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Re: TRIAC dimmer control spreadsheet; was Re: Controlling Holiday Lights
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> But in the case of TRIAC dimmer control
> (see thread subject) a single byte holds
> all the information needed to produce
> 2^8 =3D 256 levels *IF* one also knows when
> the zero crossing occurs as is conventional...
Yep. Since we don't even perceive 256 levels of dimming with the eye, =
this is than sufficient.
> But the single byte in the conventional
> approach is all the information that needs to
> be transmitted to the dimmer, or held in a
> register of a microcontroller or the latched
> input of a digital-to-analog (DA) converter.=20
This makes the whole process elegantly simple using existing technology. =
While other approachs may be able to yield finer control, it may not =
make a difference in real world applications. I'm all for creativity, =
even for creativity's own sake, so I hope Sylvan has better results than =
what I expect. More power to him (yes, pun intended) if he can.
=20
> Applying 'perceptual coding" to that single
> 8-bit byte, we could usefully 'compress' it
> to a 4-bit nibble to produce 16 levels if that
> is all that is needed.
>=20
> So, for example the table at:
> http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf=20
>=20
> can be used to select values for a new, equal
> intensity, 16-step dimmer curve with Full ON,
> Full OFF and 14 intermediate steps each
> causing about 6% reduction in light intensity.
> This would be 'perceptually' plenty good
> enough in nearly all practical home automation
> scenarios.
I'd rather have a tad finer control than intermediate 14 steps between =
on and off for setting up home theater and "mood" scenes involving =
multiple fixtures. Then again, I'm kind of picky. What I *really* =
would like to have is precise fade rate controls for home lighting. =
Working with PC-based lighting boards even a little spoils you. :^)
Note to Sylvan: This discussion has gotten a little edgy at times. We =
disagree on a few of your ideas but I'm interested to see what you =
develop. I hope that none of my comments on this matter have sounded =
disrespectful to you because that has not been my intention. If it =
seems so, I apologize.
--=20
Regards,
Robert L Bass
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D>
Bass Home Electronics
941-866-1100
4883 Fallcrest Circle
Sarasota =B7 Florida =B7 34233
http://www.bassburglaralarms.com
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D>
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<DIV><FONT size=3D2>> But in the case of TRIAC dimmer =
control</FONT></DIV>
<DIV><FONT size=3D2>> (see thread subject) a single byte=20
holds</FONT></DIV>
<DIV><FONT size=3D2>> all the information needed to=20
produce</FONT></DIV>
<DIV><FONT size=3D2>> 2^8 =3D 256 levels *IF* one also =
knows=20
when</FONT></DIV>
<DIV><FONT size=3D2>> the zero crossing occurs as is=20
conventional...</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Yep. Since we don't even perceive 256 levels =
of dimming=20
with the eye, this is than sufficient.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>> But the single byte in the =
conventional</FONT></DIV>
<DIV><FONT size=3D2>> approach is all the information that needs =
to</FONT></DIV>
<DIV><FONT size=3D2>> be transmitted to the dimmer, or held in=20
a</FONT></DIV>
<DIV><FONT size=3D2>> register of a microcontroller or the=20
latched</FONT></DIV>
<DIV><FONT size=3D2>> input of a digital-to-analog (DA)=20
converter. <BR></FONT></DIV>
<DIV><FONT size=3D2>This makes the whole process elegantly simple using =
existing=20
technology. While other approachs may be able to yield =
finer control,=20
it may not make a difference in real world applications. I'm all =
for=20
creativity, even for creativity's own sake, so I hope Sylvan has better =
results=20
than what I expect. More power to him (yes, pun intended) if he=20
can.</FONT></DIV>
<DIV><FONT size=3D2> <BR>> Applying 'perceptual coding" to that=20
single</FONT></DIV>
<DIV><FONT size=3D2>> 8-bit byte, we could usefully 'compress'=20
it</FONT></DIV>
<DIV><FONT size=3D2>> to a 4-bit nibble to produce 16 levels if=20
that</FONT></DIV>
<DIV><FONT size=3D2>> is all that is needed.</FONT></DIV>
<DIV><FONT size=3D2>> <BR>> So, for example the table at:<BR>> =
</FONT><A=20
href=3D"http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf";><FON=
T=20
size=3D2>http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf</FON=
T></A><FONT=20
size=3D2> <BR>> <BR>> can be used to select values for a new,=20
equal</FONT></DIV>
<DIV><FONT size=3D2>> intensity, 16-step dimmer curve with Full=20
ON,</FONT></DIV>
<DIV><FONT size=3D2>> Full OFF and 14 intermediate steps =
each</FONT></DIV>
<DIV><FONT size=3D2>> causing about 6% reduction in light=20
intensity.</FONT></DIV>
<DIV><FONT size=3D2>> This would be 'perceptually' plenty =
good</FONT></DIV>
<DIV><FONT size=3D2>> enough in nearly all practical home=20
automation</FONT></DIV>
<DIV><FONT size=3D2>> scenarios.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>I'd rather have a tad finer control than =
intermediate 14 steps=20
between on and off for setting up home theater and "mood" scenes =
involving=20
multiple fixtures. Then again, I'm kind of picky. What I =
*really*=20
would like to have is precise fade rate controls for home =
lighting. =20
Working with PC-based lighting boards even a little spoils you. =20
:^)</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Note to Sylvan: This discussion has gotten a =
little edgy=20
at times. We disagree on a few of your ideas but I'm interested to =
see=20
what you develop. I hope that none of my comments on this matter =
have=20
sounded disrespectful to you because that has not been my =
intention. If it=20
seems so, I apologize.</FONT></DIV>
<DIV><BR><FONT size=3D2>-- </FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Regards,<BR>Robert L Bass</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT =
size=3D2>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D><BR>Bass Home=20
Electronics<BR>941-866-1100<BR>4883 Fallcrest Circle<BR>Sarasota =B7 =
Florida =B7=20
34233<BR></FONT><A href=3D"http://www.bassburglaralarms.com";><FONT=20
size=3D2>http://www.bassburglaralarms.com</FONT></A><BR><FONT=20
size=3D2>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D></FONT></DIV></BODY></HTML>
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