Re: Making an X-10 lamp module immune to dimming

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

Dan, Robert Green and BruceR wrote:

> | > The instructions for the mod you seek can be found here:
> | > http://www.idobartana.com/hakb/
> | > Scroll down on the left to "Lamp Modules" and the sub heading "Making
a
> | > Silent Appliance Module" and start warming up your soldering iron!
> | >
> | > Ido's site is THE repository for X10 mods!
> |
> | Thanks!  I saw that and it's close but no ceegar.  One of the reasons to
do
> | this is so that lamps CAN respond to all lights on and off.
>
> The described modification does not affect the module's response to all
> lights on.  If you actually have lamp modules that respond to all lights
> off (none of mine do) it won't affect that either.

You're correct.  At first glance I thought he was talking about putting a
solid state relay inside an appliance module to eliminate the clack.  After
your comment, I went and tested the modules I have and while the wall
switches respond to All Lights ON/OFF, the lamp modules don't.  They only
respond to All Lights ON.  Bummer.  Well, that makes the project somewhat
less attractive.  At least the All Lights ON command is more useful to me
than All Lights Off would be.  How is that the X-10 security system flashes
the house lights?  Do lights on lamp modules turn on but not off?  My memory
seems to be that all lights turned on and off, but I could easily be
mistaken.  I think it's Mad Cow disease setting in.

> | I suppose in
> | the spirit of "Thomas Edison" whose strategy was often "try anything you
can
> | think of" I'll try cutting the control lines from the PIC to the triac
to
> | see what happens.
>
> Nothing useful will happen...

Well, such is the way of the "grunt and crank" method.  I would have at
least re-discovered the local sense mod for lamp modules.  My whole premise
was based on a misunderstanding of how triacs work.  I thought they were
merely high speed electronic relays.

> | It just seemed to me that
> | the bright and dim control circuit paths might be separate enough from
the
> | on off circuitry that one could be neutered without affecting the other.
>
> There is but one path.

It's become apparent that the triac can only do its magic when synched to
the zero crossing.  That became clear as I read through the modification
details.  Being a non-electrotechie, I assumed that a triac just passed
current until the trigger voltage was no longer applied, like a solid state
relay.  I also thought its other "claim to fame" was how incredibly quickly
it could switch and that tiny triggering currents could control much large
currents.  I just had hoped like the local sense problem, a simple snip
would do it.  Now it seems like the simplest mod is to extract the ZC data,
optically isolate it and then use it to inject the synchronizing signal into
the triac, assumable for it be able to reverse its polarity and pass current
flowing in the opposite direction for each half cycle of the AC line.

I've just disassembled a lamp module and it looks as though it's not as
crowded as I recall.  I have enough of these to practice on so that when the
weather turns hot, I might just attempt to undertake the modification.  I'd
still rather just clip a resistor lead to fix them but the discussion has at
least educated me as to why that's likely to have no effect.

Perhaps you could be kind enough to explain what would happen if the line to
the triac gate was high all the time.  Would it conduct only on the first
half cycle, or not at all or would the magic smoke escape?  (-:

--
Bobby G.