I am submitting this instructable to the Arduino challenge. Please remember to vote!
My neighbor had a little problem with his cat. It want’s to go out and back inside too frequently. Usually he opens just his kitchen window and let’s the cat in/out. Usually the cat stays only short periods outside and want’s soon to come back inside. And then again out and back in. Okay, he could just let the window open, but here in Finland it can be easily -30 C (-22 F) in winter, so this is not a good solution.
We decided to build a microcontroller to the window to open and close the window automatically. Arduino controls a strong servo motor, which moves the window. It has three proximity sensors to sense where the is cat is.
Step 1: Parts list
small window hinge
some metal parts to fix the servo to the window frame, screws, etc
Solder & soldering iron
Computer & usb cable to program the Arduino
Step 2: Mechanics
We made adjustable arm from copper rod. Don’t fix the servo arm with screw until you have first driven the servo to zero (closed) position with the control program. The good thing in this is that the mechanics are easily adjustable.We chose Towerpro servo with metal gears to get long life for the installation. It does move the window easily enough but it can not slice the cat (nor anything else). The closing speed is set to very slow.
There are dfx files of the servo bracket and actuator arm included.
Step 3: Sensor placement
We placed three sensors, two between the windows (works well through the glass) and one at the opening window, so the window doesn’t close if the cat just looks outside. The good thing that in these Pololu boards are tiny SMD-leds. You see directly when the sensor is detecting an object.
For more detail: Arduino controlled window for cat