The cupboard has two doors, which open independently. The plan is to fit two
push switches of the type sold for this purpose, one for each door. The
switches will control a light that will shine into the cupboard, which is
rather deep and gloomy. These switches are 'on' when the plunger is out, so
the light comes on when the door is open. I also intend to use a timer so
that if the door or doors are left open the light will eventually go out.
The timer will commence timing when the supply is applied (the door(s) are
opened) and if the door or doors are left open the light will eventually go
out. If the doors are closed during the timing period the light will go out
immediately. In order to initiate a timing period and turn the light on the
door must be closed, then the timing period starts when the door opens. I've
sorted the timer out. It's a multifunction one, and it does what I want. But
ideally I'd like the light to come on if either or both doors are opened,
and stay on for the full duration of the timing period even if one of the
two doors is shut. With one door it's simple. The one switch controls the
timer perfectly. But with two doors and two switches the best I've done is
to have the switches in series, so that both doors have to be open to
initiate the timing period. With the switches in parallel, if one door has
been left open the timing period will not commence when the other door is
opened. It is necesssary for both doors to be closed, then either to be
opened. If the switches are in series, for the timing period to start one or
both doors must be shut, then both must be open.

Suggestions anyone?

Bill

Bill Wright formulated the question :
Suggestions anyone?

I can only think of using two such timers in parallel each fed from a
door switch, or a pair of instantaneous switches - ones which makes
briefly as a door is opened, then relying entirely on the timer.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Mon, 7 Sep 2009 20:17:17 +0100, Bill Wright wrote:

I've sorted the timer out. It's a multifunction one, and it does what I
want.

Patently it doesn't or you wouldn't be asking the question... B-)

What does your multifunction timer switch need to trigger and
retrigger the timing period? I suspect it needs a rising edge,
generating that with just two SPST switches is going to be tricky.
Some devious arrangement of two DTDT switches *might* do it utilising
the break when a switch changes over to produce the rising edge. SPDT
switches won't work in the normal lighting two way switching
arrangement.

I suspect your easiest solution will be to find a timer module with
two trigger inputs. You may have to go as far as a small PLC.

--
Cheers
Dave.

Dave Liquorice has brought this to us :
You may have to go as far as a small PLC.

To turn a light on 8-o

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

In article ,
Bill Wright wrote:
The cupboard has two doors, which open independently. The plan is to fit
two push switches of the type sold for this purpose, one for each door.
The switches will control a light that will shine into the cupboard,
which is rather deep and gloomy. These switches are 'on' when the
plunger is out, so the light comes on when the door is open. I also
intend to use a timer so that if the door or doors are left open the
light will eventually go out. The timer will commence timing when the
supply is applied (the door(s) are opened) and if the door or doors are
left open the light will eventually go out. If the doors are closed
during the timing period the light will go out immediately. In order to
initiate a timing period and turn the light on the door must be closed,
then the timing period starts when the door opens. I've sorted the
timer out. It's a multifunction one, and it does what I want. But
ideally I'd like the light to come on if either or both doors are
opened, and stay on for the full duration of the timing period even if
one of the two doors is shut. With one door it's simple. The one switch
controls the timer perfectly. But with two doors and two switches the
best I've done is to have the switches in series, so that both doors
have to be open to initiate the timing period. With the switches in
parallel, if one door has been left open the timing period will not
commence when the other door is opened. It is necesssary for both doors
to be closed, then either to be opened. If the switches are in series,
for the timing period to start one or both doors must be shut, then
both must be open.

Suggestions anyone?

There's probably a way of doing it with logic - but since you're using a
timer to switch the load I'd fit two reed burglar alarm switches per side
- the type with changeover contacts. Some clever wiring of those should
give you the logic you need. They'll be more reliable in operation too
than those pukka door switches which are quite critical in how they're
installed.

--
He who laughs last, thinks slowest*

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Liquorice" wrote in message
ll.co.uk...
On Mon, 7 Sep 2009 20:17:17 +0100, Bill Wright wrote:

I've sorted the timer out. It's a multifunction one, and it does what I
want.

Patently it doesn't or you wouldn't be asking the question... B-)
Ha! Well, it worked fine til the person building the cupboard decided to fit
two doors instead of one big one!


What does your multifunction timer switch need to trigger and
retrigger the timing period?
In the mode that I'm using it needs power on. This starts the timing period.

I suspect it needs a rising edge,
generating that with just two SPST switches is going to be tricky.
Some devious arrangement of two DTDT switches *might* do it utilising
the break when a switch changes over to produce the rising edge. SPDT
switches won't work in the normal lighting two way switching
arrangement.
I see what you mean.


I suspect your easiest solution will be to find a timer module with
two trigger inputs. You may have to go as far as a small PLC.
I suppose I could use two timers, but it's a faff and an expense.

Bill

"Dave Plowman (News)" wrote in message
...
In article ,
There's probably a way of doing it with logic - but since you're using a
timer to switch the load I'd fit two reed burglar alarm switches per side
- the type with changeover contacts. Some clever wiring of those should
give you the logic you need. They'll be more reliable in operation too
than those pukka door switches which are quite critical in how they're
installed.

It's funny that, because I've done this job in motorhomes (a simple one
switch-one light arrangement with no timer) and I've had problems with reed
switches sticking (this was on 12V DC), so this time I decided to use
mechanical ones! I must say these mechanical switches don't seem very good.
The push force needed is quite high for one thing.

Re reed switches, I've used them for gate contacts and found that they fail.
This is with big butch ones. Someone advised a cap (can't remember the
value) across the switch and that helped a lot.

Bill

On Tue, 08 Sep 2009 03:28:41 +0100, John Rumm wrote:

A couple of relays should do it:

http://wiki.diyfaq.org.uk/images/6/6...esetswitch.gif

It's early so brain not fully up to working caffine levels but I
don't think that will reset the timer if one door is already open and
the other is opened.

You will need to shut both doors to get the light to come on again.

Ah it doesn't, unfortunately that breaks the spec...

Have you got the logic/wiring the right way round for "elapsed" and
RL2? Or is your design to keep the elasped high and the relay
energised to keep the lamp off with the doors shut. Wouldn't it be
better to have the RL2 energised only when the lamp is supposed to be
on?

We really need to know the make/model/version of Bill's timer before
thinking much harder about the logic/switching arrangements. Perhaps
it does have a "reset/retrigger" input perhaps it doesn't just being
a simple delayed off non-retriggerable device.

--
Cheers
Dave.

In article ,
Bill Wright wrote:
It's funny that, because I've done this job in motorhomes (a simple one
switch-one light arrangement with no timer) and I've had problems with
reed switches sticking (this was on 12V DC), so this time I decided to
use mechanical ones! I must say these mechanical switches don't seem
very good. The push force needed is quite high for one thing.

They also tend to push a near closed door open. Switching on the light.

Re reed switches, I've used them for gate contacts and found that they
fail. This is with big butch ones. Someone advised a cap (can't
remember the value) across the switch and that helped a lot.

I've got them on near every window and door here on my home installed
alarm and haven't had one failure. Decent reed switches have a very long
service life - assuming their rating isn't exceeded. If you're using an
electronic timer the trigger current should be tiny. I dunno how they cope
with vibration though - but this won't be a problem indoors.

If you're not familiar with alarm types there are two suitable - either
flush fitting or surface mount. Switch and magnet come in similar housings.

http://www.tlc-direct.co.uk/Main_Ind...ies/index.html

--
*There's two theories to arguing with a woman. Neither one works *

Dave Plowman London SW
To e-mail, change noise into sound.

"Bill Wright" wrote in message
...
The cupboard has two doors, which open independently. The plan is to fit
two push switches of the type sold for this purpose, one for each door.
The switches will control a light that will shine into the cupboard, which
is rather deep and gloomy. These switches are 'on' when the plunger is
out, so the light comes on when the door is open. I also intend to use a
timer so that if the door or doors are left open the light will eventually
go out. The timer will commence timing when the supply is applied (the
door(s) are opened) and if the door or doors are left open the light will
eventually go out. If the doors are closed during the timing period the
light will go out immediately. In order to initiate a timing period and
turn the light on the door must be closed, then the timing period starts
when the door opens. I've sorted the timer out. It's a multifunction one,
and it does what I want. But ideally I'd like the light to come on if
either or both doors are opened, and stay on for the full duration of the
timing period even if one of the two doors is shut. With one door it's
simple. The one switch controls the timer perfectly. But with two doors
and two switches the best I've done is to have the switches in series, so
that both doors have to be open to initiate the timing period. With the
switches in parallel, if one door has been left open the timing period
will not commence when the other door is opened. It is necesssary for both
doors to be closed, then either to be opened. If the switches are in
series, for the timing period to start one or both doors must be shut,
then both must be open.

Suggestions anyone?

Bill


Have the original switches paralleled, then install a second switch on each
door that is normally closed, but on opening the door, it is pressed and
released (Like a bell switch on a shop door, but normally closed), wire
these in series with the paralleled original switches.

Toby...

On 7 Sep, 20:17, "Bill Wright" wrote:
The cupboard has two doors, which open independently. The plan is to fit two
push switches of the type sold for this purpose, one for each door. The
switches will control a light that will shine into the cupboard, which is
rather deep and gloomy. These switches are 'on' when the plunger is out, so
the light comes on when the door is open. I also intend to use a timer so
that if the door or doors are left open the light will eventually go out.
The timer will commence timing when the supply is applied (the door(s) are
opened) and if the door or doors are left open the light will eventually go
out. If the doors are closed during the timing period the light will go out
immediately. In order to initiate a timing period and turn the light on the
door must be closed, then the timing period starts when the door opens. I've
sorted the timer out. It's a multifunction one, and it does what I want. But
ideally I'd like the light to come on if either or both doors are opened,
and stay on for the full duration of the timing period even if one of the
two doors is shut. With one door it's simple. The one switch controls the
timer perfectly. But with two doors and two switches the best I've done is
to have the switches in series, so that both doors have to be open to
initiate the timing period. With the switches in parallel, if one door has
been left open the timing period will not commence when the other door is
opened. It is necesssary for both doors to be closed, then either to be
opened. If the switches are in series, for the timing period to start one or
both doors must be shut, then both must be open.

Suggestions anyone?

Bill

I'd use a PIR sensor and a timer, or even a PIR sensor with a timer
built in.

T

On 8 Sep, 10:46, Recyclist wrote:
On 7 Sep, 20:17, "Bill Wright" wrote:





The cupboard has two doors, which open independently. The plan is to fit two
push switches of the type sold for this purpose, one for each door. The
switches will control a light that will shine into the cupboard, which is
rather deep and gloomy. These switches are 'on' when the plunger is out, so
the light comes on when the door is open. I also intend to use a timer so
that if the door or doors are left open the light will eventually go out.
The timer will commence timing when the supply is applied (the door(s) are
opened) and if the door or doors are left open the light will eventually go
out. If the doors are closed during the timing period the light will go out
immediately. In order to initiate a timing period and turn the light on the
door must be closed, then the timing period starts when the door opens. I've
sorted the timer out. It's a multifunction one, and it does what I want. But
ideally I'd like the light to come on if either or both doors are opened,
and stay on for the full duration of the timing period even if one of the
two doors is shut. With one door it's simple. The one switch controls the
timer perfectly. But with two doors and two switches the best I've done is
to have the switches in series, so that both doors have to be open to
initiate the timing period. With the switches in parallel, if one door has
been left open the timing period will not commence when the other door is
opened. It is necesssary for both doors to be closed, then either to be
opened. If the switches are in series, for the timing period to start one or
both doors must be shut, then both must be open.

Suggestions anyone?

Bill

I'd use a PIR sensor and a timer, or even a PIR sensor with a timer
built in.

T- Hide quoted text -

- Show quoted text -

Or a photo-sensor, if it doesn't matter that the cupboard light won't
come on if it is dark and there are no other lights on nearby (which
doesn't seem too unreasonable).

On 8 Sep, 12:56, Bolted wrote:
On 8 Sep, 10:46, Recyclist wrote:



On 7 Sep, 20:17, "Bill Wright" wrote:

The cupboard has two doors, which open independently. The plan is to fit two
push switches of the type sold for this purpose, one for each door. The
switches will control a light that will shine into the cupboard, which is
rather deep and gloomy. These switches are 'on' when the plunger is out, so
the light comes on when the door is open. I also intend to use a timer so
that if the door or doors are left open the light will eventually go out.
The timer will commence timing when the supply is applied (the door(s) are
opened) and if the door or doors are left open the light will eventually go
out. If the doors are closed during the timing period the light will go out
immediately. In order to initiate a timing period and turn the light on the
door must be closed, then the timing period starts when the door opens. I've
sorted the timer out. It's a multifunction one, and it does what I want. But
ideally I'd like the light to come on if either or both doors are opened,
and stay on for the full duration of the timing period even if one of the
two doors is shut. With one door it's simple. The one switch controls the
timer perfectly. But with two doors and two switches the best I've done is
to have the switches in series, so that both doors have to be open to
initiate the timing period. With the switches in parallel, if one door has
been left open the timing period will not commence when the other door is
opened. It is necesssary for both doors to be closed, then either to be
opened. If the switches are in series, for the timing period to start one or
both doors must be shut, then both must be open.

Suggestions anyone?

Bill

I'd use a PIR sensor and a timer, or even a PIR sensor with a timer
built in.

T- Hide quoted text -

- Show quoted text -

Or a photo-sensor, if it doesn't matter that the cupboard light won't
come on if it is dark and there are no other lights on nearby (which
doesn't seem too unreasonable).

A photo-sensor to switch a light on?

T

On Tue, 08 Sep 2009 09:37:12 +0100, Dave Plowman (News) wrote:

Decent reed switches have a very long service life - assuming their
rating isn't exceeded.

Aye, there is one in the anemomter that is currently whizzing round
in an F7 near gale outside, producing a pulse every rotation. That
reed switch has failed in the past but this one has been in service
for at least a couple of years.

So lets say 60 rpm average, we do get calm days and days like now. 1
pulse/sec or 63,072,000 operations over two years...

--
Cheers
Dave.

On 8 Sep, 13:00, Recyclist wrote:
On 8 Sep, 12:56, Bolted wrote:





On 8 Sep, 10:46, Recyclist wrote:

On 7 Sep, 20:17, "Bill Wright" wrote:

The cupboard has two doors, which open independently. The plan is to fit two
push switches of the type sold for this purpose, one for each door. The
switches will control a light that will shine into the cupboard, which is
rather deep and gloomy. These switches are 'on' when the plunger is out, so
the light comes on when the door is open. I also intend to use a timer so
that if the door or doors are left open the light will eventually go out.
The timer will commence timing when the supply is applied (the door(s) are
opened) and if the door or doors are left open the light will eventually go
out. If the doors are closed during the timing period the light will go out
immediately. In order to initiate a timing period and turn the light on the
door must be closed, then the timing period starts when the door opens. I've
sorted the timer out. It's a multifunction one, and it does what I want. But
ideally I'd like the light to come on if either or both doors are opened,
and stay on for the full duration of the timing period even if one of the
two doors is shut. With one door it's simple. The one switch controls the
timer perfectly. But with two doors and two switches the best I've done is
to have the switches in series, so that both doors have to be open to
initiate the timing period. With the switches in parallel, if one door has
been left open the timing period will not commence when the other door is
opened. It is necesssary for both doors to be closed, then either to be
opened. If the switches are in series, for the timing period to start one or
both doors must be shut, then both must be open.

Suggestions anyone?

Bill

I'd use a PIR sensor and a timer, or even a PIR sensor with a timer
built in.

T- Hide quoted text -

- Show quoted text -

Or a photo-sensor, if it doesn't matter that the cupboard light won't
come on if it is dark and there are no other lights on nearby (which
doesn't seem too unreasonable).

A photo-sensor to switch a light on?

Yes, it's a cupboard which is a bit gloomy with a door open and very
much more gloomy with the doors shut. As long as you have daylight
or other lights on nearby, with suitable tweaking of the sensitivity
there is no reason it won't work.

On 8 Sep, 21:42, Bolted wrote:
On 8 Sep, 13:00, Recyclist wrote:



On 8 Sep, 12:56, Bolted wrote:

On 8 Sep, 10:46, Recyclist wrote:

On 7 Sep, 20:17, "Bill Wright" wrote:

The cupboard has two doors, which open independently. The plan is to fit two
push switches of the type sold for this purpose, one for each door. The
switches will control a light that will shine into the cupboard, which is
rather deep and gloomy. These switches are 'on' when the plunger is out, so
the light comes on when the door is open. I also intend to use a timer so
that if the door or doors are left open the light will eventually go out.
The timer will commence timing when the supply is applied (the door(s) are
opened) and if the door or doors are left open the light will eventually go
out. If the doors are closed during the timing period the light will go out
immediately. In order to initiate a timing period and turn the light on the
door must be closed, then the timing period starts when the door opens. I've
sorted the timer out. It's a multifunction one, and it does what I want. But
ideally I'd like the light to come on if either or both doors are opened,
and stay on for the full duration of the timing period even if one of the
two doors is shut. With one door it's simple. The one switch controls the
timer perfectly. But with two doors and two switches the best I've done is
to have the switches in series, so that both doors have to be open to
initiate the timing period. With the switches in parallel, if one door has
been left open the timing period will not commence when the other door is
opened. It is necesssary for both doors to be closed, then either to be
opened. If the switches are in series, for the timing period to start one or
both doors must be shut, then both must be open.

Suggestions anyone?

Bill

I'd use a PIR sensor and a timer, or even a PIR sensor with a timer
built in.

T- Hide quoted text -

- Show quoted text -

Or a photo-sensor, if it doesn't matter that the cupboard light won't
come on if it is dark and there are no other lights on nearby (which
doesn't seem too unreasonable).

A photo-sensor to switch a light on?

Yes, it's a cupboard which is a bit gloomy with a door open and very
much more gloomy with the doors shut. * As long as you have daylight
or other lights on nearby, with suitable tweaking of the sensitivity
there is no reason it won't work.

So, how do you get the light to switch off?

T

Bill Wright wrote on 08/09/2009 :
Re reed switches, I've used them for gate contacts and found that they fail.
This is with big butch ones. Someone advised a cap (can't remember the value)
across the switch and that helped a lot.

They are not very good at handling inductive loads which would cause
the contacts to weld.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

John Rumm formulated the question :
Dave Liquorice wrote:
On Tue, 08 Sep 2009 09:37:12 +0100, Dave Plowman (News) wrote:

Decent reed switches have a very long service life - assuming their rating
isn't exceeded.

Aye, there is one in the anemomter that is currently whizzing round
in an F7 near gale outside, producing a pulse every rotation. That
reed switch has failed in the past but this one has been in service
for at least a couple of years.

So lets say 60 rpm average, we do get calm days and days like now. 1
pulse/sec or 63,072,000 operations over two years...

I have one which has been running for 15 months so far without failure.


Prolly better off with a hall effect switch rather than a reed with that many
cycles...

Problem is the unit is battery powered and at the top of a pole. Reed
switches need much less power.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On 8 Sep, 22:35, Owain wrote:
On 8 Sep, 21:58, Recyclist *wrote:

A photo-sensor to switch a light on?
Yes, it's a cupboard which is a bit gloomy with a door open and very
much more gloomy with the doors shut. * As long as you have daylight
or other lights on nearby, with suitable tweaking of the sensitivity
there is no reason it won't work.
So, how do you get the light to switch off?

You close the doors. The cupboard is in darkness. Note - the photocell
is inside the cupboard. The light is *outside* the cupboard shining in
(AIUI)

Owain

That, and it is on a timer.

In article ,
Harry Bloomfield wrote:
Bill Wright wrote on 08/09/2009 :
Re reed switches, I've used them for gate contacts and found that they
fail. This is with big butch ones. Someone advised a cap (can't
remember the value) across the switch and that helped a lot.

They are not very good at handling inductive loads which would cause
the contacts to weld.

But Bill says he's using a timer - and I assume an electronic one which
would not have an inductive input.

--
*I like cats, too. Let's exchange recipes.

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article ,
Harry Bloomfield wrote:
Bill Wright wrote on 08/09/2009 :
Re reed switches, I've used them for gate contacts and found that they
fail. This is with big butch ones. Someone advised a cap (can't
remember the value) across the switch and that helped a lot.

They are not very good at handling inductive loads which would cause
the contacts to weld.

But Bill says he's using a timer - and I assume an electronic one which
would not have an inductive input.

Yes, but this wasn't about the cupboards it was about the reed switches on
the gates.

Bill

On 8 Sep, 23:53, Bolted wrote:
On 8 Sep, 22:35, Owain wrote:

On 8 Sep, 21:58, Recyclist *wrote:

A photo-sensor to switch a light on?
Yes, it's a cupboard which is a bit gloomy with a door open and very
much more gloomy with the doors shut. * As long as you have daylight
or other lights on nearby, with suitable tweaking of the sensitivity
there is no reason it won't work.
So, how do you get the light to switch off?

You close the doors. The cupboard is in darkness. Note - the photocell
is inside the cupboard. The light is *outside* the cupboard shining in
(AIUI)

Owain

That, and it is on a timer.

I'd assumed that the light would be in the cupboard! If the light is
*outside* the cupboard, then I'm afraid I think the whole idea is over-
complex and a bit ridiculous. But if the OP does take your advice to
fit a photocell, then a timer is pointless and wasteful.

T

In article ,
Bill Wright wrote:

"Dave Plowman (News)" wrote in message
...
In article ,
Harry Bloomfield wrote:
Bill Wright wrote on 08/09/2009 :
Re reed switches, I've used them for gate contacts and found that
they fail. This is with big butch ones. Someone advised a cap
(can't remember the value) across the switch and that helped a lot.

They are not very good at handling inductive loads which would cause
the contacts to weld.

But Bill says he's using a timer - and I assume an electronic one which
would not have an inductive input.

Yes, but this wasn't about the cupboards it was about the reed switches
on the gates.

Ok. But was the one you had problems with used within its rating? Any
switch will fail if you exceed that. They're basically signal rather than
power switches.



--
*If God had wanted me to touch my toes, he would have put them on my knees

Dave Plowman London SW
To e-mail, change noise into sound.

On 9 Sep, 09:55, Recyclist wrote:
On 8 Sep, 23:53, Bolted wrote:





On 8 Sep, 22:35, Owain wrote:

On 8 Sep, 21:58, Recyclist *wrote:

A photo-sensor to switch a light on?
Yes, it's a cupboard which is a bit gloomy with a door open and very
much more gloomy with the doors shut. * As long as you have daylight
or other lights on nearby, with suitable tweaking of the sensitivity
there is no reason it won't work.
So, how do you get the light to switch off?

You close the doors. The cupboard is in darkness. Note - the photocell
is inside the cupboard. The light is *outside* the cupboard shining in
(AIUI)

Owain

That, and it is on a timer.

I'd assumed that the light would be in the cupboard!

The original post suggests the light will be outside, shining in. I
may have read too much into that, but I am in the middle of installing
something very similar with some directional ceiling spots which will
come on when cupboard doors underneath them are opened. (I've gone for
NO reed switches, in series, FWIW).

If the light is *outside* the cupboard, then I'm afraid I think the whole idea is over-
complex and a bit ridiculous.

What difference does it make where the luminaire is - as long as the
light gets into the cupboard.

But if the OP does take your advice to
fit a photocell, then a timer is pointless and wasteful.

Yes, if the light is outside, but not if the light is inside (because
your point would otherwise apply!)

On 07/09/2009 20:17, Bill Wright wrote:
The cupboard has two doors, which open independently. The plan is to fit two
push switches of the type sold for this purpose, one for each door. The
switches will control a light that will shine into the cupboard, which is
rather deep and gloomy. These switches are 'on' when the plunger is out, so
the light comes on when the door is open. I also intend to use a timer so
that if the door or doors are left open the light will eventually go out.
The timer will commence timing when the supply is applied (the door(s) are
opened) and if the door or doors are left open the light will eventually go
out. If the doors are closed during the timing period the light will go out
immediately. In order to initiate a timing period and turn the light on the
door must be closed, then the timing period starts when the door opens. I've
sorted the timer out. It's a multifunction one, and it does what I want. But
ideally I'd like the light to come on if either or both doors are opened,
and stay on for the full duration of the timing period even if one of the
two doors is shut. With one door it's simple. The one switch controls the
timer perfectly. But with two doors and two switches the best I've done is
to have the switches in series, so that both doors have to be open to
initiate the timing period. With the switches in parallel, if one door has
been left open the timing period will not commence when the other door is
opened. It is necesssary for both doors to be closed, then either to be
opened. If the switches are in series, for the timing period to start one or
both doors must be shut, then both must be open.

Suggestions anyone?

Bill


Fit a security type PIR in the cupboard and take the switched feed out
of it via the two door switches (wired in parallel) perhaps?

http://www.tlc-direct.co.uk/Main_Ind...ors/index.html

The PIR then implements the timing period for you...

Bill Wright wrote:

The cupboard has two doors, which open independently...
snip

Hi Bill,

I haven't got time to plough through this thread right now, but have you
resolved your light circuit problem?

It seems quite straightforward (your door switch contacts will have to be
wired in parallel).

A simple DE (Delay on Energisation) timer is all you seem to need. No need
for any relays.

What timer have you obtained (manufacturer and type/model number please).

What supply and voltage are you using (e.g. mains 230V, 50Hz).

I'll sketch you out a circuit over the next day or so and email it direct
(if you have registered a valid email address).
--
Razoo

In article ,
mlv wrote:
I haven't got time to plough through this thread right now, but have you
resolved your light circuit problem?

It seems quite straightforward (your door switch contacts will have to
be wired in parallel).

A simple DE (Delay on Energisation) timer is all you seem to need. No
need for any relays.

You need to read Bill's requirements more carefully...

--
*A conclusion is the place where you got tired of thinking *

Dave Plowman London SW
To e-mail, change noise into sound.

"mlv" wrote in message
...
Bill Wright wrote:

The cupboard has two doors, which open independently...
snip

Hi Bill,

I haven't got time to plough through this thread right now, but have you
resolved your light circuit problem?
No. The cabinet maker has agreed to make the panel at the top of the unit
removable, so I will be able to re-do the switches if neccessary, so I
thought I'd see whether the present disadvantages matter in practice.

It seems quite straightforward (your door switch contacts will have to be
wired in parallel).
If they are in parallel, to start the timing period the supply (or trigger;
it doesn't matter which) must be removed and then restored. So both doors
must be shut and then one or both opened. That's OK unless you've left a
door open and the timing period has ended when you want the light on. It
means that you have to shut the door then open it. Ideally I wanted the
light to come on if one door was opened, even if the other had been left
open previously.

A simple DE (Delay on Energisation) timer is all you seem to need. No
need for any relays.
Well, it's a multifuntion timer from RS, set to Delay on Energisation.

What supply and voltage are you using (e.g. mains 230V, 50Hz).
Mains.


I'll sketch you out a circuit over the next day or so and email it direct
(if you have registered a valid email address).
--
Razoo
That would be very kind. You can email via the wrightsaerials.tv website.

Bill

"Bill Wright" wrote in message
...

"mlv" wrote in message
...
Bill Wright wrote:

The cupboard has two doors, which open independently...
snip

Hi Bill,

I haven't got time to plough through this thread right now, but have you
resolved your light circuit problem?
No. The cabinet maker has agreed to make the panel at the top of the unit
removable, so I will be able to re-do the switches if neccessary, so I
thought I'd see whether the present disadvantages matter in practice.

It seems quite straightforward (your door switch contacts will have to be
wired in parallel).
If they are in parallel, to start the timing period the supply (or
trigger; it doesn't matter which) must be removed and then restored. So
both doors must be shut and then one or both opened. That's OK unless
you've left a door open and the timing period has ended when you want the
light on. It means that you have to shut the door then open it. Ideally I
wanted the light to come on if one door was opened, even if the other had
been left open previously.

A simple DE (Delay on Energisation) timer is all you seem to need. No
need for any relays.
Well, it's a multifuntion timer from RS, set to Delay on Energisation.

What supply and voltage are you using (e.g. mains 230V, 50Hz).
Mains.


I'll sketch you out a circuit over the next day or so and email it direct
(if you have registered a valid email address).
--
Razoo
That would be very kind. You can email via the wrightsaerials.tv website.

Bill


Did you see my post earlier - surely that would work, wouldn't it?

Toby...

Bill Wright wrote:

I wrote:

...have you resolved your light circuit problem?

No. The cabinet maker has agreed to make the panel at the top of the unit
removable, so I will be able to re-do the switches if necessary, so I
thought I'd see whether the present disadvantages matter in practice.

It seems quite straightforward (your door switch contacts will have to be
wired in parallel).

If they are in parallel, to start the timing period the supply (or
trigger; it doesn't matter which) must be removed and then restored. So
both doors must be shut and then one or both opened. That's OK unless
you've left a door open and the timing period has ended when you want the
light on. It means that you have to shut the door then open it. Ideally I
wanted the light to come on if one door was opened, even if the other had
been left open previously.

Yes, as Dave Plowman implied, I had missed the requirement for the light to
operate for the timed period when the second door is opened, despite the
first door had been left open and the light having.already timed out.

It's a tricky little circuit. I assume that the door monitoring switches
are single-pole normally closed, with the contact held open by the closed
door(s)?

Are the door monitoring switches available with a changeover contact?

Well, it's a multifunction timer from RS, set to Delay on Energisation.

Can you post the RS Stock number? There are so many timer functions listed,
it would be helpful to know what functions you have available.

I think that the most simple solution electrically (although possibly not
the best solution financially) would be to use two interval timers (RS timer
function 421 - On Pulse). These timers will work with the SPNC door
monitoring switches you already have to give you the circuit logic you want.
It's a very simple circuit using just 2 SPNC door switches, 2 interval
timers and the light.

Would you still like a circuit sketched out to show the two interval timers,
or is it obvious enough?

Suitable interval timers are RS Stock no. 160-262 (Tele Enya - Function Wu,
£23.39), RS Stock no. 300-5913 (Broyce, £22.00) or RS Stock no. 330-6654
(Broyce, £19.60). RS Stock no. 300-5913 is a dedicated interval timer (i.e.
not multifunction), and it is the one I would choose as it can't be
accidentally set to the wrong mode.
--
mlv

In article ,
Razoo wrote:
Yes, as Dave Plowman implied, I had missed the requirement for the light to
operate for the timed period when the second door is opened, despite the
first door had been left open and the light having.already timed out.

It's a tricky little circuit. I assume that the door monitoring
switches are single-pole normally closed, with the contact held open by
the closed door(s)?

Are the door monitoring switches available with a changeover contact?

I don't think they are, either push to make or push to break - hence my
idea of using alarm reed switches which are. But only if used to trigger
an electronic timer due to low power handling.

You could fit more than one switch I suppose, but there's a danger of the
rather strong springs making the door open.

--
*Save a tree, eat a beaver*

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Dave Plowman (News)
wrote:

You need to read Bill's requirements more carefully...


I have recently started playing with Microcontrollers (PICs).
This looks like an ideal application for one, just a bit of
easy software to knocjk up and it will do anything you ask.
The 16F630 I use is under £2.00. Outputs will drive a relay
directly and they can be battery powered if need be.

--
AJL Electronics (G6FGO) Ltd : Satellite and TV aerial systems
http://www.illifauthouse.co.uk : http://www.ajlelectronics.co.uk

In article ,
Andy Luckman (AJL Electronics) wrote:
In article , Dave Plowman (News)
wrote:

You need to read Bill's requirements more carefully...


I have recently started playing with Microcontrollers (PICs).
This looks like an ideal application for one, just a bit of
easy software to knocjk up and it will do anything you ask.
The 16F630 I use is under £2.00. Outputs will drive a relay
directly and they can be battery powered if need be.

Yes. I've got some literature and breadboards for these and I'm sure
they'd do lots of clever things. Just need the tuits. Might be the answer
to my 'fading' problem on another thread.

--
*Bigamy is having one wife too many - monogamy is the same

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Dave Plowman (News)
wrote:


Yes. I've got some literature and breadboards for these and I'm sure
they'd do lots of clever things. Just need the tuits. Might be the answer
to my 'fading' problem on another thread.


Well I am still a beginner and by no means an experienced, but I have so far
written four assembler programs into one controller, and it is all working
fine (ish). It is for a pair of electric gates. We had a commercial unit but
the software was terrible and wouldn't work logically for the customer's
requirements. So I designed my own!

Feel free to call me if you wish and I might be able to give you some
pointers.

To start off, I bought a PIC Kit 1 from Microchip. It comes with some PICs
to play with and a set of tutorials. It also programs and tests them.

There is free development software which has to be run BillyGoat side on
http://www.microchip.com inc debugging tools and a simulator. They give you
a C compiler too, whatever that might be :-)

There is Acorn software available, but I found it was so close to Microchip
assembler, it was better to use that and save £100!

--
AJL Electronics (G6FGO) Ltd : Satellite and TV aerial systems
http://www.illifauthouse.co.uk : http://www.ajlelectronics.co.uk