Author Options:

How to make my house window open (and then later close) horizontally (linearly) on a timer? Answered

I have a fan on a timer in my house but I need a window to open and close so that the fan is effective (it will be opening during the day in the winter and during the night in summer.)

The window is 3 feet by 4 feet. I was thinking of using a jackscrew set-up, but all the diagrams I've seen have an SPDT switch, which won't help me because I'll be asleep or at work.

So I need both the ability to connect it to some kind of timer AND the ability to open AND close separately.

The idea of re-purposing a garage door opener strikes me as a good idea, but it's massive overkill. But it would have most of the attributes I need--I would just have to have a timer trip the circuit and HOPE it never gets out of sync and mistakes open for close.


Use an spdt relay. You can hook it up to your timer or what ever controls your fan and it will open and close the window in time with your fan. You'll have to set up limit switches and a power supply for the linear motor.

But I don't think that helps me.

The fan is either on or off. Electricity is on or off.
But the window will have to move one directions at the application (and then it can stop with the limit switch) but then it has to go the other direction when the power is switched off.
I don't think an SPDT relay alone will do this. Am I wrong?

When the fan is on the relay is on and the contacts cause the window motor to open the window. The limit switch stops it.

When the fan turns off the relay turns off and the relay contacts cause the window motor to close the window.

Fantastic! I was wrong :)
So I believe it will need some diodes, too.
Do you have any idea of what to spec for the motor and diodes and relays?
Making the limit switch is the easy part!

No diodes needed that I can see. choose the motor and mechanism then you know what size your relay, power supply etc. are needed.

I love the idea of the drill--I think that's the way I'm going to do it. 12V DC (and I'll just recharge it every once in a while).
So I'm going to need to have the AC power ON have a relay actuate the drill to on, then the window will open to the limit switch.
Then when the AC powers off I need to have a relay to reverse the direction and close until another limit switch.
What type of relays should I be looking for? I know most electronics but I'm absolutely clueless when it comes to relays!

Linear actuator made from a cordless drill motor. Only needs 3 volts to operate and with a little ingenuity you can bridge the original switch with relay contacts to make it go bach and forward.

The original switch forms a mechanical H bridge.


shows lots

Use an extractor fan instead, they have self-actuating louvres these days.


Ummm, that's actually not the issue. I have a roof fan in the ceiling of one room and only one openable window that's in the next room. So the window in the next room needs to open for there to be any flow.

The roof fan was easy--there are electric switches that mount into a typical electrical box that have a timer.

But the issue is I will need to have the window move one direction with the application of power, and then move the OTHER way the next time there is a signal.

The hard bit is the motor. You could use a screw drive, but how about an electric curtain opener ?

You're the first person to ever come up with the idea of the curtain opener! However, these are all WAY expensive (>$300) so it's too expensive for me.