Simple sleep timer circuit - how?

M

Michael

Guest
Hi,

I would like to build a *very simple* "sleep timer" circuit to incorporate
into a stereo system. It should switch the mains, and could even be in a
separate small box. The idea is to press a button to give me power for one
hour only.

Anybody built/seen anything like this?

Thanks,
Michael
 
Hi Michael,

In the US these are sold in hardware stores. A knob is turned to
whatever time you want it on and it directly switches mains. Not much in
there except a mechanical timer and a switch. Possibly they also have
electronic ones. Mostly this is used to keep a fan on in the bathroom
after a, well, you know, or to keep a spa pump motor running for a
desired time.

Should be available in Australia as well.

Good Day, Joerg

http://www.analogconsultants.com
 
On Sun, 26 Sep 2004 08:40:42 +1000, Michael wrote:

Hi,

I would like to build a *very simple* "sleep timer" circuit to incorporate
into a stereo system. It should switch the mains, and could even be in a
separate small box. The idea is to press a button to give me power for one
hour only.

Anybody built/seen anything like this?

Thanks,
Michael
Click to expand...

Years ago I had a clock radio that the radio had failed..... I removed the
radio circuit board and fitted a relay switching the mains, also a 3 core
mains lead. The relay coil was 12 volt, to suit the
switched DC voltage output from the clock circuitry. Where the speaker
used to be, I fitted a small size power point outlet....

Set the alarm and it would turn the hifi on at that time....
set the snooze to play the hifi for an hour....
use the radio on function switch to turn the hifi on for an indefinite
period of time.


Pip
 
Thank you. :)

Unfortunately the power outlet is hidden, but maybe the guts of the thing
could be put in a box with a power cord.
Hmmm.....

regards,
:)
Michael



"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:NEm5d.1470$JG2.917@newssvr14.news.prodigy.com...
Hi Michael,

In the US these are sold in hardware stores. A knob is turned to whatever
time you want it on and it directly switches mains. Not much in there
except a mechanical timer and a switch. Possibly they also have electronic
ones. Mostly this is used to keep a fan on in the bathroom after a, well,
you know, or to keep a spa pump motor running for a desired time.

Should be available in Australia as well.

Good Day, Joerg

http://www.analogconsultants.com
Click to expand...
 
What a fantastic idea!

Thank you...
:)
Michael


"Ms_Squiggles" <send_pdreeves_no_spam@bigpond.net.au> wrote in message
news:pan.2004.09.25.22.22.05.578872@bigpond.net.au...
On Sun, 26 Sep 2004 08:40:42 +1000, Michael wrote:

Hi,

I would like to build a *very simple* "sleep timer" circuit to
incorporate
into a stereo system. It should switch the mains, and could even be in a
separate small box. The idea is to press a button to give me power for
one
hour only.

Anybody built/seen anything like this?

Thanks,
Michael


Years ago I had a clock radio that the radio had failed..... I removed the
radio circuit board and fitted a relay switching the mains, also a 3 core
mains lead. The relay coil was 12 volt, to suit the
switched DC voltage output from the clock circuitry. Where the speaker
used to be, I fitted a small size power point outlet....

Set the alarm and it would turn the hifi on at that time....
set the snooze to play the hifi for an hour....
use the radio on function switch to turn the hifi on for an indefinite
period of time.


Pip
Click to expand...
 
"Michael" <idealist@tpg.com.au> wrote in message
news:4155f3e8$1@dnews.tpgi.com.au...
Hi,

I would like to build a *very simple* "sleep timer" circuit to incorporate
into a stereo system. It should switch the mains, and could even be in a
separate small box. The idea is to press a button to give me power for
one hour only.

Anybody built/seen anything like this?

Thanks,
Michael
Click to expand...
I would think that a simple 555 timer circuit would do this - set up as a
one shot timer. Plenty of circuits on the internet, just Google for 555
timer, and all parts available from Dick Smith/Tandy/Jaycar, etc, etc....
The timer circuit can drive a relay - if you use a relay with suitably rated
contacts then you could switch the AC....

I built a 24v timer to turn the light in the back of a rescue truck off
after 10 minutes - press a button and the timer starts, 10 minutes later it
turns the relay off and the light goes off. Ran the circuit straight off
the 24VDC power using a 12 volt regulator to run the IC and relay... You
could do similar for 240VAC as the curcuit doesn't use much power so a very
simple regulated power supply could be built to run the thing, if absolute
precise timing isn't needed (i.e. 1 hour +/- 1 - 2 minutes..)

To save some trouble I actually used the Jaycar timer kit and modified the
circuit a little to suit my needs. Probably have the schematic here of the
changed circuit, but try the Google trick first because 555 timer circuits
aren't very difficult at all..

Cheers

Martin, VK2UMJ
 
Michael wrote:

Hi,

I would like to build a *very simple* "sleep timer" circuit to incorporate
into a stereo system. It should switch the mains, and could even be in a
separate small box. The idea is to press a button to give me power for
one hour only.

Anybody built/seen anything like this?

Thanks,
Michael
Click to expand...
Theres a HUGE home autopmation industry that does this sort of thing.
Its a big seller in the US at http://www.x10.com/

For 240V you can try http://www.eon3.com/

gtoomey
 
$29.95 at officeworks for a Belkin TimerCube ..

these have gone sellthru, which means end of line .. but most stores
probably still have stock at this point ..



"Michael" <idealist@tpg.com.au> wrote in message
news:4155f3e8$1@dnews.tpgi.com.au...
Hi,

I would like to build a *very simple* "sleep timer" circuit to incorporate
into a stereo system. It should switch the mains, and could even be in a
separate small box. The idea is to press a button to give me power for
one hour only.

Anybody built/seen anything like this?

Thanks,
Michael
Click to expand...
 
"Michael" <idealist@tpg.com.au> wrote in message
news:41561bea@dnews.tpgi.com.au...
Thank you. :)

Unfortunately the power outlet is hidden, but maybe the guts of the thing
could be put in a box with a power cord.
Hmmm.....

regards,
:)
Michael

Or maybe on the end of an extension cord? Look in the electrical section at
Click to expand...
Bunnings, maybe even at Kmart. Leave the guts behind the safety rated
enclosure where they belong.

Cheers,
Alf.
 
Hello Michael,

Unfortunately the power outlet is hidden, but maybe the guts of the thing
could be put in a box with a power cord.
Hmmm.....


Yes, but it may be the least work since you'd have to make a box anyway.
Click to expand...
You may also need another switch to bridge the timer for normal
operation, so it would be a double box. As long as you comply with
safety regs it should be ok.

If your stereo has a clock in there check it out. We had one in our
previous stereo and years later I found out that it also had a setting
with exactly the feature you described.

Regards, Joerg

http://www.analogconsultants.com
 
I am not sure if a 555 would work for a time delay of one hour.
The leakage current through the capacitor may be a problem.

A 4060 oscillator/binary counter should cover one hour very easily.

Russell.
 
I have been away for a week, and have come back to all these replies. :)

Thanks all for your suggestions. Ultimately I modified a clock radio by
replacing the dial lamp (9VDC) with a relay, switching 240V to a socket on
the back.

This works a treat, and gives me all the clock radio functions, but I am a
little uneasy about the safety rating, and will try some of your other ideas
as well. (instead).

Thanks again all of you,
:)
Michael
 
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