<p>My window spans two floors which was a big advantage in this case. The window cannot open far enough for any intruder to go in and i could install the steppermoter on the second floor where it is out of the way.</p><p>I installed the stepper motor upstairs and attached it with only one screw so it can rotate a bit. This is neccesary because the window frame doesn't move along a line but along a curve. It also enables you to move the threaded rod out off the nutholder so you can manually open and close the window.</p><p>To attach the threaded rod to the axis of the stepper you'll need couplings. My Stepper motor has a pulley fixed on it so i had to use the couplings that i also uploaded. For a normal stepper motor you can find lots of couplings by searching for Z coupling on Thingiverse.</p><p>I used a lasercutter to cut the nutholderpieces from 5mm birch plywood. I drilled a little hole in the top so i could use a pin to keep the threaded rod inside the nutholder. If i want to manually open the window i can take the pin out and move the threaded rod out of the nutholder.</p><p>Now you have a motor that can open and close a window. Next thing is the electronics to control the motor. I used an Arduino uno with a shield that allowed me to connect a steppermotor, 2 sensors ,a 12v powersupply, some leds and a stepper motor driver. I made the shield from a piece of prototyping board<br></p><p>You can find the schematics and the code for the uno in the documents.</p><p>To connect the pir motion sensors to the shield i used an old network cable, it has 8 threads of which i only needed 6.</p>
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