Re: Re: LD11 - Can it be altered to operate using 12v dc or 24v dc

[ian.bird@xxxxxxxxxxxxxxxxxxxxxxx]

As I understand it the electronics use parasitic power for the signal
reading stuff etc. but essentially everything works at mains voltages.
Using a relay you are simply emulating the mains signals from 'proper'
wiring. A dim 'signal' is simply mains voltage applied to a contact for an
extended period of time (seconds or so). By keeping the relay energised
this is exactly what you will be doing.

These are the PCB prices from Olimex
PCB PROTO PANEL SSS - $26,00 USD
SINGLE SIDE EURO FORMAT PCB 160 mm x 100 mm (6.3" x 3.9")

PCB PROTO PANEL SSQ - $104,00 USD
SINGLE SIDE PCB PANEL 320 mm x 200 mm (12.6" x 7.8")

You would choose the correct one to get the number of smaller boards you
need. Neither is expensive I think you will agree. They will even panelise
(lots of small boards on one larger one) for free.

So, if you got 6 boards from the smaller size then each PCB will cost you
about 5 dollars or 3 quid each. They only do these sizes so you won't be
able to get one board for 3 quid, it must be 6 at 3 quid each. Add three
quid or so for components and a plastic box and the overall cost per box is
very reasonable. The end result is safe and repairable in the event of a
relay failure or something.

The opto is to keep from frying the cat5 yes, not to mention the person
pushing the switch who may not forgive you!!

And yes, the LD11 units are extra. just think of the satisfaction and
possible further market for these. I am sure you would not be the first to
want to do this or something similar.

Ian





"big_red_748"
<john.macnamara@globalcr        To:       ukha_d@xxxxxxx
ossing.com>                     cc:       (bcc: Ian Bird/CV/Novartis)
Subject:  [ukha_d] Re: LD11 - Can it be altered to operate using 12v dc or
24v dc
09/03/2005 12:39
Please respond to ukha_d










Thanks Ian, will your solution pass the signal to dim the lights?

I think I understand what you are trying to say re the opto isolater.
This is to stop mains voltage frying the CAT5E and light switch.  Is
that correct?

On top of all that equipment you listed, I would also have to buy the
LD11's.

I thought, if the LD11 internally converted the 240v ac input to 12
or 24v dc then it would be possible to bypass the 240v ac input and
connect directly the 12 or 24v dc with the CAT5E!

Cheers,


John



--- In ukha_d@xxxxxxx, ian.bird@c... wrote:
>
> I hear what you say (practising my corporate speak ;-)) but tbh the
price
> of the relays will be small. I don't have my price lists here but
you
> should be able to get the relays for a quid or so each.
>
> The next challenge is to mount them safely. As it happens my central
> heating switch thingy does just what you want. I take a 12 volt
signal
> which switches a relay which in turn carries mains voltages. Whilst
I would
> not recommend you to use the exact design the addition of an opto
isolator
> (no mains down the Cat5 cable) would not be a big deal. You can
even get
> professional printed circuit boards made for around 30 quid for 4
> (depending on size you may get more).
>
> So, relay and socket, opto isolator and socket, some connectors for
the
> various wires and a box to put it/them in. You should be able to
see that
> for a reasonable cost. Taking a worst case of around a tenner each
then 10
> circuits would only be a hundred quid + some time and effort.
>
> If you are interested then I would be happy to help with the PCB as
not
> everyone has the software (or inclination) for that. Having said
that
> www.olimex.com/pcb will accept files direct from Eagle
> http://www.cadsoft.de/ who do a
shareware version of their tool.
Just the
> time to learn it ;-(
>
> This would be a nice safe integrated solution where any failed
components
> could be replaced very easily.
>