A device, comprising: a pair of force sensors located for detecting a user squeeze input; and a controller operable in a squeeze detection operation to detect the user squeeze input based on a cross-correlation between respective sensor signals originating from the pair of force sensors.

An apparatus may include an input surface, a plurality of key positions on the input surface, a force sensor positioned underneath the input surface at at least one of the key positions, and a proximity controller in communication with a capacitance measuring circuit incorporated into the apparatus.

In a driver for a piezo-electric transducer, when a converter circuit and a sensing circuit are the same circuit, many limitations exist on the accuracy of the sensing, due to multiple parasitic effects arising from the interconnection of the power devices. These limitations may limit viability of the sensing for many applications, in particular an accurate determination of when the force on the piezo-electric transducer is fully removed. Providing an additional switch in the sensing circuit configured to repeatedly zero the sensed voltage across the piezo-electric transducer each time the sensed voltage reaches a threshold voltage generates a plurality of voltage segments between zero and the threshold voltage. Accordingly, a controller may then be configured to generate a digital reconstruction of the sensed voltage across the piezo-electric transducer by adding the plurality of voltage segments.

A physical disturbance sensor includes a plurality of piezoresistive elements configured in a resistive bridge configuration. A signal transmitter is electrically connected to the physical disturbance sensor and configured to send an encoded signal to the piezoresistive elements of the resistive bridge configuration. A signal receiver is electrically connected to the piezoresistive elements and configured to receive a signal from the physical disturbance sensor. The received signal from the physical disturbance sensor is correlated with the sent encoded signal in determining a measure of physical disturbance.

An electronic device has a keyboard with an internal membrane. The membrane has a set of strain gauges configured to respond to a key press, such as when a collapsible dome collapses into contact with the membrane. The strain gauges are connected in a half Wheatstone bridge configuration and are positioned on the membrane in order to limit effects of temperature and subtle flexure of the membrane. The strain gauges are also configured to magnify detection of a resistance differential when a keycap is pressed with sufficient force.

A device, comprising: a pair of force sensors located for detecting a user squeeze input; and a controller operable in a squeeze detection operation to detect the user squeeze input based on a cross-correlation between respective sensor signals originating from the pair of force sensors.

Embodiments may take the form of a system having a user input device and a first sensor coupled to the user input device. The first sensor is configured to sense touch on a surface of the user input device. The system may also include a second sensor in communication with the surface of the user device configured to sense wetting of a user's fingerprint on the surface. The system has a processor coupled to the first and second sensors and configured to estimate an amount of force applied by the user's fingerprint based at least in part upon the sensed wetting of the user's fingerprint.

A haptic keyboard of an information handling system may include a coversheet to identify a key location of the haptic keyboard; a support layer; a contact foil placed between the coversheet and support layer; a piezoelectric element placed between the contact foil and support layer to receive an applied mechanical stress at the key location of the coversheet and generate an electric actuation signal; and a controller of the information handling system operatively coupled to the contact foil to: receive an electric actuation signal from the piezoelectric element placed under the mechanical stress via the contact foil; and send an electrical response signal to the piezoelectric element to cause the piezoelectric element to generate haptic feedback at the key location.

A sense circuit for a piezoresistive sensor is provided that comprises: an energy storage circuit coupled to the piezoresistive sensor via a first node; a charge control circuit coupled to the first node and configured to charge the energy storage circuit to a predetermined potential; a discharge control circuit configured to allow the energy storage circuit to discharge through the piezoresistive sensor; and a readout circuit coupled to the first node and configured to output a sensed voltage based on a level of charges stored by the energy storage circuit.

A portable computer includes a display portion comprising a display, a base portion pivotally coupled to the display portion and including a glass top case. The glass top case defines an exterior surface and a keyboard opening through the glass top case from the exterior surface to an interior surface. The portable computer further includes a keyboard positioned at least partially within the keyboard opening and comprising a substrate, a key configured to move relative to the substrate, and a fabric cover disposed over the key and defining a user interface surface of the key.