Sometimes it’s nice to have the ability to open windows remotely, especially on a hot day, to let hot air out.
With my window switch modification for the automatic roll up feature, the only issue was operation when the car’s power is off. Finally, I was able to figure out how to wake up the window switch remotely, which provided an opportunity to add control from the remote key fob.
With the help of the external microcontroller, I can now detect the lock/unlock functions and control the windows. In my current implementation, when you double-click on the lock button, the windows will go up, and when you double-click on the unlock button the windows will go down. communication with the window switch is done over LIN wire, which goes between the two doors. The information about lock/unlock status I’m getting from CAN bus. The microcontroller normally is in sleep mode, to avoid unnecessary battery drain. It will wake up on any CAN bus activity, which starts when any button on the remote is pressed.
I made a quick prototyping of this controller and designed a small PCB (1.6″ x 0.9″). The controller will be tapped in to 5 wires: CAN-L/CAN-H, LIN, +12V and Ground. All 5 wires are easily accessible near the passenger door connector.