Electronic devices with sensors

A head-mounted device, comprising:

• a housing;
• first and second optical assemblies that are supported by the housing and that are configured to display images to first and second respective eye boxes;
• first and second actuators configured to respectively move the first and second optical assemblies with respect to each other to accommodate an interpupillary distance;
• a capacitive sensor configured to make capacitance measurements, wherein the first and second actuators are configured to halt movement of the first and second optical assemblies towards each other based at least partly on the capacitance measurements;
• and
• a fabric curtain coupled to the housing, wherein the capacitive sensor has a first electrode on the fabric curtain and a second electrode on the first optical assembly.

A head-mounted device, comprising:

• a head-mounted housing;
• first and second optical assemblies that are supported by the head-mounted housing and that are configured to display images in first and second respective eye boxes;
• at least one actuator configured to move the first and second optical assemblies with respect to each other to accommodate an interpupillary distance;
• a sensor having at least first and second electrodes located respectively on the first and second optical assemblies, wherein the actuator is configured to halt movement of the first and second optical assemblies towards each other at least partly based on information from the sensor;
• and
• a cover coupled to the head-mounted housing, wherein the sensor further comprises third and fourth electrodes on the cover.