Abstract: Electronic devices may be provided with compasses for detecting the Earth's magnetic field. Electronic devices may be provided with other electronic components. A compass may include a magnetic sensor and control circuitry configured to apply offsets or other compass calibration data to compass data to compensate for magnetic interference from the other electronic components. Other electronic components may include components such as cameras, auto-focus lens mechanisms, light sources, and displays. The control circuitry may be configured to apply compass calibration data that is specific to an electronic component and that is specific to an operational status of the component. The control circuitry may be configured to recognize a replacement electronic component and revert to an average compass calibration correction. The control circuitry may be configured to output interference-corrected compass data to applications running on the electronic device.

Abstract: Electronic devices may be provided with compasses for detecting the Earth's magnetic field. Electronic devices may be provided with electronic components that generate interfering magnetic fields for the compass. Electronic components may be coupled between a power supply line and a power return line on a printed circuit. The power return line may be configured to generate a compensating magnetic field to counteract the interfering magnetic fields. The power return line may be formed parallel to the power supply line. The power supply line may have multiple branches equidistant from the compass. The power return line may have a portion closer to the compass than the power supply line and the electronic component. The power return line may have multiple branches, may be provided with resistors on each branch and may include a portion of a circular loop the runs around the compass on the printed circuit board.

Abstract: We provide a system and method for temporarily coupling a beverage purchase with an RFID tag or other media, then recovering the RFID tag or other media for reuse after the beverage has been dispensed. Media may be, for example, but are not limited to cards (including plastic, cardboard, or paper cards), keychains, or key fobs.

Abstract: Electronic devices may be provided with compasses for detecting the Earth's magnetic field. Electronic devices may be provided with electronic components that generate interfering magnetic fields for the compass. Electronic components may be coupled between a power supply line and a power return line on a printed circuit. The power return line may be configured to generate a compensating magnetic field to counteract the interfering magnetic fields. The power return line may be formed parallel to the power supply line. The power supply line may have multiple branches equidistant from the compass. The power return line may have a portion closer to the compass than the power supply line and the electronic component. The power return line may have multiple branches, may be provided with resistors on each branch and may include a portion of a circular loop the runs around the compass on the printed circuit board.

Abstract: Electronic devices may be provided with compasses for detecting the Earth's magnetic field. Electronic devices may be provided with other electronic components. A compass may include a magnetic sensor and control circuitry configured to apply offsets or other compass calibration data to compass data to compensate for magnetic interference from the other electronic components. Other electronic components may include components such as cameras, auto-focus lens mechanisms, light sources, and displays. The control circuitry may be configured to apply compass calibration data that is specific to an electronic component and that is specific to an operational status of the component. The control circuitry may be configured to recognize a replacement electronic component and revert to an average compass calibration correction. The control circuitry may be configured to output interference-corrected compass data to applications running on the electronic device.