Abstract: A system may include a wearable electronic device that gathers force input. The device may transmit force measurement information and other input to external equipment such as a head-mounted device. The wearable electronic device may have a force sensor that gathers force measurements as the wearable electronic device is being worn. The force sensor may have a force sensor housing structure configured to form a fluid-filled channel and one or more collapsible force sensor elements such as collapsible fluid-filled domes or other protruding portions of the force sensor housing structure. A pressure sensor may monitor changes in pressure in a fluid that fills the channel and the fluid-filled domes. The monitored changes in pressure represent force measurements for force applied by a user's body part or other objects on the collapsible force sensor elements.

Abstract: A wireless power transmitting device transmits wireless power signals to a wireless power receiving device. To detect foreign objects, the wireless power transmitting device has an array of temperature sensors. The array of temperature sensors may include temperature sensor components such as temperature sensitive thin-film resistors or other temperature sensitive components. A temperature sensor may have thin-film resistors formed on opposing sides of a substrate. The thin-film resistors may be formed from meandered metal traces to reduce eddy current formation during operation of the wireless power transmitting device. Signal paths coupling control circuitry on the wireless power transmitting device to the array of temperature sensors may be configured to extend along columns of the temperature sensors without running along each row of the temperature sensors, thereby reducing eddy currents from loops of signal routing lines.

Abstract: A wireless power transmitting device transmits wireless power signals to a wireless power receiving device. To detect foreign objects, the wireless power transmitting device has an array of temperature sensors. The array of temperature sensors may include temperature sensor components such as temperature sensitive thin-film resistors or other temperature sensitive components. A temperature sensor may have thin-film resistors formed on opposing sides of a substrate. The thin-film resistors may be formed from meandered metal traces to reduce eddy current formation during operation of the wireless power transmitting device. Signal paths coupling control circuitry on the wireless power transmitting device to the array of temperature sensors may be configured to extend along columns of the temperature sensors without running along each row of the temperature sensors, thereby reducing eddy currents from loops of signal routing lines.

Abstract: A wireless power transmitting device transmits wireless power signals to a wireless power receiving device. The wireless power receiving device has a rectifier and a wireless power receiving coil that receives wireless power signals. The wireless power transmitting device uses a layer of coils to transmit the wireless power signals. A dielectric layer in the wireless power transmitting device defines a charging surface that receives the wireless power receiving device. A layer of temperature sensors is interposed between the layer of coils and the dielectric layer. Control circuitry in the wireless power transmitting device uses temperature information from the temperature sensors to determine whether a foreign object such as a coin is present on the charging surface.

Abstract: A wireless power transmitting device transmits wireless power signals to a wireless power receiving device. The wireless power receiving device has a rectifier and a wireless power receiving coil that receives wireless power signals. The wireless power transmitting device uses a layer of coils to transmit the wireless power signals. A dielectric layer in the wireless power transmitting device defines a charging surface that receives the wireless power receiving device. A layer of temperature sensors is interposed between the layer of coils and the dielectric layer. Control circuitry in the wireless power transmitting device uses temperature information from the temperature sensors to determine whether a foreign object such as a coin is present on the charging surface.

Abstract: A wireless power transmitting device transmits wireless power signals to a wireless power receiving device. To detect foreign objects, the wireless power transmitting device has an array of temperature sensors. The array of temperature sensors may include temperature sensor components such as temperature sensitive thin-film resistors or other temperature sensitive components. A temperature sensor may have thin-film resistors formed on opposing sides of a substrate. The thin-film resistors may be formed from meandered metal traces to reduce eddy current formation during operation of the wireless power transmitting device. Signal paths coupling control circuitry on the wireless power transmitting device to the array of temperature sensors may be configured to extend along columns of the temperature sensors without running along each row of the temperature sensors, thereby reducing eddy currents from loops of signal routing lines.