, requiring the handle to move half it's range before the LED comes on at all, then the brightness is irregular with movement of the control and even varies a bit while the handle is still.
> 
> In your application this will mostly not be an issue although you may see some flickering of the light as it dims.
> 
> 
>>> There are also different types of "12VDC" lamps, none of which (to my knowledge)
>>> is a simple LED.
>> Many are.  As a matter of fact, I just installed a 12V wifi dimmer on my 12V LED strips lining the stair step in my theater.  I already have wifi control of the ceiling lights.  I just need them to come up slowly when turned on.  A VCO feeding a Triac / Diac pair should work, but I am unsure of details.
>>
>>> You could, however, operate a servo motor to lower a shade over a panel, or
>>> rotate a polarizer, i.e. ignore the electronic range of such devices by... ignoring the electronic parts.
>> No, no, no.  That is going off the rails.  All I need is a circuit with a slowly charging capacitor that changes the duty cycle of a Triac.
> 
> Good luck with that.  I believe I would use an 8 pin MCU which is aware of the line voltage as well as the phase.  A problem with many dimmers is the poor response to line voltage changes, but then you won't be using it in a dimmed mode.  The dimming will be purely transient coming up to full brightness in a few seconds.
> 

OP said he wants a circuit considerably smaller than a matchbox.

I think the clearances required for 110VAC operation and the voltage 
ratings of the components you'll need to build a trailing-edge dimmer, 
say, are going to make that a problem if it all has to fit on a single 
board.

Why the circuit MUST fit inside the bell-housing of a ceiling fan is 
unclear if this is a one-off personal application, sounds more like 
someone trying to integrate something for sale.

Would recommend hiring an engineer in that case.

On Thursday, September 24, 2020 at 10:58:50 AM UTC-4, bitrex wrote:
> On 9/24/2020 9:45 AM, Ricketty C wrote:
> > On Wednesday, September 23, 2020 at 4:20:28 AM UTC-4, rhor...@gmail.com wrote:
> >> On Wednesday, September 23, 2020 at 12:39:09 AM UTC-5, whit3rd wrote:
> >>> LED fixtures that take 110VAC are all different types and designs, and while some come with dimmer
> >>> options, not all do.
> >>
> >> I am aware, thanks.  Non-dimmable bulbs do not work well with dimmers.  'Big surprise.  It is easy enough to buy dimmable LED bulbs.
> > 
> > Even dimmable LED bulbs don't always respond well to the standard triac/SCR type dimmers.  I bought an LED ceiling light along with a dimmer which was listed on the LED package as "compatible".  It works very badly, requiring the handle to move half it's range before the LED comes on at all, then the brightness is irregular with movement of the control and even varies a bit while the handle is still.
> > 
> > In your application this will mostly not be an issue although you may see some flickering of the light as it dims.
> > 
> > 
> >>> There are also different types of "12VDC" lamps, none of which (to my knowledge)
> >>> is a simple LED.
> >> Many are.  As a matter of fact, I just installed a 12V wifi dimmer on my 12V LED strips lining the stair step in my theater.  I already have wifi control of the ceiling lights.  I just need them to come up slowly when turned on.  A VCO feeding a Triac / Diac pair should work, but I am unsure of details.
> >>
> >>> You could, however, operate a servo motor to lower a shade over a panel, or
> >>> rotate a polarizer, i.e. ignore the electronic range of such devices by... ignoring the electronic parts.
> >> No, no, no.  That is going off the rails.  All I need is a circuit with a slowly charging capacitor that changes the duty cycle of a Triac.
> > 
> > Good luck with that.  I believe I would use an 8 pin MCU which is aware of the line voltage as well as the phase.  A problem with many dimmers is the poor response to line voltage changes, but then you won't be using it in a dimmed mode.  The dimming will be purely transient coming up to full brightness in a few seconds.
> > 
> 
> OP said he wants a circuit considerably smaller than a matchbox.
> 
> I think the clearances required for 110VAC operation and the voltage 
> ratings of the components you'll need to build a trailing-edge dimmer, 
> say, are going to make that a problem if it all has to fit on a single 
> board.
> 
> Why the circuit MUST fit inside the bell-housing of a ceiling fan is 
> unclear if this is a one-off personal application, sounds more like 
> someone trying to integrate something for sale.
> 
> Would recommend hiring an engineer in that case.

A 120 VAC circuit does not require any special clearances.  That would be for isolating high voltage and low voltage circuits.  This entire design can be treated as a high voltage circuit.  

It has to go in the housing of the fan so it isn't stuck someplace even more crowded like the wall switch box.  That said, if a commercial product would do the job, but not fit in a match box (as if that were remotely likely) it would be very reasonable to add a box next to the fan mounting box which could then house a commercial circuit more easily.  

But it does seem reasonable to simply add a wall dimmer switch in place of the toggle switch.  But maybe the lights are being brought up automatically by the "theater" system rather than manually switched on.  The automatic effect would be nice though.  

-- 

  Rick C.

  -- Get 1,000 miles of free Supercharging
  -- Tesla referral code - https://ts.la/richard11209

On 9/24/2020 11:35 AM, Ricketty C wrote:
> On Thursday, September 24, 2020 at 10:58:50 AM UTC-4, bitrex wrote:
>> On 9/24/2020 9:45 AM, Ricketty C wrote:
>>> On Wednesday, September 23, 2020 at 4:20:28 AM UTC-4, rhor...@gmail.com wrote:
>>>> On Wednesday, September 23, 2020 at 12:39:09 AM UTC-5, whit3rd wrote:
>>>>> LED fixtures that take 110VAC are all different types and designs, and while some come with dimmer
>>>>> options, not all do.
>>>>
>>>> I am aware, thanks.  Non-dimmable bulbs do not work well with dimmers.  'Big surprise.  It is easy enough to buy dimmable LED bulbs.
>>>
>>> Even dimmable LED bulbs don't always respond well to the standard triac/SCR type dimmers.  I bought an LED ceiling light along with a dimmer which was listed on the LED package as "compatible".  It works very badly, requiring the handle to move half it's range before the LED comes on at all, then the brightness is irregular with movement of the control and even varies a bit while the handle is still.
>>>
>>> In your application this will mostly not be an issue although you may see some flickering of the light as it dims.
>>>
>>>
>>>>> There are also different types of "12VDC" lamps, none of which (to my knowledge)
>>>>> is a simple LED.
>>>> Many are.  As a matter of fact, I just installed a 12V wifi dimmer on my 12V LED strips lining the stair step in my theater.  I already have wifi control of the ceiling lights.  I just need them to come up slowly when turned on.  A VCO feeding a Triac / Diac pair should work, but I am unsure of details.
>>>>
>>>>> You could, however, operate a servo motor to lower a shade over a panel, or
>>>>> rotate a polarizer, i.e. ignore the electronic range of such devices by... ignoring the electronic parts.
>>>> No, no, no.  That is going off the rails.  All I need is a circuit with a slowly charging capacitor that changes the duty cycle of a Triac.
>>>
>>> Good luck with that.  I believe I would use an 8 pin MCU which is aware of the line voltage as well as the phase.  A problem with many dimmers is the poor response to line voltage changes, but then you won't be using it in a dimmed mode.  The dimming will be purely transient coming up to full brightness in a few seconds.
>>>
>>
>> OP said he wants a circuit considerably smaller than a matchbox.
>>
>> I think the clearances required for 110VAC operation and the voltage
>> ratings of the components you'll need to build a trailing-edge dimmer,
>> say, are going to make that a problem if it all has to fit on a single
>> board.
>>
>> Why the circuit MUST fit inside the bell-housing of a ceiling fan is
>> unclear if this is a one-off personal application, sounds more like
>> someone trying to integrate something for sale.
>>
>> Would recommend hiring an engineer in that case.
> 
> A 120 VAC circuit does not require any special clearances.  That would be for isolating high voltage and low voltage circuits.  This entire design can be treated as a high voltage circuit.

Enforcing some minimum distances between hot and neutral traces and any 
exposed contacts with hot and neutral on them seems like a good 
idea...resistors that are going to see the full rectified line voltage 
across them at some point should be rated for 350 volts

> It has to go in the housing of the fan so it isn't stuck someplace even more crowded like the wall switch box.  That said, if a commercial product would do the job, but not fit in a match box (as if that were remotely likely) it would be very reasonable to add a box next to the fan mounting box which could then house a commercial circuit more easily.
> 
> But it does seem reasonable to simply add a wall dimmer switch in place of the toggle switch.  But maybe the lights are being brought up automatically by the "theater" system rather than manually switched on.  The automatic effect would be nice though.
> 

It's a weird requirement for a one-off

On Thursday, September 24, 2020 at 12:02:33 PM UTC-4, bitrex wrote:
> On 9/24/2020 11:35 AM, Ricketty C wrote:
> > On Thursday, September 24, 2020 at 10:58:50 AM UTC-4, bitrex wrote:
> >> On 9/24/2020 9:45 AM, Ricketty C wrote:
> >>> On Wednesday, September 23, 2020 at 4:20:28 AM UTC-4, rhor...@gmail.com wrote:
> >>>> On Wednesday, September 23, 2020 at 12:39:09 AM UTC-5, whit3rd wrote:
> >>>>> LED fixtures that take 110VAC are all different types and designs, and while some come with dimmer
> >>>>> options, not all do.
> >>>>
> >>>> I am aware, thanks.  Non-dimmable bulbs do not work well with dimmers.  'Big surprise.  It is easy enough to buy dimmable LED bulbs.
> >>>
> >>> Even dimmable LED bulbs don't always respond well to the standard triac/SCR type dimmers.  I bought an LED ceiling light along with a dimmer which was listed on the LED package as "compatible".  It works very badly, requiring the handle to move half it's range before the LED comes on at all, then the brightness is irregular with movement of the control and even varies a bit while the handle is still.
> >>>
> >>> In your application this will mostly not be an issue although you may see some flickering of the light as it dims.
> >>>
> >>>
> >>>>> There are also different types of "12VDC" lamps, none of which (to my knowledge)
> >>>>> is a simple LED.
> >>>> Many are.  As a matter of fact, I just installed a 12V wifi dimmer on my 12V LED strips lining the stair step in my theater.  I already have wifi control of the ceiling lights.  I just need them to come up slowly when turned on.  A VCO feeding a Triac / Diac pair should work, but I am unsure of details.
> >>>>
> >>>>> You could, however, operate a servo motor to lower a shade over a panel, or
> >>>>> rotate a polarizer, i.e. ignore the electronic range of such devices by... ignoring the electronic parts.
> >>>> No, no, no.  That is going off the rails.  All I need is a circuit with a slowly charging capacitor that changes the duty cycle of a Triac.
> >>>
> >>> Good luck with that.  I believe I would use an 8 pin MCU which is aware of the line voltage as well as the phase.  A problem with many dimmers is the poor response to line voltage changes, but then you won't be using it in a dimmed mode.  The dimming will be purely transient coming up to full brightness in a few seconds.
> >>>
> >>
> >> OP said he wants a circuit considerably smaller than a matchbox.
> >>
> >> I think the clearances required for 110VAC operation and the voltage
> >> ratings of the components you'll need to build a trailing-edge dimmer,
> >> say, are going to make that a problem if it all has to fit on a single
> >> board.
> >>
> >> Why the circuit MUST fit inside the bell-housing of a ceiling fan is
> >> unclear if this is a one-off personal application, sounds more like
> >> someone trying to integrate something for sale.
> >>
> >> Would recommend hiring an engineer in that case.
> > 
> > A 120 VAC circuit does not require any special clearances.  That would be for isolating high voltage and low voltage circuits.  This entire design can be treated as a high voltage circuit.
> 
> Enforcing some minimum distances between hot and neutral traces and any 
> exposed contacts with hot and neutral on them seems like a good 
> idea...resistors that are going to see the full rectified line voltage 
> across them at some point should be rated for 350 volts
> 
> > It has to go in the housing of the fan so it isn't stuck someplace even more crowded like the wall switch box.  That said, if a commercial product would do the job, but not fit in a match box (as if that were remotely likely) it would be very reasonable to add a box next to the fan mounting box which could then house a commercial circuit more easily.
> > 
> > But it does seem reasonable to simply add a wall dimmer switch in place of the toggle switch.  But maybe the lights are being brought up automatically by the "theater" system rather than manually switched on.  The automatic effect would be nice though.
> > 
> 
> It's a weird requirement for a one-off

What's weird about it???  I can see someone wanting to not blow out their theater experience by bringing up the lights abruptly.  I get that.  

There is a lot of home automation stuff on aliexpress, but you can never tell just what it really does.  They always push the Wow! factor rather than explaining it in any detail.  

The ads are SO into color!  Doesn't matter what it does, but it has to have color!!! 

-- 

  Rick C.

  -+ Get 1,000 miles of free Supercharging
  -+ Tesla referral code - https://ts.la/richard11209

On Thursday, 24 September 2020 14:54:25 UTC+1, Ricketty C  wrote:
> On Wednesday, September 23, 2020 at 5:39:52 AM UTC-4, Miguel Giménez wrote:
> > El 23/09/2020 a las 6:08, rhor...@gmail.com escribió:
> > > I need a simple circuit design for a slow fade-in AC dimmer.  In a dark theater, suddenly turning on the lights is a somewhat unpleasant experience.  I want a simple circuit compatible with 110 volt dimmable LED lights that will slowly ramp the light output over a period of about 5 seconds or so.  I have found a number of simple designs that would work for 12VDC LEDs, but none for 110VAC dimmable LED lights.
> > > 
> > 
> > We did that many years ago with a small microcontroller and a triac, it 
> > worked very well. The application was sunrise/sunset simulation in a 
> > city small-scale model.
> 
> Bet you weren't using LED lights.  LEDs often flicker a bit when used on triac type dimmers.  I've read some articles about why this happens, but don't recall the reasons.  I think it comes down to the fact that LED supplies don't naturally respond to changes in the AC duty cycle.  So they have to measure the phase angle of the triac turn on and adjust the dimming from that.  Since the full AC cycle is not presented to the supply the duty cycle is horrible.  
> 
> For all practical purposes triac type dimming is deprecated for use with LEDs.  Direct control via a low voltage or resistance is the recommended method.  But then this is an extra wire and a low voltage extra wire which must be run separately... in other words, a PITA.  

Series capacitor makes a lot more sense than a resistance. No extra wire needed.


NT

On Thursday, 24 September 2020 19:07:19 UTC+1, Ricketty C  wrote:
> On Thursday, September 24, 2020 at 12:02:33 PM UTC-4, bitrex wrote:

> > It's a weird requirement for a one-off
> 
> What's weird about it???  I can see someone wanting to not blow out their theater experience by bringing up the lights abruptly.  I get that.  
> 
> There is a lot of home automation stuff on aliexpress, but you can never tell just what it really does.  They always push the Wow! factor rather than explaining it in any detail.  
> 
> The ads are SO into color!  Doesn't matter what it does, but it has to have color!!! 

I forget the original requirement details. An NTC thermistor could fade up some LEDs extremely simply.


NT

On Thursday, September 24, 2020 at 4:33:20 PM UTC-4, Tabby wrote:
> On Thursday, 24 September 2020 14:54:25 UTC+1, Ricketty C  wrote:
> > On Wednesday, September 23, 2020 at 5:39:52 AM UTC-4, Miguel Giménez wrote:
> > > El 23/09/2020 a las 6:08, rhor...@gmail.com escribió:
> > > > I need a simple circuit design for a slow fade-in AC dimmer.  In a dark theater, suddenly turning on the lights is a somewhat unpleasant experience.  I want a simple circuit compatible with 110 volt dimmable LED lights that will slowly ramp the light output over a period of about 5 seconds or so.  I have found a number of simple designs that would work for 12VDC LEDs, but none for 110VAC dimmable LED lights.
> > > > 
> > > 
> > > We did that many years ago with a small microcontroller and a triac, it 
> > > worked very well. The application was sunrise/sunset simulation in a 
> > > city small-scale model.
> > 
> > Bet you weren't using LED lights.  LEDs often flicker a bit when used on triac type dimmers.  I've read some articles about why this happens, but don't recall the reasons.  I think it comes down to the fact that LED supplies don't naturally respond to changes in the AC duty cycle.  So they have to measure the phase angle of the triac turn on and adjust the dimming from that.  Since the full AC cycle is not presented to the supply the duty cycle is horrible.  
> > 
> > For all practical purposes triac type dimming is deprecated for use with LEDs.  Direct control via a low voltage or resistance is the recommended method.  But then this is an extra wire and a low voltage extra wire which must be run separately... in other words, a PITA.  
> 
> Series capacitor makes a lot more sense than a resistance. No extra wire needed.
> 
> 
> NT

Care to explain that in the context of my post?  I was talking about using commercially available dimmer circuits.  How are you talking of using a capacitor?  You mean to dim it only on application of power?  Yeah, I suppose that could work, but it requires building a circuit which is to the many issues of building a hobby circuit and adding it to a high voltage line. 

-- 

  Rick C.

  +- Get 1,000 miles of free Supercharging
  +- Tesla referral code - https://ts.la/richard11209

On Wednesday, September 23, 2020 at 9:53:12 AM UTC-5, Bill Sloman wrote:

> It's rather unrealistic ambition. He wants to control ten watts or more at 110V AC - about 100mA - and wants the whole thing in a package smaller than a matchbox, and simple with it. You can get quite a lot of surface mount components into that sort of volume, but it would need some reactive components, and ones that can cope with that kind of power tend to be a bit on the bulky side. 
> 
> -- 
> Bill Sloman, Sydney
So I suppose I am dreaming when I look at this dimmer sitting in my hand that is smaller than a pack of cards and can handle 600 watts?  Or the one below which handles 1000 watts AND includes WiFi?

https://www.amazon.com/DS-Wang-Module-90-250V-Automation-Intelligent/dp/B08HV6WXR6/ref=sr_1_45?crid=JOTC5FGUZFGB&dchild=1&keywords=wifi+fan+dimmer&qid=1601014148&sprefix=wifi+fan+dimmer%2Caps%2C182&sr=8-45