ac light dimmer 2.0, now with x10
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hi, last week I asked about making a dimmer with a stamp, and some ppl
on the list suggested I try an x10 device, which I did. Fun and easy.
However, what I really want to do is have a light slowly fade on. Using
the supported x10 commands listed in the bs2 docs, I was able to fade a
light on using the bright command, but only if the light had been dimmed
out first. Any advice?
thanks,
Mark
on the list suggested I try an x10 device, which I did. Fun and easy.
However, what I really want to do is have a light slowly fade on. Using
the supported x10 commands listed in the bs2 docs, I was able to fade a
light on using the bright command, but only if the light had been dimmed
out first. Any advice?
thanks,
Mark
Comments
> hi, last week I asked about making a dimmer with a stamp, and some
ppl
> on the list suggested I try an x10 device, which I did. Fun and
easy.
> However, what I really want to do is have a light slowly fade on.
Using
> the supported x10 commands listed in the bs2 docs, I was able to
fade a
> light on using the bright command, but only if the light had been
dimmed
> out first. Any advice?
>
> thanks,
>
> Mark
Mark, when you are working with the x10, and you are doing dimming,
you have to dim it to dark to "turn off" and brighten to where you
want it to "turn on". The x10 goes to full on when you turn it off
completely and then give the on command. I had that same prolem
using computer control.
Regards
Chet
it's not possible to have a circuit that does the following >
off > slowly brighten from off to on > off > slowly brighten from off
to on> repeat
>--- In basicstamps@yahoogroups.com, mark allen <m@m...> wrote:
>
>
>>hi, last week I asked about making a dimmer with a stamp, and some ppl
>>
>>
>>on the list suggested I try an x10 device, which I did. Fun and easy.
>>
>>
>>However, what I really want to do is have a light slowly fade on. Using
>>
>>
>>the supported x10 commands listed in the bs2 docs, I was able to fade a
>>
>>
>>light on using the bright command, but only if the light had been dimmed
>>
>>
>>out first. Any advice?
>>
>>thanks,
>>
>>Mark
>>
>>
>
>Mark, when you are working with the x10, and you are doing dimming,
>you have to dim it to dark to "turn off" and brighten to where you
>want it to "turn on". The x10 goes to full on when you turn it off
>completely and then give the on command. I had that same prolem
>using computer control.
>
>Regards
>
>Chet
>
>
>
>To UNSUBSCRIBE, just send mail to:
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>
>
>
>
>
>
>
>
'dim' to 0% on. If you actually use the
'off' command, the next 'on' OR any 'DIM'
command will turn the light on full-bright.
So, just never turn the light "off", instead
dim it to zero, then dim it up from zero
to get more light. This works fine.
--- In basicstamps@yahoogroups.com, mark allen <m@m...> wrote:
> Hi Chet, I found the same thing you are describing. Are you saying
that
> it's not possible to have a circuit that does the following >
>
> off > slowly brighten from off to on > off > slowly brighten from
off
> to on> repeat
>
> >--- In basicstamps@yahoogroups.com, mark allen <m@m...> wrote:
> >
> >
> >>hi, last week I asked about making a dimmer with a stamp, and
some ppl
> >>
> >>
> >>on the list suggested I try an x10 device, which I did. Fun and
easy.
> >>
> >>
> >>However, what I really want to do is have a light slowly fade on.
Using
> >>
> >>
> >>the supported x10 commands listed in the bs2 docs, I was able to
fade a
> >>
> >>
> >>light on using the bright command, but only if the light had been
dimmed
> >>
> >>
> >>out first. Any advice?
> >>
> >>thanks,
> >>
> >>Mark
> >>
> >>
> >
> >Mark, when you are working with the x10, and you are doing
dimming,
> >you have to dim it to dark to "turn off" and brighten to where you
> >want it to "turn on". The x10 goes to full on when you turn it
off
> >completely and then give the on command. I had that same prolem
> >using computer control.
> >
> >Regards
> >
> >Chet
> >
> >
> >
> >To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> >from the same email address that you subscribed. Text in the
Subject and Body of the message will be ignored.
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
wrote:
> With X10, you can do this, but only if you
> 'dim' to 0% on. If you actually use the
> 'off' command, the next 'on' OR any 'DIM'
> command will turn the light on full-bright.
>
> So, just never turn the light "off", instead
> dim it to zero, then dim it up from zero
> to get more light. This works fine.
This is typical of lights and motors. without some pretty good
circuits, you need to get the light to turn ON with a signifigant
amount of power. The filiment will act like a resistor and begin to
heat, then illuminate.
If you used a DC voltage to the lamp, you would lose some of the
brightness, but gain a lot of control.
for your Triac, look into a triac driver. I have been reading about
them and it seems you can get a triac driver that is an
optoisolator. it handles the zero corssing by activating the triac n
the first or second quadrante and therefor it only tries to control
the triac in the positive section of the sinewave.
Dave
"dim" anything. They're only useful for turning on big loads like contactor
coils. Their reason for existing is that they'll only ever start conducting
during the off-time of the sine wave, they won't cause any RF hash from the
big current that is drawn if a triac turns on while the AC is close to 170
volts... (yes, 120 RMS is close to 170 volts peak or 340 volts P to P). All
Triacs (and SCR's) wait for the voltage to return to near zero before they
unlatch, as it were. So they're all zero crossover on release.
Light dimmers work by turning "on" while the 120 Volt AC voltage is in the
middle of the cycle somewhere. In fact at 50% dimming, the triac is turning
on exactly at the peak voltage of the sine wave. That's why you can hear
light bulb filaments "sing" while dimming. It's the quick rise time of the
Triac that can make the filaments shake. High quality dimmers use a big
series inductor feeding the light bulbs which dramatically slows down that
rise time (flywheel effect) and limits the RF hash generated.
You can, if fact, rectify the 120 Volt RMS line voltage to about 170 Volts
DC, and then chop it rapidly with a big Mosfet using PWM without any of
the line-sync issues of Triac control. Of course, a 120 Volt light bulb is
at 100% power with 120 Volts, either RMS or DC, so you'll never be able to
apply 100% duty cycle 170 volt DC to one, or bad things will happen. Think
bright lights and a really quick burn out. (been there, done that).
I learned all this the hard way some 25 years ago when I built really big
light-dimmers for my rock band. Our main lighting rig had fifty 1KW PAR
lights with separate dimmers for each lamp. It really cooked. The real fun
was the strobe I built from a surplus airport landing strobe rated at 2,000
watt-seconds. We used a microwave transformer to power it up and an ignition
coil from a car to trigger it. When it fired it would completely overwhelm
the 50,000 watts of lighting we already had on stage, and we had to be very
careful not to look directly at the bulb. I did that once and was seeing big
purple flashes for the next few hours.
But I digress.....
Mike Sokol
mike@f...
www.fitsandstarts.com
" One should not increase, beyond what is necessary,
the number of entities required to explain anything"...
-William of Occam-
Original Message
From: "Dave Mucha" <davemucha@j...>
To: <basicstamps@yahoogroups.com>
Sent: Thursday, June 24, 2004 6:25 PM
Subject: [noparse][[/noparse]basicstamps] Re: ac light dimmer 2.0, now with x10
> --- In basicstamps@yahoogroups.com, "Allan Lane" <allan.lane@h...>
> wrote:
> > With X10, you can do this, but only if you
> > 'dim' to 0% on. If you actually use the
> > 'off' command, the next 'on' OR any 'DIM'
> > command will turn the light on full-bright.
> >
> > So, just never turn the light "off", instead
> > dim it to zero, then dim it up from zero
> > to get more light. This works fine.
>
>
> This is typical of lights and motors. without some pretty good
> circuits, you need to get the light to turn ON with a signifigant
> amount of power. The filiment will act like a resistor and begin to
> heat, then illuminate.
>
> If you used a DC voltage to the lamp, you would lose some of the
> brightness, but gain a lot of control.
>
> for your Triac, look into a triac driver. I have been reading about
> them and it seems you can get a triac driver that is an
> optoisolator. it handles the zero corssing by activating the triac n
> the first or second quadrante and therefor it only tries to control
> the triac in the positive section of the sinewave.
>
> Dave
>
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
> Just to expand a bit on zero-crossover triacs, they'll NEVER be
able to
> "dim" anything. They're only useful for turning on big loads like
contactor
> coils. Their reason for existing is that they'll only ever start
conducting
> during the off-time of the sine wave, they won't cause any RF hash
from the
> big current that is drawn if a triac turns on while the AC is close
to 170
> volts... (yes, 120 RMS is close to 170 volts peak or 340 volts P to
P). All
Interesting point here.
AC voltage times 1.414 would offer the peak voltage so if you are
thinking 120VAC RMS, it is really 170 peak or 340 P to P. and if
your mains fluxuate, considder 130VAC within utility compnay limits.
so 185V peak is not out of the question.
Also, considder that rectified AC with a filter can offer these
voltages in DC so the simple "convert to DC and dim" approach is not
totally simple.
A voltage monitoring/clipping circuit would be in order.
Dave
if you wish). The trick is not to switch the unit off. The "off"
is actualy fully dimmed.
Have ben using that for year now.
Good luck
Chet
--- In basicstamps@yahoogroups.com, mark allen <m@m...> wrote:
> Hi Chet, I found the same thing you are describing. Are you saying
that
> it's not possible to have a circuit that does the following >
>
> off > slowly brighten from off to on > off > slowly brighten from
off
> to on> repeat
>
> >--- In basicstamps@yahoogroups.com, mark allen <m@m...> wrote:
> >
> >
> >>hi, last week I asked about making a dimmer with a stamp, and
some ppl
> >>
> >>
> >>on the list suggested I try an x10 device, which I did. Fun and
easy.
> >>
> >>
> >>However, what I really want to do is have a light slowly fade
on. Using
> >>
> >>
> >>the supported x10 commands listed in the bs2 docs, I was able to
fade a
> >>
> >>
> >>light on using the bright command, but only if the light had
been dimmed
> >>
> >>
> >>out first. Any advice?
> >>
> >>thanks,
> >>
> >>Mark
> >>
> >>
> >
> >Mark, when you are working with the x10, and you are doing
dimming,
> >you have to dim it to dark to "turn off" and brighten to where
you
> >want it to "turn on". The x10 goes to full on when you turn it
off
> >completely and then give the on command. I had that same prolem
> >using computer control.
> >
> >Regards
> >
> >Chet
> >
> >
> >
> >To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> >from the same email address that you subscribed. Text in the
Subject and Body of the message will be ignored.
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >