I live in an apartment that has sliding windows in it. The apartment is naturally warm because we live above a mechanical room, such that we either opened the windows or ran the air conditioning through the winter. I want to create a device than can open and close the windows in the apartment depending on temperature. The software and electronics are already figured out, I just need to figure out how to move the windows.
This is a sample of the window. It takes about 4 lbs of force to pull it open, and they only open 6 inches(since I'm 16 stories high).
Ultimately, I want to make this cheap enough that I could replicate it on 6 windows.
My first thought was a linear actuator, but most of the ones I have seen are designed for moving 100+lbs and cost several hundred dollars. Pneumatic actuators are cheaper, but I'd have to run a network of air lines and solenoids, and would have a compressor that would randomly kick in. A double winch system would be very complicated to set up and prone to failure. Lastly, I was thinking of a cheap metal gear servo(dealextreme has 15kg/cm servos for under $15.00), but it would be somewhat difficult to use a series of turnbuckles and arms to translate into 6 inches of linear movement.
Any help would be appreciated.