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Dungeon Dave
Hi, all. Relative newb here - relative in the sense that I used to dabble
in some electronics as a youngster and did some electronics theory in A-
level physics but that don't make me an expert as such.
Okay, so onto my problem. I bought a set of these the other day:
http://www.wickes.co.uk/Kitchen-Lighting/Accent-Ten-LED-Indoor-Light-
Kit/invt/190803
(actually, that doesn't look like the right package, but it'll do for the
purpose of this query)
- they're a string of white "nail" LEDs that are intended to mount in
thin plinths, powered by a plug-in transformer that delivers 12V to a
matchbox-sized distribution point. Since the DB just consists of 13
powered sockets in parallel connection, I'm guessing each LED has a
resistor in series to provide the correct voltage across the LED itself
(they may be bright, but I ain't heard of any LED that can take the ommpf
that 12V will pack and survive for too long!)
During the day, these lamps are bright enough, but I want to subdue them
for evening and night usage (I'm planning on leaving them on as
nightlights on the stairs, etc), so thought of just using a 12V dimmer of
some kind. Bill Bowden's site came up in a few google searches, and was
thinking of employing something like:
http://ourworld.compuserve.com/homepages/Bill_Bowden/page6.htm#dimmer.gif
(the site directed me to this forum)
However, it had me thinking: firstly, I have a transformer to drop
240AC->12DC, then another circuit on to lower the 12V... would I benefit
from combining the two into one? Build something that delivers a
rectified 2-12V output (looks like 5W max, BTW)? If so, are there
diagrams/kits (Vellmen, RS Electronics etc) readily available?
Secondly, I'd like to combine this with a timer circuit in some way, so
that it'd fire up at 100% brightness at one set time, dim to 20% (or
whatever preset I use) at a second time, then turn off completely at a
third time. I was toying with the idea of linking in a serial feed from a
USB controller then firing control information from my server (Linux,
running 24x7) so I could easily schedule something that determines what
brightness at what times of day I require, letting that ramp up/down the
lighting as I see fit. I've seen various projects online that cover this
info, but before dipping my toe in there, are there any more readily-
available circuits that can do this kind of timing-based control? Could I
hack away at a central heating controller? I'd prefer to have the self-
contained wall-mounted jobby if possible.
Okay... I know expecting someone to design something that exactly fits my
needs is asking a lot, given I've just strolled in here. However, I'm
guessing that if I'm going ot be reinventing the wheel through my
ignorance, I'm hoping someone can at least put me on the right road.
Thanks in advance, people!
in some electronics as a youngster and did some electronics theory in A-
level physics but that don't make me an expert as such.
Okay, so onto my problem. I bought a set of these the other day:
http://www.wickes.co.uk/Kitchen-Lighting/Accent-Ten-LED-Indoor-Light-
Kit/invt/190803
(actually, that doesn't look like the right package, but it'll do for the
purpose of this query)
- they're a string of white "nail" LEDs that are intended to mount in
thin plinths, powered by a plug-in transformer that delivers 12V to a
matchbox-sized distribution point. Since the DB just consists of 13
powered sockets in parallel connection, I'm guessing each LED has a
resistor in series to provide the correct voltage across the LED itself
(they may be bright, but I ain't heard of any LED that can take the ommpf
that 12V will pack and survive for too long!)
During the day, these lamps are bright enough, but I want to subdue them
for evening and night usage (I'm planning on leaving them on as
nightlights on the stairs, etc), so thought of just using a 12V dimmer of
some kind. Bill Bowden's site came up in a few google searches, and was
thinking of employing something like:
http://ourworld.compuserve.com/homepages/Bill_Bowden/page6.htm#dimmer.gif
(the site directed me to this forum)
However, it had me thinking: firstly, I have a transformer to drop
240AC->12DC, then another circuit on to lower the 12V... would I benefit
from combining the two into one? Build something that delivers a
rectified 2-12V output (looks like 5W max, BTW)? If so, are there
diagrams/kits (Vellmen, RS Electronics etc) readily available?
Secondly, I'd like to combine this with a timer circuit in some way, so
that it'd fire up at 100% brightness at one set time, dim to 20% (or
whatever preset I use) at a second time, then turn off completely at a
third time. I was toying with the idea of linking in a serial feed from a
USB controller then firing control information from my server (Linux,
running 24x7) so I could easily schedule something that determines what
brightness at what times of day I require, letting that ramp up/down the
lighting as I see fit. I've seen various projects online that cover this
info, but before dipping my toe in there, are there any more readily-
available circuits that can do this kind of timing-based control? Could I
hack away at a central heating controller? I'd prefer to have the self-
contained wall-mounted jobby if possible.
Okay... I know expecting someone to design something that exactly fits my
needs is asking a lot, given I've just strolled in here. However, I'm
guessing that if I'm going ot be reinventing the wheel through my
ignorance, I'm hoping someone can at least put me on the right road.
Thanks in advance, people!