Light Switch Then Fan On Timer

dracul · 6th January 2006, 02:55 AM

How can i have a switch that turns off the lamp and everything else but keeps the fan running for another 60 seconds?

rob1231 · 6th January 2006, 04:55 PM

get one of those heat lamp timers for bathrooms maybe. Then you could set it so that the fan would stay on for another minute or something. Tell us what you come up with.

Luca Brazzi · 11th January 2006, 04:38 AM

Difficult problem...

Whatever you use needs to automatically reset to a 1 minute timeout everytime you turn on your projector so a mechanical timer wouldnt work... it would have to be an electronic timer that you could program for 1 minute. It would also need to control the power to your fans. The thing is... if you are turning on your projector via a mechanical switch that is inline with the AC into your projector, once you turn that off... where does the stored power come from to keep the fans running?

My solution was to build a projector controller, but that may be more than what you are looking for.

shardian · 11th January 2006, 03:12 PM

I have a 2 position switch to control power. Everything is wired to one side for PJ operation. The fan wires will be split and ran to poth operational sides of the switch. This way, after I'm done with the pj, I can flip the switch over and only leave the fans on. One thing I have thought of is incorporating one of the bathroom motion sensor switches. The manual timer ones will wind down regardless, but the motion sensor version will only work when power is applied to it. So, if i wire it in line with the fan side of the switch. Voila! Instant fan timer for however long I want. The beauty is there is no motion inside the box of course, so there is no chance of the fans turning back on, and even if they did, it would only be for a minute or three.
You don't have to use a 2 position switch, but I just don't want a ton of switches on the side of my box. Please let me know what you think.

doublejack · 11th January 2006, 03:44 PM

I've thought about this too and this is the solution I came up with. You take a relay and wire it to provide power when it's grounded. That relay powers your electronic timer (the aforementioned bathroom motion sensor is a great timer option). The timer is connected to an ATX style computer power supply, which gets switched on by the timer and runs the fans.

One could really use this system with any power source, but a 2nd relay would be required.

dnsey · 11th January 2006, 05:24 PM

If you can find the timeswitch used on tumble dryers, which allows about 10 mins cold tumbling at the end of the cycle, it could no doubt be modified to do this job - just needs to be locked on when 'heat' (i.e. lamp etc) is selected.

shardian · 12th January 2006, 12:13 PM

I would venture to say it is much easier to go to lowes and pay $15 for the motion timer than track down a dryer that has that function, buy it and strip it down and hope it works. Just my 2 cents.

dnsey · 12th January 2006, 11:50 PM

Some of us have bits like that stashed away already

Never dump any appliance until everything useful has been removed

Luca Brazzi · 13th January 2006, 03:47 PM

If youre interested in seeing my solution... heres the thread

If I only had a Brain!

I used a 3 minute cool down period though...

Miedosoracing · 13th January 2006, 08:56 PM

I posted this elsewhere, but I will give you the best info. The best way to do what you want. Use a thermostat. It turns the fan on at say 100 degrees and turns them off at 100 degrees. When the pj is turned on you will be well over 100 degrees. So it will be on. But after that, when it is cool it will switch back off. Good luck

6th January 2006, 02:55 AM	#1
dracul diyAudio Member Join Date: Jul 2003 Location: Brazil	Light Switch Then Fan On Timer How can i have a switch that turns off the lamp and everything else but keeps the fan running for another 60 seconds? __________________ 1900x1200 All the way baby!!!

6th January 2006, 04:55 PM	#2
rob1231 diyAudio Member Join Date: Apr 2005 Location: Ontario	get one of those heat lamp timers for bathrooms maybe. Then you could set it so that the fan would stay on for another minute or something. Tell us what you come up with. __________________ Rob Smith

11th January 2006, 04:38 AM	#3
Luca Brazzi diyAudio Member Join Date: Dec 2002 Location: VA	Difficult problem... Whatever you use needs to automatically reset to a 1 minute timeout everytime you turn on your projector so a mechanical timer wouldnt work... it would have to be an electronic timer that you could program for 1 minute. It would also need to control the power to your fans. The thing is... if you are turning on your projector via a mechanical switch that is inline with the AC into your projector, once you turn that off... where does the stored power come from to keep the fans running? My solution was to build a projector controller, but that may be more than what you are looking for. __________________ No matter where you go there you are.

13th January 2006, 03:47 PM	#9
Luca Brazzi diyAudio Member Join Date: Dec 2002 Location: VA	If youre interested in seeing my solution... heres the thread If I only had a Brain! I used a 3 minute cool down period though... __________________ No matter where you go there you are.

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11th January 2006, 03:12 PM	#4
shardian diyAudio Member Join Date: Oct 2005	I have a 2 position switch to control power. Everything is wired to one side for PJ operation. The fan wires will be split and ran to poth operational sides of the switch. This way, after I'm done with the pj, I can flip the switch over and only leave the fans on. One thing I have thought of is incorporating one of the bathroom motion sensor switches. The manual timer ones will wind down regardless, but the motion sensor version will only work when power is applied to it. So, if i wire it in line with the fan side of the switch. Voila! Instant fan timer for however long I want. The beauty is there is no motion inside the box of course, so there is no chance of the fans turning back on, and even if they did, it would only be for a minute or three. You don't have to use a 2 position switch, but I just don't want a ton of switches on the side of my box. Please let me know what you think.

11th January 2006, 03:44 PM	#5
doublejack diyAudio Member Join Date: Dec 2005 Location: Motor City	I've thought about this too and this is the solution I came up with. You take a relay and wire it to provide power when it's grounded. That relay powers your electronic timer (the aforementioned bathroom motion sensor is a great timer option). The timer is connected to an ATX style computer power supply, which gets switched on by the timer and runs the fans. One could really use this system with any power source, but a 2nd relay would be required.

11th January 2006, 05:24 PM	#6
dnsey diyAudio Member Join Date: Mar 2004 Location: Shropshire, England	If you can find the timeswitch used on tumble dryers, which allows about 10 mins cold tumbling at the end of the cycle, it could no doubt be modified to do this job - just needs to be locked on when 'heat' (i.e. lamp etc) is selected.

12th January 2006, 12:13 PM	#7
shardian diyAudio Member Join Date: Oct 2005	I would venture to say it is much easier to go to lowes and pay $15 for the motion timer than track down a dryer that has that function, buy it and strip it down and hope it works. Just my 2 cents.

12th January 2006, 11:50 PM	#8
dnsey diyAudio Member Join Date: Mar 2004 Location: Shropshire, England	Some of us have bits like that stashed away already Never dump any appliance until everything useful has been removed

13th January 2006, 08:56 PM	#10
Miedosoracing diyAudio Member Join Date: Oct 2005	I posted this elsewhere, but I will give you the best info. The best way to do what you want. Use a thermostat. It turns the fan on at say 100 degrees and turns them off at 100 degrees. When the pj is turned on you will be well over 100 degrees. So it will be on. But after that, when it is cool it will switch back off. Good luck

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