A sleep mode system for an electronic device can include a magnetic component and a proximately located sensor configured to detect magnetic field properties that vary with a variable rotation of the magnetic component. The magnetic component can rotate with one device component, such as a laptop lid, while the sensor remains stationary with another device component, such as a laptop base. A controller can determine the orientation angle of the magnetic component based on the detected properties, and can put the device into or remove the device from a sleep mode based on the angle, which can reflect an open state or closed state for the electronic device.